calibration bath user’s guide

6055Calibration Bath

User’s Guide

Rev. 5A1102

Hart Scientific

Limited Warranty & Limitation of Liability

Each product from Fluke Corporation, Hart Scientific Division (“Hart”) is war-ranted to be free from defects in material and workmanship under normal use andservice. The warranty period is one year for the Calibration Bath. The warranty pe-riod begins on the date of the shipment. Parts, product repairs, and services are war-ranted for 90 days. The warranty extends only to the original buyer or end-usercustomer of a Hart authorized reseller, and does not apply to fuses, disposable bat-teries or to any other product which, in Hart’s opinion, has been misused, altered,neglected, or damaged by accident or abnormal conditions of operation or handling.Hart warrants that software will operate substantially in accordance with its func-tional specifications for 90 days and that it has been properly recorded on non-de-fective media. Hart does not warrant that software will be error free or operatewithout interruption. Hart does not warrant calibrations on the Calibration Bath.

Hart authorized resellers shall extend this warranty on new and unused products toend-user customers only but have no authority to extend a greater or different war-ranty on behalf of Hart. Warranty support is available if product is purchasedthrough a Hart authorized sales outlet or Buyer has paid the applicable internationalprice. Hart reserves the right to invoice Buyer for importation costs of repairs/re-placement parts when product purchased in one country is submitted for repair inanother country.

Hart’s warranty obligation is limited, at Hart’s option, to refund of the purchaseprice, free of charge repair, or replacement of a defective product which is returnedto a Hart authorized service center within the warranty period.

To obtain warranty service, contact your nearest Hart authorized service center orsend the product, with a description of the difficulty, postage, and insurance prepaid(FOB Destination), to the nearest Hart authorized service center. Hart assumes norisk for damage in transit. Following warranty repair, the product will be returned toBuyer, transportation prepaid (FOB Destination). If Hart determines that the failurewas caused by misuse, alteration, accident or abnormal condition or operation orhandling, Hart will provide an estimate or repair costs and obtain authorization be-fore commencing the work. Following repair, the product will be returned to theBuyer transportation prepaid and the Buyer will be billed for the repair and returntransportation charges (FOB Shipping Point).

THIS WARRANTY IS BUYER’S SOLE AND EXCULSIVE REMEDY AND ISIN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUD-ING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OFMERCHANTABLILTY OR FITNESS FOR A PARTICULAR PURPOSE. HARTSHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL. ORCONSEQUENTIAL DAMAGES OR LOSSES, INCLUDING LOSS OF DATA,WHETHER ARISING FROM BREACH OF WARRANTY OR BASED ON CON-TRACT, TORT, RELIANCE OR ANY OTHER THEORY.

Since some countries or states do not allow limitation of the term of an implied war-ranty, or exclusion or limitation of incidental or consequential damages, the limita-tions and exclusions of this warranty may not apply to every buyer. If any provision

of this Warranty is held invalid or unenforceable by a court of competent juris-diction, such holding will not affect the validity or enforceability of any otherprovision.

Fluke CorporationHart Scientific Division799 E. Utah Valley Drive American Fork, UT 84003-9775 USAPhone: +1.801.763.1600Telefax: +1.801.763.1010Email: [email protected]

www.hartscientific.comSubject to change without notice. Copyright © 2005 Printed in USA

Table of Contents

1 Before you start . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 Symbols used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Safety information . . . . . . . . . . . . . . . . . . . . . . . . . . 21.2.1 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.2.2 Cautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.3 Authorized Service Centers. . . . . . . . . . . . . . . . . . . . . . 6

2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3 Specifications and environmental conditions . . . . . . . . . . 113.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.2 Environmental conditions . . . . . . . . . . . . . . . . . . . . . . 11

4 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134.1 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.2 Comments concerning the use of salt . . . . . . . . . . . . . . . . 14

4.3 Bath environment . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.4 “Dry-out” period . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.5 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.6 Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.7 Setting the temperature . . . . . . . . . . . . . . . . . . . . . . . 15

5 Bath Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

5.2 Comparison calibration . . . . . . . . . . . . . . . . . . . . . . . 17

5.3 Calibration of multiple probes. . . . . . . . . . . . . . . . . . . . 18

6 Parts and controls . . . . . . . . . . . . . . . . . . . . . . . . 196.1 Controller panel . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6.2 Power panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

6.3 Back panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

7 General operation . . . . . . . . . . . . . . . . . . . . . . . . 237.1 Two modes of temperature control . . . . . . . . . . . . . . . . . 23

7.1.1 Temperature control mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 237.1.2 Temperature drift mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

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7.2 Bath fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

7.3 Fluid system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

7.4 Fluid Drain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

7.5 Filling the bath . . . . . . . . . . . . . . . . . . . . . . . . . . . 257.5.1 Using heat transfer salt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

7.5.1.1 The first salt load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257.5.1.2 Melting the salt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

7.6 Stirring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

7.7 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

8 Controller operation . . . . . . . . . . . . . . . . . . . . . . . 298.1 Bath temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 29

8.2 Reset cut-out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

8.3 Temperature set-point . . . . . . . . . . . . . . . . . . . . . . . . 318.3.1 Programmable set-points . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318.3.2 Set-point value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328.3.3 Set-point vernier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

8.4 Temperature scale units . . . . . . . . . . . . . . . . . . . . . . . 33

8.5 Secondary menu . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

8.6 Heater power . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

8.7 Proportional band . . . . . . . . . . . . . . . . . . . . . . . . . . 34

8.8 Cut-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

8.9 Controller configuration. . . . . . . . . . . . . . . . . . . . . . . 37

8.10 Probe parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 378.10.1 R0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388.10.2 ALPHA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

8.11 Operating parameters . . . . . . . . . . . . . . . . . . . . . . . . 388.11.1 Cut-out reset mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388.11.2 Stir mode select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388.11.3 Stir set-point. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398.11.4 Heat up power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

8.12 Serial interface parameters . . . . . . . . . . . . . . . . . . . . . 408.12.1 Baud rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408.12.2 Sample period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418.12.3 Duplex mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418.12.4 Linefeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

8.13 IEEE-488 parameters . . . . . . . . . . . . . . . . . . . . . . . . 428.13.1 IEEE-488 address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

8.14 Calibration parameters . . . . . . . . . . . . . . . . . . . . . . . 428.14.1 CTO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438.14.2 CO and CG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438.14.3 H and L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

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9 Digital communication interface . . . . . . . . . . . . . . . . 459.1 Serial communications . . . . . . . . . . . . . . . . . . . . . . . 45

9.1.1 Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459.1.2 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

9.1.2.1 Baud rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469.1.2.2 Sample period. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469.1.2.3 Duplex mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469.1.2.4 Linefeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

9.1.3 Serial operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

9.2 IEEE-488 communication (optional) . . . . . . . . . . . . . . . . 479.2.1 Setup and address selection . . . . . . . . . . . . . . . . . . . . . . . . . . . 479.2.2 IEEE-488 operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

9.3 Interface commands . . . . . . . . . . . . . . . . . . . . . . . . . 47

9.4 Power commands . . . . . . . . . . . . . . . . . . . . . . . . . . 51

9.5 Heater settings for control . . . . . . . . . . . . . . . . . . . . . . 52

10 Calibration procedure . . . . . . . . . . . . . . . . . . . . . . 5310.1 Calibration points . . . . . . . . . . . . . . . . . . . . . . . . . . 53

10.2 Measuring the set-point error . . . . . . . . . . . . . . . . . . . . 53

10.3 Computing R0 and ALPHA . . . . . . . . . . . . . . . . . . . . . 53

10.4 Calibration example . . . . . . . . . . . . . . . . . . . . . . . . . 54

11 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

12 Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . 5912.1 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . 59

12.2 Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6112.2.1 EMC Directive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6112.2.2 Low Voltage Directive (Safety) . . . . . . . . . . . . . . . . . . . . . . . . . 61

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iv

Figures and Tables

Figure 1 Controller panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Figure 2 Power panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Figure 3 Back panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Figure 4 System diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Figure 5 System diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Figure 6 Controller operation flowchart . . . . . . . . . . . . . . . . . . . . . . 30Figure 7 Bath temperature fluctuations at various proportional band settings . . 35Figure 8 Serial Cable Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . 45Table 1 Interface command summary . . . . . . . . . . . . . . . . . . . . . . 48Table 1 Interface command summary cont. . . . . . . . . . . . . . . . . . . . 49Table 1 Interface command summary cont. . . . . . . . . . . . . . . . . . . . 50Table 2 Power Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52Figure 9 Calibration example . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

1 Before you start

1.1 Symbols usedTable 1 lists the International Electrical Symbols. Some or all of these symbolsmay be used on the instrument or in this manual.

Symbol Description

AC (Alternating Current)

AC-DC

Battery

CE Complies with European Union Directives

DC

Double Insulated

Electric Shock

Fuse

PE Ground

Hot Surface (Burn Hazard)

Read the User’s Manual (Important Information)

Off

On

1

1 Before you startSymbols used

Table 1 International Electrical Symbols

Symbol Description

Canadian Standards Association

OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per IEC1010-1 re-fers to the level of Impulse Withstand Voltage protection provided. Equipment ofOVERVOLTAGE CATEGORY II is energy-consuming equipment to be supplied fromthe fixed installation. Examples include household, office, and laboratory appliances.

C-TIC Australian EMC Mark

1.2 Safety information

DISCLAIMER: Fluke Corporation, Hart Scientific Division manufac-tures baths for the purpose of temperature calibration. Baths used for ap-plications other than calibration are used at the discretion and soleresponsibility of the customer. Hart Scientific cannot accept any responsi-bility for the use of baths for any application other than temperature cali-bration.

Use this instrument only as specified in this manual. Otherwise, the protectionprovided by the instrument may be impaired.

The following definitions apply to the terms “Warning” and “Caution”.

• “Warning” identifies conditions and actions that may pose hazards to theuser.

• “Caution” identifies conditions and actions that may damage the instru-ment being used.

1.2.1 WarningsTo avoid personal injury, follow these guidelines.

GENERAL

• Appropriate personal safety protection should be worn by the operator atall times while using the bath.

• Hart Scientific does not recommend that user’s drain the salt from thebath. Hart Scientific provides the service of draining salt from the bath. Ifdraining the bath salt is necessary, contact an Authorized Service Center(see Section 1.3) for an RMA and instructions on returning the bath. In-sure that the control probe is removed from the bath before the salt solidi-fies. Solidification in the bath can take up to several days. If the controlprobe is not removed before shipping the bath, the control probe may bedamaged during shipping and the Service Centers assume no liability fordamage incurred during shipping.

6055 Calibration Bath

User’s Guide

2

• DO NOT use the instrument for any application other than calibrationwork. The instrument was designed for temperature calibration. Any otheruse of the unit may cause unknown hazards to the user.

• DO NOT use the unit in environments other than those listed in the user’sguide.

• DO NOT overfill the bath. Overflowing extremely hot fluid may be harm-ful to the operator. See Section 7.5, Filling the bath, for specific instruc-tions.

• Follow all safety guidelines listed in the user’s manual.

• Calibration Equipment should only be used by Trained Personnel.

• If this equipment is used in a manner not specified by the manufacturer,the protection provided by the equipment may be impaired.

• Before initial use, or after transport, or after storage in humid or semi-hu-mid environments, or anytime the instrument has not been energized formore than 10 days, the instrument needs to be energized for a “dry-out”period of 2 hours before it can be assumed to meet all of the safety re-quirements of the IEC 1010-1. If the product is wet or has been in a wetenvironment, take necessary measures to remove moisture prior to apply-ing power such as storage in a low humidity temperature chamber operat-ing at 50°C for 4 hours or more.

• DO NOT operate high temperature baths (500°C) near flammable materi-als. Extreme temperatures could ignite the flammable material.

• Overhead clearance is required. Do not place the instrument under a cabi-net or other structure. Always leave enough clearance to allow for safeand easy insertion and removal of probes.

• The instrument is intended for indoor use only.

• Ensure that you check the appropriate OSHA and local fire code regula-tions for proper equipment required to suppress a fire for the Salt utilizedin the bath.

BURN HAZARD

• High temperatures may be present in this equipment. Fires and severeburns may result if personnel fail to observe safety precautions.

• Ensure the bath DOES NOT contain any water and has been completelydried prior to filling with salt. Any trapped water can cause a steam explo-sion resulting in personal injury. If the bath has recently been filled withwater, ensure the inside of the drain tube is dry prior to filling the bathwith salt.

• When immersing any object in the bath, ensure that you are not introduc-ing anything into the bath that will react with the bath salt. Ensure thatprobes are DRY and free of contaminants. Read the MSDS (MaterialSafety Data Sheet) for the salt used. If you are still unsure if the materialyou are going to introduce into the bath will react with the salt, refer to

3

1 Before you startSafety information

the individual MSDS sheets for the three components that make up thesalt.

• The bath is provided with an access cover. The cover should remain onthe bath whenever possible. Operating the bath without the access coverreduces stability, increases out gassing of fluids, and increases the possi-bility of personal injury or fire hazard.

• When removing probes from the bath DO NOT wipe probes down with apaper towel. If the bath setpoint is high, the salt can cause the paper towelto ignite in your hand. Provide a safe surface and situation for the probesto cool prior to cleaning the salt from the probes.

• The bath generates extreme temperatures. Precautions must be taken toprevent personal injury or damage to objects. Probes may be extremelyhot when removed from the bath. Cautiously handle probes to preventpersonal injury. Carefully place probes on a heat resistant surface or rackuntil they are at room temperature.

• Be extremely careful when filling the bath with salt and bringing it up totemperature. Salt expands with temperature. It is easy to add salt, but ex-tremely dangerous to remove hot molten salt because the bath is overfilled. DO NOT fill the bath above the indicated fill line when the stirringis on. It will overflow.

ELECTRICAL HAZARD

• These guidelines must be followed to ensure that the safety mechanismsin this instrument will operate properly. This instrument must be pluggedinto an outlet as stated in the specifications of this guide. The power cordof the instrument is equipped with a three-pronged grounding plug foryour protection against electrical shock hazards. It must be plugged di-rectly into a properly grounded three-prong receptacle. The receptaclemust be installed in accordance with local codes and ordinances. Consulta qualified electrician. DO NOT use an extension cord or adapter plug.

• DO use a ground fault interrupt device. This unit contains a liquid. Aground fault device is advised in case liquid is present in the electricalsystem and could cause an electrical shock.

• Always replace the power cord with an approved cord of the correct rat-ing and type. If you have questions, contact an Authorized Service Center(see Section 1.3).

• High voltage is used in the operation of this equipment. Severe injury ordeath may result if personnel fail to observe the safety precautions. Beforeworking inside the equipment, turn off the power and disconnect thepower cord.

• Keep all combustible materials away from the bath when using salt. Oper-ate the bath on a heatproof surface such as concrete. Provide a means ofsafety for containing any spill, which may occur.


User’s Guide

4

BATH SALT

• Salt used in this unit may produce noxious or toxic fumes under certaincircumstances. Consult the fluid manufacturer’s MSDS (Material SafetyData Sheet). Proper ventilation and safety precautions must be observed.

• The unit is equipped with a soft cutout (user settable firmware) and a hardcutout (set at the factory). Check the flash point, boiling point, or otherfluid characteristic applicable to the circumstances of the unit operation.Ensure that the soft cutout is adjusted to the fluid characteristics of the ap-plication. Failing to set the cutout to the limits of the bath fluid can resultin fire hazards and personal injury.

1.2.2 Cautions• Always operate this instrument at room temperature between 41°F and

104°F (5°C to 40°C). Allow sufficient air circulation by leaving at least 6inches (15 cm) of clearance around the instrument.

• DO NOT overfill the bath. Overflowing liquid may damage the electricalsystem. Be sure to allow for thermal expansion of the fluid as the bathtemperature increases. See Section 7.5, Filling the bath, for specific in-structions.

• Read Section 5, Bath Use, before placing the unit into service.

• DO NOT change the values of the bath calibration constants from the fac-tory set values. The correct setting of these parameters is important to thesafety and proper operation of the unit.

• Only authorized personnel should perform the Factory Reset Sequence ifno other action is successful in correcting a malfunction. You must have acopy of the most recent Report of Test to restore the test parameters.

• DO NOT operate this instrument in an excessively wet, oily, dusty, ordirty environment.

• The bath is a precision instrument. Although it has been designed for op-timum durability and trouble free operation, it must be handled with care.Position the bath before the tank is filled with salt.

• Most probes have handle temperature limits. Be sure that the probe handletemperature limit is not exceeded in the air above the instrument.

• The instrument and any thermometer probes used with it are sensitive in-struments that can be easily damaged. Always handle these devices withcare. Do not allow them to be dropped, struck, stressed, or overheated.

• DO ensure the salt is cleaned from the probes prior to immersing theprobe in the next bath. Clean your probe between each bath to avoid con-tamination between bath fluids.

• Under filling the bath may reduce the bath performance and may possiblydamage the bath.

• When calibrating PRTs always follow correct calibration procedure andcalibrate from high temperatures to low temperatures with the appropriate

5

1 Before you startSafety information

triple point of water checks. Never immerse a wet or cold PRT into a bathfilled with hot fluid. Severe damage to the PRT may result as well as per-sonal injury to the calibration technician.

• This bath is not designed to be portable. Therefore, moving the bath onceit has been installed should be kept to a minimum. NEVER MOVE ABATH THAT IS FULL OF HOT FLUID. This action could be ex-tremely dangerous and could result in personal injury to the person mov-ing the bath. The fluid can splash causing injury or if the bath tips, the hotfluid could cause damage to the surrounding area and personnel.

• If the bath must be moved, allow the salt to solidify and cool. Care mustbe used when moving the bath with the fluid solidified in the bath. Thecontrol probe can easily be damaged. Four people are required to safelymove the bath.

• The control probe must be inserted through the lid into the bath fluid andplugged into the socket at the back of the bath. DO NOT operate the bathwithout the control probe properly inserted and attached. The bath willnot operate correctly without the control probe. Injury to operating per-sonnel and permanent damage to the bath could occur.

1.3 Authorized Service CentersPlease contact one of the following authorized Service Centers to coordinateservice on your Hart product:

Fluke, Hart Scientific Division

799 E. Utah Valley Drive

American Fork, UT 84003-9775

USA

Phone: +1.801.763.1600

Telefax: +1.801.763.1010

E-mail: [email protected]

Fluke Nederland B.V.

Customer Support Services

Science Park Eindhoven 5108

5692 EC Son

NETHERLANDS

Phone: +31-402-675300

Telefax: +31-402-675321



User’s Guide

6

Fluke Int'l Corporation

Service Center - Instrimpex

Room 2301 Sciteck Tower

22 Jianguomenwai Dajie

Chao Yang District

Beijing 100004, PRC

CHINA

Phone: +86-10-6-512-3436

Telefax: +86-10-6-512-3437


Fluke South East Asia Pte Ltd.

Fluke ASEAN Regional Office

Service Center

60 Alexandra Terrace #03-16

The Comtech (Lobby D)

118502

SINGAPORE

Phone: +65 6799-5588

Telefax: +65 6799-5588


When contacting these Service Centers for support, please have the followinginformation available:

• Model Number

• Serial Number

• Voltage

• Complete description of the problem

7

1 Before you startAuthorized Service Centers

2 Introduction

The 6055 Calibration Bath is a highly stable constant temperature salt bath. Ithas been designed for calibrating liquid-in-glass thermometers or other types oflong thermometers against a known temperature standard such as a StandardPlatinum Resistance Thermometer (SPRT).

The 6055 calibration bath provides the following features:

• A deep fluid tank (test well is 3.88 inches in diameter and has 17 inchesof fluid depth).

• A highly temperature stable low gradient environment typically a nominalstability of ±0.005°C with salt. The fluid is well stirred and environmen-tally protected to minimize gradients.

• The fluid level is near the top of the test well to facilitate calibration ofliquid-in-glass thermometers without needing to compensate for stem ef-fect.

• The bath provides two calibration modes; temperature control mode andtemperature drift mode. The temperature control mode uses a hybrid digi-tal and analog PI controller with lock in amplifier design. The temperatureand other functions are selected with the four button keypad to a hun-dredth of a degree and finer with a digital vernier adjustment. The Driftmode bypasses the controller with heater power manually controlled bythe variable transformer.

9

2 Introduction

3 Specifications and environmentalconditions

3.1 Specifications

Range 200 °C to 550 °C (392 °F to 1022 °F)

Stability ± 0.003 °C at 200 °C (salt)± 0.010 °C at 550 °C (salt)

Uniformity ± 0.005 °C at 200 °C (salt)± 0.010 °C at 550 °C (salt)

Temperature Setting Digital display with push-button entry

Set-Point Resolution 0.01 °C, high resolution 0.00018 °C

Display TemperatureResolution

0.01 °C

Digital Setting Accuracy ± 1 °C

Digital Setting Repeatability ± 0.01 °C

Heaters 260 to 2080 W

Working Area 107 mm diameter (4.2 in), 432 mm deep (17 in), removable SST lid,special viewing channel for LIG sighting

Wetted Parts 304 stainless steel

Power 230 V ac (± 10 %), 50/60 Hz, 15 A

Volume 19.8 liters, 43 kg of bath salt (5.2 gal, 95 lb)

Size 57.2 cm D x 77.5 cm W x 152.4 cm H (22.5 x 30.5 x 60 in)

Weight 70.8 kg (156 lb)

Distance from Line of Sight toTop of Fluid

15.9 mm (5/8 in)

Safety OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2per IEC1010-1

3.2 Environmental conditionsAlthough the instrument has been designed for optimum durability and trou-ble-free operation, it must be handled with care. The instrument should not beoperated in an excessively dusty or dirty environment. Maintenance and clean-ing recommendations can be found in the Maintenance Section of this manual.

The instrument operates safely under the following conditions:

• ambient temperature range: 5–50°C (41–122°F)

• ambient relative humidity: maximum 80% for temperature <31°C, de-creasing linearly to 50% at 40°C

• pressure: 75kPa–106kPa

11

3 Specifications and environmental conditionsSpecifications

• mains voltage within ±10% of nominal

• vibrations in the calibration environment should be minimized

• altitude less than 2000 meters


User’s Guide

12

4 Installation

CAUTION: READ SECTION 5 ENTITLED BATH USE before placing thebath in service. Incorrect handling can damage the bath and void the war-ranty.

This section provides the steps required to set up and operate the 6055 bath.This section should be used as a general overview and reference and not as asubstitute for the remainder of the manual. Please read Sections5 through7carefully before operating the bath.

WARNING: Never move a bath that is full of “hot” fluid. This action isextremely dangerous and can result in personal injury and possible dam-age to the surrounding area.

The bath comes on a cart. This cart is for ease of operation, but in no way im-plies that the bath is portable. This bath is extremely dangerous when filledwith salt. Follow the safety guidelines set forth in the Before you start section.

The bath should never be picked up with liquid salt in the tank. If the bathneeds to be picked up, allow the salt to solidify and cool. Four people areneeded to safely lift the bath. Lift the bath where the bath and the cart meet.

CAUTION: Use caution as this bath is top heavy.

4.1 UnpackingUnpack the bath carefully and inspect it for any damage that may have oc-curred during shipment. If there is shipping damage, notify the carrierimmediately.

Verify that the following components are present:

• 6055 Bath

• Control Probe

• Power Cord

• Immersion Heater

• Report of Test

• Carousel (optional)

13

4 InstallationUnpacking

4.2 Comments concerning the use of salt

CAUTION: Do not use the control heaters to melt granular salt when fill-ing the bath. The control heaters can be damaged if used in such a man-ner. Use the immersion heater (with a power of about 1000 watts) to meltthe salt. Do not turn the POWER on until the tank is 3/4 full of melted salt.

4.3 Bath environmentThe Model 6055 bath is a precision instrument that must be located in an ap-propriate environment. The location should be free from drafts, extreme tem-peratures, extreme temperature changes, and dirt. Use the levelers to ensure thatthe bath is level. Allow free air space around the bath to allow surface heat toconvect away freely. A fume hood should be used for ventilation of fumes.

Because the bath is designed for operation at high temperatures, keep all flam-mable and meltable materials away from the bath. Although the bath is well in-sulated, top surfaces do become hot. Beware of the danger of accidental fluidspills.

If used at high temperatures, a fume hood should be used to remove any vaporsgiven off by hot bath fluid.

4.4 “Dry-out” periodThe melting period for salt serves as a “dry-out” period for the heaters of thisbath. During this time period all of the safety requirements of the IEC 1010-1CAN NOT be assumed to be met.

4.5 PowerPlug the bath power cord into a mains outlet of the proper voltage, frequency,and current capability as stated in the Specifications. Set the “HEATER” switchon the front panel to position “LOW” and turn the bath on using the front panel“POWER” switch. The bath turns on and begins to heat or cool to reach thepreviously programmed temperature set-point. The front panel LED display in-dicates the actual bath temperature.

4.6 SetupThe probe used with the Model 6055 is a precision PRT sensor. The probeshould not be bent or damaged in any way. Plug the probe into the probe con-nector on the rear panel of the bath.

Plug the stirrer into the receptacle marked “STIRRER POWER” located on therear panel of the bath. This receptacle is switched on with the instruments con-trol after the instrument reaches 200°C.


User’s Guide

14

4.7 Setting the temperatureIn the following discussion and throughout this manual a solid box around theword SET, UP, EXIT, or DOWN indicates the panel button while the dotted boxindicates the display reading. Explanation of the button or display reading areto the right of each button or display value.

To view or set the bath temperature set-point proceed as follows. The frontpanel LED display normally shows the actual bath temperature.

100.00 C Bath temperature display

When “SET” is pressed the display shows the set-point memory that is cur-rently being used and its value. Eight set-point memories are available.

S Access set-point selection

1. 150.0 Set-point 1, 150.0 °C currently used

Press “SET” to select this memory and access the set-point value.

S Access set-point value

C 150.00 Current value of set-point 1, 150.00°C

Press “UP” or “DOWN” to change the set-point value.

U Increment display

C 160.00 New set-point value

Press “SET” to accept the new value and display the vernier value. The bath be-gins heating or cooling to the new set-point.

S Store new set-point, access vernier

0.00000 Current vernier value

Press “EXIT” and the bath temperature will be displayed again.

E Return to the temperature display

100.00 C Bath temperature display

15

4 InstallationSetting the temperature

The bath heats or cools until it reaches the new set-point temperature. Set theheater switch to position “HIGH” to allow the bath to more quickly reach ahigher temperature. The “HIGH” setting may be necessary to reach higher tem-peratures and control at high temperatures.

When setting the set-point temperature be careful not to exceed the temperaturelimit or the bath fluid. The over-temperature cut-out should be correctly set toprevent this from happening. See Section 8.8.

To obtain optimum control stability adjust the proportional band as discussed inSection 8.7.


User’s Guide

16

5 Bath Use

CAUTION: READ THIS SECTION before placing the bath in service.Incorrect handling can damage the bath and void the warranty.

The information in this section is for general information only. It is not de-signed to be the basis for calibration laboratory procedures. Each laboratorywill need to write their own specific procedures.

5.1 GeneralBe sure to select the correct fluid for the temperature range of the calibration.Bath fluids should be selected to operate safely with adequate thermal proper-ties to meet the application requirements. Also, be aware that some fluids ex-pand and could overflow the bath if not watched. Refer to General Operation,Section 7, for information specific to fluid selection and to the MSDS sheetspecific to the fluid selected. Generally, baths are set to one temperature andused to calibrate probes only at that single temperature. This means that thetype of bath fluid does not have to change. Additionally, the bath can be left en-ergized reducing the stress on the system.

The bath generates extreme temperatures. Precautions must be taken to preventpersonal injury or damage to objects. Probes may be extremely hot or coldwhen removed from the bath. Cautiously handle probes to prevent personal in-jury. Carefully place probes on a heat/cold resistant surface or rack until theyare at room temperature. It is advisable to wipe the probe with a clean soft clothor paper towel before inserting it into another bath. This prevents the mixing offluids from one bath to another. If the probe has been calibrated in liquid salt,carefully wash the probe in warm water and dry completely before transferringit to another fluid. Always be sure that the probe is completely dry before in-serting it into a hot fluid. Some of the high temperature fluids react violently towater or other liquid mediums. Be aware that cleaning the probe can be danger-ous if the probe has not cooled to room temperature. Additionally, high temper-ature fluids may ignite the paper towels if the probe has not been cooled.

For optimum accuracy and stability, allow the bath adequate stabilization timeafter reaching the set-point temperature.

5.2 Comparison calibrationComparison calibration involves testing a probe (unit under test, UUT) againsta reference probe. After inserting the probes to be calibrated into the bath, al-low sufficient time for the probes to settle and the temperature of the bath tostabilize.

One of the significant dividends of using a bath rather than a dry-well to cali-brate multiple probes is that the probes do not need to be identical in construc-tion. The fluid in the bath allows different types of probes to be calibrated at

17

5 Bath UseGeneral

the same time. However, stem effect from different types of probes is not to-tally eliminated. Even though all baths have horizontal and vertical gradients,these gradients are minimized inside the bath work area. Nevertheless, probesshould be inserted to the same depth in the bath liquid. Be sure that all probesare inserted deep enough to prevent stem effect. From research at Hart Scien-tific, we suggest a general rule-of-thumb for immersion depth to reduce thestem effect to a minimum: 15 x the diameter of the UUT + the sensor length.Do not submerge the probe handles. If the probe handles get too warm dur-ing calibration at high temperatures, a heat shield could be used just below theprobe handle. This heat shield could be as simple as aluminum foil slid over theprobe before inserting it in the bath or as complicated as a specially designedreflective metal apparatus.

When calibrating over a wide temperature range, better results can generally beachieved by starting at the highest temperature and progressing down to thelowest temperature.

Probes can be held in place in the bath by using probe clamps or drilling holesin the access cover. Other fixtures to hold the probes can be designed. The ob-ject is to keep the reference probe and the probe(s) to be calibrated as closelygrouped as possible in the working area of the bath. Bath stability is maximizedwhen the bath working area is kept covered.

In preparing to use the bath for calibration start by:

• Placing the reference probe in the bath working area.

• Placing the probe to be calibrated, the UUT, in the bath working area asclose as feasibly possible to the reference probe.

5.3 Calibration of multiple probesFully loading the bath with probes increases the time required for the tempera-ture to stabilize after inserting the probes. Using the reference probe as theguide, be sure that the temperature has stabilized before starting the calibration.


User’s Guide

18

6 Parts and controls

This section describes the Front Panel, the Power Panel, and the Back Panel ofthe 6055.

The Front Panel, located just left of the bath, consists of the Controller Panel(Figure 1) and the Power Panel (Figure 2).

6.1 Controller panelThe Controller Panel includes: 1) the digital LED display, 2) the control buttonsand 3) the control indicator light.

1) The digital LED display is an important part of the temperature control-ler because it not only displays set and actual temperatures but also dis-plays various controller functions, settings, and constants. The displayshows temperatures in values according to the selected scale °C or °F.

2) The control buttons (SET, DOWN, UP, and EXIT) are used to set thetemperature set-point, access and set other operating parameters, and ac-cess and set calibration parameters.

The functions of the buttons are as follows:

SET - Used to display the next parameter in the menu and to set parameters tothe displayed value.

DOWN - Used to decrement the displayed value of parameters.

UP - Used to increment the displayed value.

EXIT - Used to exit from a menu. When “EXIT” is pressed any changes madeto the displayed value will be ignored.

3) The control indicator is a two color light emitting diode (LED). This in-dicator lets the user visually see the ratio of heating to cooling. When theindicator is red the heater is on, and when it is green the heater is off andthe bath is cooling.

19

6 Parts and controlsController panel

SET

HEATERMODE

DOWN UP EXIT

6055 HIGH PRECISION BATH 200°C to 550°C

13

2

550.00 C

Figure 1 Controller panel

6.2 Power panelThe Power Panel (Figure 2) controls include: 1) the power switch and indicator,2) the boost heater and indicator, 3) the mode select switch and indicators, 4)the control heating select switch, and 5) the drift adjust control.

1) The “ON/OFF” power switch powers up the bath. The switch is a DPSTtype that opens both legs of the ac mains power source. A red indicatorlight shows that power is on.

2) The boost heating provides an additional 900 watts for rapidly changingbetween temperatures. The boost heating indicator shows whether theboost heater is on or off. The boost heater is powered through the tem-perature controller triac to prevent exceeding the desired set temperature.The boost heater indicator flashes when the set temperature has beenreached as a reminder to turn it off for control.

3) The mode select switch selects between the Temperature Control andTemperature Drift modes. The indicator light shows which mode is func-tioning. The Temperature Control position selects the temperature con-troller panel. In Temperature Drift mode, the heater control is via theDrift Adjust control and the heating select switch.

4) The control heating switch selects the control heater power positions; offthrough 4. Select the lowest reasonable value for normal control condi-


User’s Guide

20

50

60

70

80

90

100

40

30

20

10

0PERCENT

DRIFT ADJUSTMODE SELECT

TEMPERATURE CONTROL

TEMPERATURE DRIFT

HEATINGPOWER

LOW

HIGH

ON

OFF

BOOSTHEATER

OFF

OFF

Boost HeatingIndicator

PowerIndicator

PowerSwitch

HeatingSwitch

Temperature ControlMode Indicator

Boost HeatingSwitch

Mode SelectSwitch

Temperature DriftMode Indicator

Drift AdjustControl

1

2 3

4

5

Figure 2 Power panel

21

6 Parts and controlsPower panel

1

6

7

8

2

54

Figure 3 Back panel

tions depending on bath temperature. The switch simply adds more heat-ers into the circuit until the desired power is attained. Position 2 isvariable using the Drift Adjust control.

5) The drift adjust control is a variable transformer that adjusts the position1 control heater through 0 to 100% of its power range. The additionalpower required for higher temperatures may be added in steps by select-ing heating 2, 3, 4, etc. Positions 2 + 3 + 4 + 5 will not achieve the maxi-mum possible temperatures. Boost + 2 is the next increment. Boost + 2 +3 and so on can be used as required.

6.3 Back panelThe Back Panel (Figure 3) includes: 1) the probe connector, 2) the stirrer poweroutlet, 4) the power cord, 5) the heater power connector, 6) the serial number,7) optional RS-232 connector, and 8) optional IEEE-488 GPIB connector.

1) The probe connector on the back panel is used for the temperature con-troller probe.

2) The stirrer power connection provides ac power to the stirring motor andcooling fan.

3) The system fuses are internal (one fuse for each leg of the ac mainspower). Only replace fuses with those of the same rating and type.

4) The power cord.

5) The heater power outlet supplies power to the control and boost heatersthat are attached to the top plate of the bath tank. The connector allowsthe assembly to be easily removed if required.

6) The serial number is located at the top right corner of the back panel.When consulting with an Authorized Service Center, refer to the serialnumber.

7) Optional DB-9 connector for interfacing the instrument to a computer orterminal with a serial RS-232 cable.

8) Optional GPIB connector for interfacing the instrument to a computer orterminal using IEEE-488 communications.


User’s Guide

22

7 General operation

The components, features and operational theory of the Model 6055 calibrationbath are described in this section.

The Model 6055 calibration bath is shown in block diagram form in Figure 4on page 24. This diagram illustrates the primary features of the bath system andtheir function, which are described as follows.

7.1 Two modes of temperature controlThere are two modes of temperature control available with the Model 6055.The Temperature Control mode or the Temperature Drift mode may be selectedby a switch on the front panel.

7.1.1 Temperature control modeThe Temperature Control Mode uses a hybrid digital/analog PI temperaturecontroller with a lock-in-amplifier. The bath stability is very high with this con-troller. The temperature is selected using the four button keypad on the frontpanel. Temperatures from 150 to 550°C may be selected directly to a hundredthof a degree. Finer adjustment is available using the vernier adjustment. Accu-racy of the setting is typically ±0.5°C or better.

The controller pulses AC current to the control heaters in a time modulatedfashion to compensate for heat gains and losses to the system. A two color LEDon the control panel glows red when the heaters are on and glows green whenthey are off and cooling is taking place. (Note: The cooling required for controlis supplied through heat loss to ambient).

The temperature control probe uses a 100 ohm PRT. Plug the probe into therear of the control unit.

The heaters are internal to the tank. They are arranged electrically to providethe 4 control heating positions plus an off position. The additional boost heat-ing position is accessed from a separate switch on the control panel.

7.1.2 Temperature drift modeWhen using the Temperature Drift mode, the heater may be set manually to al-low the temperature to drift very slowly (a few millidegrees C per minute) overthe desired range. This allows the control noise to be eliminated althoughgreater skill is required in making calibrations. The heater power is adjusted bymeans of a variable transformer located on the control panel. It allows positionone of the heater selection switch to be continually variable from 0 to 100%.Positions 2, 3, 4 and Boost add their full value of heat incrementally to the ad-justed value of position 1.

23

7 General operationTwo modes of temperature control


User’s Guide

24

OFF

DIGI

TAL D

ISPL

AY

315.0

0 CCO

NSTA

NT LE

VEL

17" D

EEP

3.88"

DIA

BATH

TANK

FLOW

TEST

WEL

LIN

DICA

TOR

CONT

ROL

HI

TRAN

SFOR

MER

VARI

ABLE

CONT

ROL M

ODE

DRIFT

MOD

E

FLUI

DTA

NKIN

SULA

TED

HEAT

ING

SELE

CTMO

DE

DRAI

N

STIR

RER

COOO

LING

FAN

BOOS

THE

ATER

PROB

E

ADJU

STDR

IFTCONT

ROLL

ERTE

MPER

ATUR

E

WA

RN

ING

: DR

AIN

IS F

OR

FA

CTO

RY

US

E O

NLY

!

Figure 4 System diagram

7.2 Bath fluidHeat transfer salt works with the 6055 bath up to 550°C. Other fluidsSHOULD NOT be used with the 6055 bath.

7.3 Fluid systemThe fluid system consists of the insulated tank, the stirrer assembly, the drain,the overflow test well, and the fluid. The heaters and probe, which are part ofthe control system, are physically internal to the tank.

The tank and other wetted parts are made of stainless steel. The stirrer is at-tached to the tank top plate of the bath and its motor receives additional coolingfrom a fan to keep from overheating and to increase the lifetime at high bathtemperatures. The stirrer directly drives three 2-inch diameter stirring propel-lers. The down draft from the propellers forces the fluid through the overflowtest well. The stirring motor plugs into the rear of the control unit. (See Figure5 on page 26.)

The over-flow test well serves to provide a constant depth of fluid at an essen-tially constant height near the well opening. Variations in fluid volume due tothermal expansion and evaporation do not effect measurements within reason-able volume ranges. The fluid expelled from the tank is controlled to flow pastthe control heaters first before entering the main tank for thermal management.

WARNING: The drain is for factory use only.

7.4 Fluid DrainThe drain on the bottom of the bath (see Figure 4 on page 24) is for factory useonly. During operation of the bath the drain plug must be screwed on tightly.

7.5 Filling the bathThe bath is shipped dry. Check inside of the test well for foreign matter and re-move it to avoid interference with operation.

7.5.1 Using heat transfer salt

7.5.1.1 The first salt load

Salt comes in small bead or granular form which is initially pink in color. Ap-proximately 70 pounds are required for the installation.

The following procedure is required if the bath is empty and will be filled withbead or granular salt.

25

7 General operationBath fluid


User’s Guide

26

Figure 5 System diagram

• Use an immersion heater (with a power of about 1000 watts) to melt thesalt.

• Do not use the control heaters to melt the granular salt or they will bedamaged.

• Inspect the drain to be sure it is fully sealed.

• Insert the immersion heater into the test well and fill the remaining spacewith the granular salt.

• As the salt melts, it will run into the main tank. As this occurs continuallyfill the test well with more salt.

CAUTION: Danger of serious burns exists. Use extreme care and use ap-propriate safety equipment.

As this process continues and the tank is nearing its full level, turn the POWERswitch ON and set the temperature to about 200°C with the MODE SELECTswitched to TEMPERATURE CONTROL. The stirrer will not turn on until thebath has actually reached the cut in temperature of 175 to 225°C. The meltingpoint of the salt is about 150°C. Increase the temperature of the main tank andadd more salt until the salt depth reaches about 3.5 inches from the tank topplate at 250°C (without pumping).

7.5.1.2 Melting the salt

The following process is to be followed to melt salt in a bath which has previ-ously had salt installed and has cooled.

• Turn on the unit and set the temperature to the desired starting point (atleast 200°C).

• Turn the heater to the maximum position of 4 and turn on the boostheater.

• The controller will limit the duty cycle of the heaters to 25% until the saltreaches about 200°C.

• As the heat expands the solid salt, you will hear some cracking noiseswhich should not cause concern.

• When the stirrer cut in temperature is reached the stirrer will turn on andbegin to pump the molten salt into the test well.

• If the thermometer holding fixture was removed previously, it may be re-placed at this time.

• The bath is now ready for operation.

27

7 General operationFilling the bath

7.6 StirringStirring of the bath salt is very important for stable temperature control. Thesalt must be mixed well for good temperature uniformity and fast controller re-sponse. The stirrer is precisely adjusted for optimum performance.

7.7 PowerPower to the bath is provided by an AC mains supply as specified in the speci-fications. Power to the bath passes through a filter to prevent switching spikesfrom being transmitted to other equipment.

To turn on the bath switch the control panel power switch to the “ON” position.The stir motor will turn on, the LED display will begin to show the bath tem-perature, and the heater will turn on or off until the bath temperature reachesthe programmed set-point.

When powered on the control panel display will briefly show a four digit num-ber. This number indicates the number of times power has been applied to thebath. Also briefly displayed is data which indicates the controller hardwareconfiguration. This data is used in some circumstances for diagnostic purposes.


User’s Guide

28

8 Controller operation

This section discusses in detail how to operate the bath temperature controllerusing the front control panel. Using the front panel key switches and LED dis-play the user may monitor the bath temperature, set the temperature set-point indegrees C or F, monitor the heater output power, adjust the controller propor-tional band, set the cut-out set-point, and program the probe calibration param-eters, operating parameters, optional serial and IEEE-488 interfaceconfiguration, and controller calibration parameters. Operation of the primaryfunctions is summarized in Figure 6.

8.1 Bath temperatureThe digital LED display on the front panel allows direct viewing of the actualbath temperature. This temperature value is what is normally shown on the dis-play. The units, C or F, of the temperature value are displayed at the right. Forexample,

25.00 C Bath temperature in degrees Celsius

The temperature display function may be accessed from any other function bypressing the “EXIT” button.

8.2 Reset cut-outIf the over-temperature cut-out has been triggered then the temperature displaywill alternately flash,

Cut-out Indicates cut-out condition

The message continues to flash until the temperature is reduced and the cut-outis reset.

The cut-out has two modes — automatic reset and manual reset. The mode de-termines how the cut-out is reset which allows the bath to heat up again. Whenin automatic mode, the cut-out resets itself as soon as the temperature is low-ered below the cut-out set-point. With manual reset mode the cut-out must bereset by the operator after the temperature falls below the set-point.

When the cut-out is active and the cut-out mode is set to manual (“reset”) thenthe display flashes “Cut-out” until the user resets the cut-out. To access thereset cut-out function press the “SET” button.

S Access cut-out reset function

The display indicates the reset function.

29

8 Controller operationBath temperature


User’s Guide

30

SET/EXIT

CalibrationMenu

CTO

Adjust CTO

C0

Adjust C0

CG

Adjust CG

H

Adjust H

L

Adjust L

SET/EXIT

IEEE-488Interface

Menu

DeviceAddress

Adj. DeviceAddress

UP UP UP UP

DOWN DOWN DOWN DOWN

SET SET SET SET

SET/EXIT

SET/EXIT

OperatingParameters

Menu

SET

EXIT EXIT EXIT

EXIT

EXIT

EXIT

EXIT

EXIT

EXIT

EXIT

EXIT

EXIT

EXIT

EXIT

EXIT

EXITSET SET SET

SET

SET

SET

SET

SET

SET

SET

SET

SET

SET

SET

SET

SET

SET/EXIT SET/EXIT

SET/EXIT SET/EXIT SET/EXIT SET/EXIT

SET/EXIT

SET/EXIT

SET/EXIT

SET/EXIT

SET/EXIT

ProbeMenu

R0

ALPHA

Adj. R0

Adj. ALPHA

SET/EXIT

SerialInterface

Menu

BAUDRate

AdjustBAUD Rate

SamplePeriod

Adj. SamplePeriod

DuplexMode

Adj. DuplexMode

Linefeed

AdjustLinefeed

EXITEXITEXIT EXIT EXIT

EXIT

EXIT

EXIT

EXIT

EXITSET +

Display Power

Set Proportional Band

Set Cutout Temp.

EXIT

EXIT

EXIT

SET

SET

SET

SET

SET

SET

SET

SET

SET

SET

Reset Cutout

Select Setpoint

Adjust Setpoint

EXIT

EXIT Adjust Vernier

Set Scale °C/°F

Cutout Active

DisplayTemperature

CutoutReset Mode

StirrerMode Select

StirrerSetpoint

HeatupPower

Adj. CutoutReset Mode

Adj. StirrerMode

Adj. StirrerSetpoint

Adj. HeatupPower

X 5

DO

NO

T C

HA

NG

ET

HE

SE

VAL

UE

S. S

EE

MA

NU

AL

Configuration Menu

Secondary Functions

IEEE-488Option Installed

InterfaceOption Installed

Figure 6 Controller operation flowchart

rESEt ? Cut-out reset function

Press “SET” once more to reset the cut-out.

S Reset cut-out

This will also switch the display to the set temperature function. To return todisplaying the temperature press the “EXIT” button. If the cut-out is still in theover-temperature fault condition the display continues to flash “cut-out”.The bath temperature must drop a few degrees below the cut-out set-point be-fore the cut-out can be reset.

8.3 Temperature set-pointThe bath temperature can be set to any value within the range as given in thespecifications with a high degree of resolution. The temperature range of theparticular fluid used in the bath must be known by the operator and the bathshould only be operated well below the upper temperature limit of the liquid. Inaddition, the cut-out temperature should also be set below the upper limit of thefluid.

Setting the bath temperature involves three steps: (1) select the set-point mem-ory, (2) adjust the set-point value, and (3) adjust the vernier, if desired.

8.3.1 Programmable set-pointsThe controller stores 8 set-point temperatures in memory. The set-points can bequickly recalled to conveniently set the bath to a previously programmedtemperature.

To set the bath temperature one must first select the set-point memory. Thisfunction is accessed from the temperature display function by pressing “SET”.The number of the set-point memory currently being used is shown at the lefton the display followed by the current set-point value.

25.00 C Bath temperature in degrees Celsius

S Access set-point memory

1. 25.0 Set-point memory 1, 25.0°C currently used

To change the set-point memory press “UP” or “DOWN”.

U Increment memory

4. 40.0 New set-point memory 4, 40.0°C

Press “SET” to accept the new selection and access the set-point value.

31

8 Controller operationTemperature set-point

S Accept selected set-point memory

8.3.2 Set-point valueThe set-point value may be adjusted after selecting the set-point memory andpressing “SET”. The set-point value is displayed with the units, C or F, at theleft.

C 40.00 Set-point 4 value in°C

If the set-point value need not be changed then press “EXIT” to resume dis-playing the bath temperature. To adjust the set-point value press “UP” or“DOWN”.

U Increment display

C 42.50 New set-point value

When the desired set-point value is reached press “SET” to accept the newvalue and access the set-point vernier. If “EXIT” is pressed instead then anychanges made to the set-point will be ignored.

S Accept new set-point value

8.3.3 Set-point vernierThe set-point value can be set with a resolution of 0.01°C. The user may wantto adjust the set-point slightly to achieve a more precise bath temperature. Theset-point vernier allows one to adjust the temperature below or above theset-point by a small amount with very high resolution. Each of the 8 storedset-points has an associated vernier setting. The vernier is accessed from theset-point by pressing “SET”. The vernier setting is displayed as a 6 digit num-ber with five digits after the decimal point. This is a temperature offset in de-grees of the selected units, C or F.

0.00000 Current vernier value in°C

To adjust the vernier press “UP” or “DOWN”. Unlike most functions the ver-nier setting has immediate effect as the vernier is adjusted. “SET” need not bepressed. This allows one to continually adjust the bath temperature with thevernier as it is displayed.

U Increment display

0.00090 New vernier setting


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Next press “EXIT” to return to the temperature display or “SET” to access thetemperature scale units selection.

S Access scale units

8.4 Temperature scale unitsThe temperature scale units of the controller may be set by the user to degreesCelsius (°C) or Fahrenheit (°F). The units will be used in displaying the bathtemperature, set-point, vernier, proportional band, and cut-out set-point.

The temperature scale units selection is accessed after the vernier adjustmentfunction by pressing “SET”. From the temperature display function access theunits selection by pressing “SET” 4 times.

25.00 C Bath temperature

S Access set-point memory

1. 25.0 Set-point memory

S Access set-point value

C 25.00 Set-point value

S Access vernier

0.00000 Vernier setting

S Access scale units selection

Un= C Scale units currently selected

Press “UP” or “DOWN” to change the units.

U Change units

Un= F New units selected

Press “SET” to accept the new selection and resume displaying the bathtemperature.

S Set the new units and resume temperature display

33

8 Controller operationTemperature scale units

8.5 Secondary menuFunctions which are used less often are accessed within the secondary menu.The secondary menu is accessed by pressing “SET” and “EXIT” simulta-neously and then releasing. The first function in the secondary menu is theheater power display. (See Figure 6.)

8.6 Heater powerThe temperature controller controls the temperature of the bath by pulsing theheater on and off. The total power being applied to the heater is determined bythe duty cycle or the ratio of heater on time to the pulse cycle time. This valuemay be estimated by watching the red/green control indicator light or read di-rectly from the digital display. By knowing the amount of heating the user cantell if the bath is heating up to the set-point, cooling down, or controlling at aconstant temperature. Monitoring the percent heater power lets the user knowhow stable the bath temperature is. With good control stability the percent heat-ing power should not fluctuate more than ±1% within one minute.

The heater power display is accessed in the secondary menu. Press “SET” and“EXIT” simultaneously and release. The heater power will be displayed as apercentage of full power.

S+E Access heater power in secondary menu

12 Pct Heater power in percent

To exit out of the secondary menu press “EXIT”. To continue on to the propor-tional band setting function press “SET”.

E Return to temperature display

8.7 Proportional bandIn a proportional controller such as this the heater output power is proportionalto the bath temperature over a limited range of temperatures around theset-point. This range of temperature is called the proportional band. At the bot-tom of the proportional band the heater output is 100%. At the top of the pro-portional band the heater output is 0. Thus as the bath temperature rises theheater power is reduced, which consequently tends to lower the temperatureback down. In this way the temperature is maintained at a fairly constanttemperature.

The temperature stability of the bath depends on the width of the proportionalband. See Figure 7. If the band is too wide the bath temperature will deviate ex-cessively from the set-point due to varying external conditions. This is becausethe power output changes very little with temperature and the controller cannotrespond very well to changing conditions or noise in the system. If the propor-


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tional band is too narrow the bath temperature may swing back and forth be-cause the controller overreacts to temperature variations. For best controlstability the proportional band must be set for the optimum width.

The optimum proportional band width depends on several factors among whichare fluid volume, fluid characteristics (viscosity, specific heat, thermal conduc-tivity), operating temperature, and stirring. Thus the proportional band widthmay require adjustment for best bath stability when any of these conditionschange. Of these, the most significant factors affecting the optimum propor-tional band width are the fluid viscosity and thermal noise due to difference intemperature between the fluid and ambient. The proportional band should bewider when the fluid viscosity is higher because of the increased response timeand also when noise is greater.

The proportional band width is easily adjusted from the bath front panel. Thewidth may be set to discrete values in degrees C or F depending on the selectedunits. The optimum proportional band width setting may be determined bymonitoring the stability with a high resolution thermometer or with the control-ler percent output power display. Narrow the proportional band width to thepoint at which the bath temperature begins to oscillate and then increase theband width from this point to 3 or 4 times wider.

The proportional band adjustment may be accessed within the secondary menu.Press “SET” and “EXIT” to enter the secondary menu and show the heaterpower. Then press “SET” to access the proportional band.



S Access proportional band

35

8 Controller operationProportional band

Proportional Band too Narrow Proportional Band too Wide

Optimum Proportional Band

Figure 7 Bath temperature fluctuations at various proportional band settings

Pb=0.101C Proportional band setting

To change the proportional band press “UP” or “DOWN”.

D Decrement display

Pb=0.060C New proportional band setting

To accept the new setting and access the cut-out set-point press “SET”. Press-ing “EXIT” will exit the secondary menu ignoring any changes just made to theproportional band value.

S Accept the new proportional band setting

8.8 Cut-outAs a protection against software or hardware fault, shorted heater triac, or usererror, the bath is equipped with an adjustable heater cut-out device that willshut off power to the heater if the bath temperature exceeds a set value. Thisprotects the heater and bath materials from excessive temperatures and, mostimportantly, protects the bath fluids from being heated beyond the safe operat-ing temperature preventing hazardous vaporization, breakdown, or ignition ofthe liquid. The cut-out temperature is programmable by the operator from thefront panel of the controller. It must always be set below the upper temperaturelimit of the fluid and no more than 10 degrees above the upper temperaturelimit of the bath.

If the cut-out is activated because of excessive bath temperature then power tothe heater will be shut off and the bath will cool. The bath will cool until itreaches a few degrees below the cut-out set-point temperature. At this point theaction of the cut-out is determined by the setting of the cut-out mode parameter.The cut-out has two modes — automatic reset or manual reset. If the mode isset to automatic, then the cut-out will automatically reset itself when the bathtemperature falls below the reset temperature allowing the bath to heat upagain. If the mode is set to manual, then the heater will remain disabled untilthe user manually resets the cut-out.

The cut-out set-point may be accessed within the secondary menu. Press “SET”and “EXIT” to enter the secondary menu and show the heater power. Thenpress “SET” twice to access the cut-out set-point.



S Access proportional band


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Pb=0.101C Proportional band setting

S Access cut-out set-point

CO= 210C Cut-out set-point

To change the cut-out set-point press “UP” or “DOWN”.

D Decrement display

CO= 95C New cut-out set-point

To accept the new cut-out set-point press “SET”.

S Accept cut-out set-point

The next function is the configuration menu. Press “EXIT” to resume display-ing the bath temperature.

8.9 Controller configurationThe controller has a number of configuration and operating options and calibra-tion parameters which are programmable via the front panel. These are ac-cessed from the secondary menu after the cut-out set-point function by pressing“SET”. The display will prompt with “COnFIG”. Press “SET” once more.There are 5 sets of configuration parameters — probe parameters, operating pa-rameters, serial interface parameters, IEEE-488 interface parameters, and con-troller calibration parameters. The menus are selected using the “UP” and“DOWN” keys and then pressing “SET”. See Figure 6.

8.10 Probe parametersThe probe parameter menu is indicated by,

PrObE Probe parameters menu

Press “SET” to enter the menu. The probe parameters menu contains the pa-rameters, R0 and ALPHA, which characterize the resistance-temperature rela-tionship of the platinum control probe. These parameters may be adjusted toimprove the accuracy of the bath. This procedure is explained in detail in Sec-tion 10.

The probe parameters are accessed by pressing “SET” after the name of the pa-rameter is displayed. The value of the parameter may be changed using the“UP” and “DOWN” buttons. After the desired value is reached press “SET” toset the parameter to the new value. Pressing “EXIT” will cause the parameter tobe skipped ignoring any changes that may have been made.

37

8 Controller operationController configuration

8.10.1 R0This probe parameter refers to the resistance of the control probe at 0°C. Nor-mally this is set for 100.000 ohms.

8.10.2 ALPHAThis probe parameter refers to the average sensitivity of the probe between 0and 100°C. Normally this is set for 0.00385°C-1.

8.11 Operating parametersThe operating parameters menu is indicated by,

PAr Operating parameters menu

Press “SET” to enter the menu. The operating parameters menu contains thecut-out reset mode parameter.

8.11.1 Cut-out reset modeThe cut-out reset mode determines whether the cut-out resets automaticallywhen the bath temperature drops to a safe value or must be manually reset bythe operator.

The parameter is indicated by,

CtorSt Cut-out reset mode parameter

Press “SET” to access the parameter setting. Normally the cut-out is set formanual mode.

Cto=rst Cut-out set for manual reset

To change to automatic reset mode press “UP” and then “SET”.

Cto=Auto Cut-out set for automatic reset

8.11.2 Stir mode selectThis parameter along with the Stirrer Set-point allows the user to set the tem-perature at which the stirrer motor is activated. This setting is generally usedwhen salt is used for the bath medium. For example, you can set the mode to“auto” and the temperature to 200°C. This allows the stirrer motor to shut offand turn on only when the salt is a liquid (>200°C) preventing the stirrer motorfrom overheating and damage.

The parameter is indicated by,


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38

Str Act Stirrer mode selection parameter

Press “SET” to access the parameter setting.

Str=Auto Stirrer is set for automatic activation at the stirrer set-pointtemperature.

To change the setting to always on press the “UP” or “DOWN” buttons andthen “SET”. When set to “Str=On” the stirrer motor comes on with the bathpower regardless of the temperature set in the stirrer set-point parameter.

8.11.3 Stir set-pointAllows setting of the temperature above which the stirrer motor will activatewhen the stirrer activation is set to automatic.

To access the paramter press “SET” from the stirrer activation parameter.Set-point mode selection parameter is indicated by,

Str SEt Stirrer motor activation set-point parameter

Press “SET” to access the parameter value.

Str=200 Stirrer motor activation set-point

Press “UP” or “DOWN” to change the value and then “SET” to enter the newvalue.

NOTE: Stir Mode Select defaults to “ ” each time the power of thebath is cycled off and back on. Therefore, this parameter has to be seteach time the bath is powered on if “ ” is the desired mode of op-eration.

8.11.4 Heat up power

NOTE: This section applies to controller parameters, not to the High/Lowsetting of the front panel heater switch.

This feature helps lengthen the lifetime of the heaters when using heat transfersalt as the bath fluid. The heater power will be limited to less than 30% whilethe salt is solid at low temperatures to prevent the heaters from overheating.Once the temperature reaches 200°C the heaters can then operate at 100%power.

HEAt UP Heat up power option

Press “SET” to access the parameter value.

39

8 Controller operationOperating parameters

HU=LO Low power heat up mode for heat transfer salt

HU=HI High power heat up mode

Press “UP” or “DOWN” to change the option and then press “SET” to store thesetting.

NOTE: When using salt as the fluid be sure to always set this option toLO to maximize the lifetime of the heaters.

8.12 Serial interface parametersThe optional serial RS-232 interface parameters menu is indicated by,

SErIAL Serial RS-232 interface parameters menu

The serial interface parameters menu contains parameters which determine theoperation of the serial interface. These controls only apply to baths fitted withthe serial interface. The parameters in the menu are — baud rate, sample pe-riod, duplex mode, and linefeed.

8.12.1 Baud rateThe baud rate is the first parameter in the menu. The baud rate setting deter-mines the serial communications transmission rate.

The baud rate parameter is indicated by,

BAUd Serial baud rate parameter

Press “SET” to choose to set the baud rate. The current baud rate value willthen be displayed.

1200 b Current baud rate

The baud rate of the bath serial communications may be programmed to300,600,1200, or 2400 baud. Use “UP” or “DOWN” to change the baud ratevalue.

2400 b New baud rate

Press “SET” to set the baud rate to the new value or “EXIT” to abort the opera-tion and skip to the next parameter in the menu.


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8.12.2 Sample periodThe sample period is the next parameter in the serial interface parameter menu.The sample period is the time period in seconds between temperature measure-ments transmitted from the serial interface. If the sample rate is set to 5, for in-stance, the bath transmits the current measurement over the serial interfaceapproximately every five seconds. The automatic sampling is disabled with asample period of 0. The sample period is indicated by,

SAmPLE Serial sample period parameter

Press “SET” to choose to set the sample period. The current sample periodvalue will be displayed.

SA= 1 Current sample period (seconds)

Adjust the value with “UP” or “DOWN” and then use “SET” to set the samplerate to the displayed value.

SA= 60 New sample period

8.12.3 Duplex modeThe next parameter is the duplex mode. The duplex mode may be set to full du-plex or half duplex. With full duplex any commands received by the bath viathe serial interface will be immediately echoed or transmitted back to the de-vice of origin. With half duplex the commands will be executed but not echoed.The duplex mode parameter is indicated by,

dUPL Serial duplex mode parameter

Press “SET” to access the mode setting.

dUP=FULL Current duplex mode setting

The mode may be changed using “UP” or “DOWN” and pressing “SET”.

dUP=HALF New duplex mode setting

8.12.4 LinefeedThe final parameter in the serial interface menu is the linefeed mode. This pa-rameter enables (on) or disables (off) transmission of a linefeed character (LF,ASCII 10) after transmission of any carriage-return. The linefeed parameter isindicated by,

LF Serial linefeed parameter

41

8 Controller operationSerial interface parameters

Press “SET” to access the linefeed parameter.

LF= On Current linefeed setting

The mode may be changed using “UP” or “DOWN” and pressing “SET”.

LF= OFF New linefeed setting

8.13 IEEE-488 parametersBaths may optionally be fitted with an IEEE-488 GPIB interface. In this casethe user may set the interface address within the IEEE-488 parameter menu.This menu does not appear on baths not fitted with the interface. The menu isindicated by,

IEEE IEEE-488 parameters menu

Press “SET” to enter the menu.

8.13.1 IEEE-488 addressThe IEEE-488 interface must be configured to use the same address as the ex-ternal communicating device. The address is indicated by,

AddrESS IEEE-488 interface address

Press “SET” to access the address setting.

Add= 22 Current IEEE-488 interface address

Adjust the value with “UP” or “DOWN” and then use “SET” to set the addressto the displayed value.

Add= 15 New IEEE-488 interface address

8.14 Calibration parametersThe operator of the bath controller has access to a number of the bath calibra-tion constants, namely CTO, C0, CG, H, and L. These values are set at the fac-tory and must not be altered. The correct values are important to the accuracyand proper and safe operation of the bath. Access to these parameters is avail-able to the user only so that in the event that the controller’s memory fails theuser may restore these values to the factory settings. The user should have a listof these constants and their settings with the manual.


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CAUTION: DO NOT change the values of the bath calibration constantsfrom the factory set values. The correct setting of these parameters is im-portant to the safety and proper operation of the bath.

The calibration parameters menu is indicated by,

CAL Calibration parameters menu

Press “SET” five times to enter the menu.

8.14.1 CTOParameter CTO sets the calibration of the over-temperature cut-out. This is notadjustable by software but is adjusted with an internal potentiometer. For the6055 bath this parameter should read between 560 and 570.

8.14.2 CO and CGThese parameters calibrate the accuracy of the bath set-point. These are pro-grammed at the factory when the bath is calibrated. Do not alter the value ofthese parameters. If the user desires to calibrate the bath for improved accuracythen calibrate R0 and ALPHA according to the procedure given in Section 10.

8.14.3 H and LThese parameters set the upper and lower set-point limits of the bath. DO NOTchange the values of these parameters from the factory set values. To do so maypresent danger of the bath overheating and causing damage or fire.

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8 Controller operationCalibration parameters

9 Digital communication interface

If supplied with the option, the 6055 bath is capable of communicating withand being controlled by other equipment through the digital interface. Twotypes of digital interface are available — the RS-232 serial interface and theIEEE-488 GPIB interface.

9.1 Serial communicationsThe bath may be installed with an RS-232 serial interface that allows serial dig-ital communications over fairly long distances. With the serial interface the usermay access any of the functions, parameters and settings discussed in Section7with the exception of the BAUD rate setting. The serial interface operates with8 data bits, 1 stop bit, and no parity. The use of a shielded communications ca-ble is recommended.

9.1.1 WiringThe serial communications cable attaches to the bath through the DB-9 connec-tor on the back panel. Figure 8 shows the pin-out of this connector and sug-gested cable wiring. Toeliminate noise, the serial ca-ble should be shielded withlow resistance between theconnector (DB-9) and theshield.

9.1.2 SetupBefore operation, the serialinterface of the bath must firstbe set up by programming theBAUD rate and other configu-ration parameters. These pa-rameters are programmedwithin the serial interfacemenu. The serial interface pa-rameters menu is outlined inFigure 6.

To enter the serial parameterprogramming mode first press“EXIT” while pressing “SET”and release to enter the sec-ondary menu. Press “SET” re-peatedly until the displayreads “ProbE”. This is themenu selection. Press “UP”

45

9 Digital communication interfaceSerial communications

Figure 8 Serial Cable Wiring Diagram

repeatedly until the serial interface menu is indicated with “SErIAL”. Finallypress “SET” to enter the serial interface parameters menu. In the serial interfaceparameters menu are the baud rate, sample rate, duplex mode, and linefeedparameters.

9.1.2.1 Baud rate

The baud rate is the first parameter in the menu. The display will prompt withthe baud rate parameter by showing “BAUd”. Press “SET” to choose to set thebaud rate. The current baud rate value will then be displayed. The baud rate ofthe serial communications may be programmed to 300, 600, 1200, or 2400baud. The baud rate is pre-programmed to 1200 baud. Use “UP” or “DOWN”to change the baud rate value. Press “SET” to set the baud rate to the new valueor “EXIT” to abort the operation and skip to the next parameter in the menu.

9.1.2.2 Sample period

The sample period is the next parameter in the menu and prompted with “SAm-PLE”. The sample period is the time period in seconds between temperaturemeasurements transmitted from the serial interface. If the sample rate is set to5, for instance, the bath transmits the current measurement over the serial inter-face approximately every five seconds. The automatic sampling is disabled witha sample period of 0. Press “SET” to choose to set the sample period. Adjustthe period with “UP” or “DOWN” and then use “SET” to set the sample rate tothe displayed value.

9.1.2.3 Duplex mode

The next parameter is the duplex mode indicated with “dUPL”. The duplexmode may be set to half duplex (“HALF”) or full duplex (“FULL”). With fullduplex any commands received by the bath via the serial interface will be im-mediately echoed or transmitted back to the device of origin. With half duplexthe commands will be executed but not echoed. The default setting is full du-plex. The mode may be changed using “UP” or “DOWN” and pressing “SET”.

9.1.2.4 Linefeed

The final parameter in the serial interface menu is the linefeed mode. This pa-rameter enables (“On”) or disables (“OFF”) transmission of a linefeed charac-ter (LF, ASCII 10) after transmission of any carriage-return. The default settingis with linefeed on. The mode may be changed using “UP” or “DOWN” andpressing “SET”.

9.1.3 Serial operationOnce the cable has been attached and the interface set up properly the control-ler will immediately begin transmitting temperature readings at the pro-grammed rate. The serial interface operates with 8 data bits, 1 stop bit, and noparity. The set-point and other commands may be sent to the bath via the serialinterface to set the bath and view or program the various parameters. The inter-


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face commands are discussed in Section 9.3. All commands are ASCII charac-ter strings terminated with a carriage-return character (CR, ASCII 13).

9.2 IEEE-488 communication (optional)The IEEE-488 interface is available as an option. Baths supplied with this op-tion may be connected to a GPIB type communication bus which allows manyinstruments to be connected and controlled simultaneously. To eliminate noise,the GPIB cable should be shielded.

9.2.1 Setup and address selectionTo use the IEEE-488 interface first connect an IEEE-488 standard cable to theback of the bath.

Next set the device address. This parameter is programmed within theIEEE-488 interface menu. To enter the IEEE-488 parameter programmingmenu first press “EXIT” while pressing “SET” and release to enter the second-ary menu. Press “SET” repeatedly until the display reaches “PrObE”. This isthe menu selection. Press “UP” repeatedly until the IEEE-488 interface menu isindicated with “IEEE”. Press “SET” to enter the IEEE-488 parameter menu.The IEEE-488 menu contains the IEEE-488 address parameter.

The IEEE-488 address is prompted with “AddrESS”. Press “SET” to programthe address. The default address is 22. Change the device address of the bath ifnecessary to match the address used by the communication equipment bypressing “UP” or “DOWN” and then “SET”.

9.2.2 IEEE-488 operationCommands may now be sent via the IEEE-488 interface to read or set the tem-perature or access other controller functions. All commands are ASCII charac-ter strings and are terminated with a carriage-return (CR, ASCII 13). Interfacecommands are listed below.

9.3 Interface commandsThe various commands for accessing the bath controller functions via the digi-tal interfaces are listed in this section (see Table 1). These commands are usedwith both the RS-232 serial interface and the IEEE-488 GPIB interface. In ei-ther case the commands are terminated with a carriage-return character. The in-terface makes no distinction between upper and lower case letters, hence eithermay be used. Commands may be abbreviated to the minimum number of letterswhich determines a unique command. A command may be used to either set aparameter or display a parameter depending on whether or not a value is sentwith the command following a “=” character. For example “s”<CR> will returnthe current set-point and “s=50.00”<CR> will set the set-point (set-point 1) to50.00 degrees.

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9 Digital communication interfaceIEEE-488 communication (optional)


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48

Command DescriptionCommandFormat

CommandExample Returned

ReturnedExample

AcceptableValues

Display Temperature

Read current set-point s[etpoint] s set: 9999.99 {C or F} set: 150.00 C

Set current set-point to n s[etpoint]=n s=450 InstrumentRange

Read vernier v[ernier] v v: 9.99999 v: 0.00000

Set vernier to n v[ernier]=n v=.00001 Depends onConfiguration

Read temperature t[emperature] t t: 9999.99 {C or F} t: 55.69 C

Read temperature units u[nits] u u: x u: c

Set temperature units: u[nits]=c/f C or F

Set temperature units to Celsius u[nits]=c u=c

Set temperature units toFahrenheit

u[nits]=f u=f

Secondary Menu

Read proportional band setting pr[op-band] pr pb: 999.9 pb: 15.9

Set proportional band to n pr[op-band]=n pr=8.83 Depends onConfiguration

Read cut-out setting c[utout] c c: 9999 {x},{xxx} c: 620 C, in

Set cut-out setting: c[utout]=n/r[eset]

Set cut-out to n degrees c[utout]=n c=500 TemperatureRange

Reset cut-out now c[utout]=r[eset] c=r

Read heater power(duty cycle)

po[wer] po po: 9999 po: 1

Configuration Menu

Probe Menu

Read R0 calibration parameter r[0] r r0: 999.999 r0: 100.578

Set R0 calibration parameter to n r[0]=n r=100.324 98.0 to 104.9

Read ALPHA calibrationparameter

al[pha] al al: 9.9999999 al: 0.0038573

Set ALPHA calibration parameterto n

al[pha]=n al=0.0038433 .00370 to.00399

Operating Parameters Menu

Read cut-out mode cm[ode] cm cm: {xxxx} cm: AUTO

Set cut-out mode: cm[ode]=r[eset]/a[uto] RESET orAUTO

Set cut-out to be reset manually- cm[ode]=r[eset] cm=r

Table 1 Interface command summary

49

9 Digital communication interfaceInterface commands



ReturnedExample

AcceptableValues

Set cut-out to be resetautomatically

cm[ode]=a[uto] cm=a

Read Stirrer Mode smod smod smod: {xxxx} smod: AUTO

Set Stirrer Mode: smod=o/a ON or AUTO

Set stirrer activationmode to on

smod=o smod=o

Set stirrer activationmode to auto

smod=a smode=a

Read Stirrer Set-Point sset sset sset: 9999.99 {C or F} sset: 160.00C

Set Stirrer Set-Point to n sset=n sset=160 instrumentrange

Serial Interface Menu

Read serial sample setting sa[mple] sa sa: 9 sa: 1

Set serial sampling setting to nseconds

sa[mple]=n sa=0 0 to 4000

Set serial duplex mode: du[plex]=f[ull]/h[alf] FULL or HALF

Set serial duplex mode to full du[plex]=f[ull] du=f

Set serial duplex mode to half du[plex]=h[alf] du=h

Set serial linefeed mode: lf[eed]=on/of[f] ON or OFF

Set serial linefeed mode to on lf[eed]=on lf=on

Set serial linefeed mode to off lf[eed]=of[f] lf=of

Calibration Menu

Read C0 calibration parameter *c0 *c0 c0: 9 c0: 0

Set C0 calibration parameter to n *c0=n *c0=0 –999.9 to 999.9

Read CG calibration parameter *cg *cg cg: 999.99 cg: 406.25

Set CG calibration parameter to n *cg=n *cg=406.25 –999.9 to 999.9

Read low set-point limit value *tl[ow] *tl tl: 999 tl: –80

Set low set-point limit to n *tl[ow]=n *tl=-80 –999.9 to 999.9

Read high set-point limit value *th[igh] *th th: 999 th: 205

Set high set-point limit to n *th[igh]=n *th=205 –999.9 to 999.9

Miscellaneous (not on menus)

Read firmware version number *ver[sion] *ver ver.9999,9.99 ver.2100,3.56

Read structure of all commands h[elp] h list of commands

Read Heater 1 f1 f1 f1:9 f1:1

Set Heater 1 f1=1/0 1 or 0

Interface command summary cont.


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ReturnedExample

AcceptableValues

Set heater 1 to on f1=n f1=1

Set heater 1 to off f1=n f1=0



Set Heater 2 to on f2=n f2=1

Set Heater 2 to off f2=n f2=0









Read Boost Heater f5 f5 f5:9 f5:1

Set Boost Heater f5=1/0 1 or 0

Set Boost Heater to on f5=n f5=1

Set Boost Heater to off f5=n f5=0

Legend: [] Optional Command data

{} Returns either information

n Numeric data supplied by user

9 Numeric data returned to user

x Character data returned to user

Note: When DUPLEX is set to FULL and a command is sent to READ, the command is returned followed by acarriage return and linefeed. Then the value is returned as indicated in the RETURNED column.

Interface command summary cont.

In Table 1, characters or data within brackets, “[” and “]”, are optional for thecommand. A slash, “/”, denotes alternate characters or data. Numeric data, de-noted by “n”, may be entered in decimal or exponential notation. Characters areshown in lower case although upper case may be used. Spaces may be addedwithin command strings and will simply be ignored. Backspace (BS, ASCII 8)may be used to erase the previous character. A terminating CR is implied withall commands.

9.4 Power commandsThe digital interface is capable of controlling the heating functions so that thebath can be remotely operated at any temperature within the range of the bath.To allow the interface to control the heating, the front panel controls are dis-abled by 1) switching the heater control to “OFF”, and 2) switching the boostheater switch to “OFF”. Otherwise, the interface would not be able to switchthese functions off. The 6055 bath has five control functions with the digital in-terface. These are controls for heaters 1, 2, 3, and 4, each 225 W, and the boostheater which is 900 W. Heater 1 power could be varied with the DRIFT controlon the front panel. The boost heater should only be used for quickly heating thebath up to a high temperature and not for controlling at a constant temperature.

Serial commands “F1” through “F5” control the heaters 1 through 4 and theboost heater individually. These commands are used to turn the heaters on oroff or to read the states of the heaters. Sending a command with parameter “1”turns the heater on. Parameter “0” turns the heater off. No parameter returns thestate, “1” for on or “0” for off. For example “F1=1”<RETURN> turns onheater 1. “F1”<RETURN> (no parameter) will return “f1:1” or “f1:0” depend-ing on whether heater 1 is on or off respectively.

Since unlike the front panel heater control, which turns on multiple heaters toachieve the desired power level, the interface commands control the heaters in-dividually, multiple commands must be issued to set the desired amount ofpower. Table 2 lists the commands which should be given to set various power

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9 Digital communication interfacePower commands

levels. Power is variable with the front panel DRIFT control when heater 1 (F1)is turned on.

9.5 Heater settings for controlSuggested heater control settings for various ranges are suggested below.

Range Controls

150°C–250°C LOW - Heater 1 on, heaters 2–4 and boost heater off

250°C–350°C MEDIUM - Heaters 1 and 2 on, heater 3, 4, and boost heater off

350°C–450°C MEDIUM HIGH - Heaters 1–3 on and heater 4 and boost heater off

450°C–550°C HIGH - Heaters 1–4 and boost heater on


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POWER F1 F2 F3 F4 F5

OFF 0 0 0 0 0

0–225 W LOW 1 0 0 0 0

225–450 WMEDIUM

1 1 0 0 0

450–675 WMEDIUM HIGH

1 1 1 0 0

675–900 W HIGH 1 1 1 1 0

1800 W BOOST 1 1 1 1 1

Table 2 Power Commands

10 Calibration procedure

In some instances the user may want to calibrate the bath to improve the tem-perature set-point accuracy. Calibration is done by adjusting the controllerprobe calibration constants R0 and ALPHA so that the temperature of the bathas measured with a standard thermometer agrees more closely with the bathset-point. The thermometer used must be able to measure the bath fluid temper-ature with higher accuracy than the desired accuracy of the bath. By using agood thermometer and carefully following procedure the bath can be calibratedto an accuracy of better than 0.02°C over a range of 100 degrees.

10.1 Calibration pointsIn calibrating the bath R0 and ALPHA are adjusted to minimize the set-pointerror at each of two different bath temperatures. Any two reasonably separatedbath temperatures may be used for the calibration however best results will beobtained when using bath temperatures which are just within the most usefuloperating range of the bath. The further apart the calibration temperatures thelarger will be the calibrated temperature range but the calibration error will alsobe greater over the range. If for instance 50°C and 150°C are chosen as the cali-bration temperatures then the bath may achieve an accuracy of say ±0.03°Cover the range 40 to 160°C. Choosing 80°C and 120°C may allow the bath tohave a better accuracy of maybe ±0.01°C over the range 75 to 125°C but out-side that range the accuracy may be only ±0.05°C.

10.2 Measuring the set-point errorThe first step in the calibration procedure is to measure the temperature errors(including sign) at the two calibration temperatures. First set the bath to thelower set-point which we will call tL. Wait for the bath to reach the set-pointand allow 15 minutes to stabilize at that temperature. Check the bath stabilitywith the thermometer. When both the bath and the thermometer have stabilizedmeasure the bath temperature with the thermometer and compute the tempera-ture error errL which is the actual bath temperature minus the set-point temper-ature. If for example the bath is set for a lower set-point of tL=50°C and thebath reaches a measured temperature of 49.7°C then the error is -0.3°C.

Next, set the bath for the upper set-point tH and after stabilizing measure thebath temperature and compute the error errH. For our example we will supposethe bath was set for 150°C and the thermometer measured 150.1°C giving anerror of +0.1°C.

10.3 Computing R0 and ALPHABefore computing the new values for R0 and ALPHA the current values mustbe known. The values may be found by either accessing the probe calibration

53

10 Calibration procedureCalibration points

menu from the controller panel or by inquiring through the digital interface.The user should keep a record of these values in case they may need to be re-stored in the future. The new values R0′ and ALPHA′ are computed by enteringthe old values for R0 and ALPHA, the calibration temperature set-points tL andtH, and the temperature errors errL and errH into the following equations,

Rerr t err t

t tALPHA RH L L H

H L

0 1 0′ = −−

+⎡

⎣⎢

⎤

⎦⎥

ALPHAALPHA t err ALPHA t err

t tH L L H

H L

′ = + − +−

+⎡

⎣⎢

⎤

⎦

( ) ( )1 11⎥ ALPHA

If for example R0 and ALPHA were previously set for 100.000 and 0.0038500respectively and the data for tL, tH, errL, and errH were as given above then thenew values R0′ and ALPHA′ would be computed as 100.193 and 0.0038272 re-spectively. Program the new values R0 and ALPHA into the controller. Checkthe calibration by setting the temperature to tL and tH and measuring the errorsagain. If desired the calibration procedure may be repeated again to further im-prove the accuracy.

10.4 Calibration exampleThe bath is to be used between 75 and 125°C and it is desired to calibrate thebath as accurately as possible for operation within this range. The current val-ues for R0 and ALPHA are 100.000 and 0.0038500 respectively. The calibra-tion points are chosen to be 80.00 and 120.00°C. The measured bathtemperatures are 79.843 and 119.914°C respectively. Refer to Figure 9 for ap-plying equations to the example data and computing the new probe constants.


User’s Guide

54

55

10 Calibration procedureCalibration example

R0 = 100.000

ALPHA = 0.0038500

tL = 80.00°C

measured t = 79.843°C

tH = 120.00°C

measured t = 119.914°C

Compute errors,

errL = 79.843 - 80.00°C = -0.157°C

errH = 119.914 - 120.00°C = -0.086°C

Compute R0,

R0

0 086 80 0 0157 120 0

120 0 80 00 00385′ = − − −

−+( . ) . ( . ) .

. ..

x x1 100 000 100115

⎡

⎣⎢

⎤

⎦⎥ =. .

Compute ALPHA,

ALPHA′ = + − − +( . . )( . ) ( . . )(1 0 00385 120 0 0157 1 0 00385 80 0x x −−

+⎡

⎣⎢

⎤

⎦⎥ =0 086

120 0 80 01 0 00385 0 0038387

. )

. .. .

Figure 9 Calibration example

11 Maintenance

The calibration instrument has been designed with the utmost care. Ease of op-eration and simplicity of maintenance have been a central theme in the productdevelopment. Therefore, with proper care the instrument should require verylittle maintenance. Avoid operating the instrument in dirty or dustyenvironments.

• A battery is used to maintain operating parameters in the unit. All operat-ing parameters, including calibration parameters should be checked on aregular basis to insure accuracy and proper operation of the instrument.See the troubleshooting section for the procedure on checking the statusof the battery.

• The bath should be cleaned regularly to prevent a buildup of salt. Use apaint safe cleaning agent on all painted surfaces. Solvents such as Trichlo-roethylene or Acetone may dull or dissolve the paint. The stainless steelsurfaces may be cleaned with solvents as necessary to remove oils.

• The stirring motor should be clean to allow proper cooling. Normallyonly the outside surfaces require any attention. If the inside of the motorhas become heavily loaded with salt, blow it out with compressed air. Fol-low normal safety procedures when using pressurized gasses.

• Salt expands and contracts with temperature. Be sure that the correctamount of salt is used for the temperature. If the bath is used at a lowertemperature and then raised to a higher temperature, some of the moltensalt may need to be carefully removed to prevent overflow.

• Periodically check the fluid level in the bath to ensure that the level hasnot dropped. A drop in the fluid level affects the stability of the bath.Changes in fluid level are dependent upon several factors specific to theenvironment in which the equipment is used. A schedule cannot be out-lined to meet each environmental setting. Therefore, the first year the bathshould be checked weekly with notes kept as to changes in bath fluid. Af-ter the first year, the user can set up a maintenance schedule based on thedata specific to the application.

• Salt requires little maintenance. There is very little evaporation with salt.Periodic fluid level checks are usually sufficient.

• If a hazardous material is spilt on or inside the equipment, the user is re-sponsible for taking the appropriate decontamination steps as outlined bythe national safety council with respect to the material. MSDS sheets ap-plicable to all fluids used in the baths should be kept in close proximity tothe instrument.

• If the mains supply cord becomes damaged, replace it with a cord withthe appropriate gauge wire for the current of the bath. If there are anyquestions, contact an Authorized Service Center for more information.

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11 Maintenance

• Before using any cleaning or decontamination method except those rec-ommended by Hart, users should check with an Authorized Service Cen-ter to be sure that the proposed method will not damage the equipment.

• If the instrument is used in a manner not in accordance with the equip-ment design, the operation of the bath may be impaired or safety hazardsmay arise.

• The over-temperature cut-out should be checked every 6 months to seethat it is working properly. In order to check the user selected cut-out, fol-low the controller directions (Section 8.2) for setting the cut-out. Both themanual and the auto reset option of the cut-out should be checked. Set thebath temperature higher than the cut-out. Check to see if the displayflashes cut-out and the temperature is decreasing.

WARNING: When checking the over-temperature cut-out, be sure that thetemperature limits of the bath fluid are not exceeded. Exceeding the tem-perature limits of the bath fluid could cause harm to the operator, lab, andinstrument.

• The constant temperature bath depends upon the certain qualities of thefluid medium in order to maintain a uniform and stable temperature envi-ronment.


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12 Troubleshooting

In the event the bath appears to function abnormally this section may help tofind and solve the problem. Several possible problem conditions are describedalong with likely causes and solutions. If a problem arises please read this sec-tion carefully and attempt to understand and solve the problem. If the bathseems faulty or the problem cannot otherwise be solved, then contact an Autho-rized Service Center for assistance. Opening the unit without contacting an Au-thorized Service Center may void the warranty.

12.1 Troubleshooting

Problem Causes and Solutions

The heater indicator LEDstays red but the temper-ature does not increase

If the display does not show “cutout” and shows the correct bath temperature,consider the following possibilities:Insufficient heating. Insufficient heating may be caused by the heater power

setting being too low, especially at higher operating temperatures. Switching tothe higher heater power switch setting, if available, may solve the problem.No heating. This is caused by blown heater fuses and/or burned out heaters.Check the heater fuses to make sure that they are still good. Access the heaterfuses by removing the L-shaped panel covering the display electronics. If theyare blown, and continue to blow when replaced, the heaters may be shorted. Ifyou suspect that the heaters are shorted or burned out, contact an AuthorizedService Center (see Section 1.3) for assistance.

The controller displayflashes “CUToUT” andthe heater does notoperate

If the display flashes “CUToUT” alternately with the correct process tempera-ture, check the following:Wrong cutout setting. The cutout disconnects power to the heaters when thebath temperature exceeds the cutout set-point. This causes the bath tempera-ture to drop back down to a safe value. If the cutout mode is set to “AUTO”, theheater switches back on when the temperature drops. If the mode is set to “RE-SET”, the heater only comes on again when the temperature is reduced and theoperator manually resets the cutout. (Refer to Section 8.11.1.)Check that the cutout set-point is adjusted to 10 or 20°C above the desiredmaximum bath operating temperature and that the cutout mode is set asdesired.Continuous cutout. If the cutout activates when the bath temperature is well be-low the cutout set-point or the cutout does not reset when the bath temperaturedrops and it is manually reset, the cutout circuitry may be faulty. Try performingthe Factory Reset Sequence explained below.Factory Reset Sequence - Hold the “SET” and “EXIT” keys down at the sametime while powering up the unit. The display shows “-init”, the model number,and the firmware version. Each of the controller parameters and calibration con-stants must be re-programmed. The values can be found on the Report of Cali-bration that was shipped with the instrument.

59

12 TroubleshootingTroubleshooting


The display flashes“CUToUT” alternatelywith an incorrect processtemperature

Low battery. A problem could exist with the memory back-up battery. If the bat-tery voltage is insufficient to maintain the memory, data may become scrambledcausing problems. A nearby large static discharge may also affect data in mem-ory. Access the battery by removing the L-shaped panel covering the displayelectronics.Corrupt controller memory. If the problem reoccurs after the battery is replaced,initialize the memory by performing a Factory Reset Sequence (described in aprevious solution).

The controller displaysthe wrong temperatureand the bath continuallyheats or cools regardlessof the set-point value

Defective control probe. The bath control probe may be disconnected, burnedout, or shorted. Check first that the probe is connected properly to the socket inthe rear of the bath labeled “PROBE”.The probe may be checked with an ohmmeter to see if it is open or shorted.The probe is a platinum 4-wire Din 43760 type. The resistance should read 0.2to 2.0 ohms between pins 1 and 2 on the probe connector and 0.2 to 2.0 ohmsbetween pins 3 and 4. The resistance should read from 100 to 300 ohms be-tween pins 1 and 4 depending on its current temperature.Corrupt controller memory. Initialize the memory by performing a Factory ResetSequence (described in a previous solution).

The controller controls orattempts to control at aninaccurate temperature

If the controller appears to operate normally except that the bath’s temperaturedoes not agree with the temperature measured by the user’s reference ther-mometer to within the specified accuracy, consider the following:Erroneous parameters. Check that the calibration parameters are all correct ac-cording to the Report of Calibration. If not, reprogram the constants. If the con-troller does not keep the correct parameters, the memory backup battery maybe weak causing errors in data. See “Low Battery” in a previous solution.Poor uniformity. There may be an actual difference between the bath’s controlprobe and the reference thermometer due to excess gradients in the bath.Check that the bath has an adequate amount of fluid in the tank and that thestirrer is operating properly. Also check that the reference thermometer andcontrol probe are both fully inserted into the bath to minimize temperature gradi-ent errors.Defective control probe. Check that the control probe has not been struck, bent,or damaged. Refer to the previous solution for how to check the probe’sresistance.

The controller shows thatit is controlling at theproper temperature, butthe bath temperature isunstable

If the bath does not achieve the expected degree of temperature stability whenmeasured using a thermometer, consider the following:Wrong proportional band setting. If the proportional band is set too narrow, thebath will oscillate causing poor stability. In this case, increase the width of theproportional band.If the proportional band setting is too wide, the long-term stability of the bath isaffected. In this case decrease the width of the band. (Refer to Section 8.7.)Bath salt is too thick. Make sure that the bath salt used is less than 50centistokes (10 is ideal) at the temperature at which the bath is controlling.Check the salt manufacturer’s specifications.Defective control probe. Check that the control probe has not been struck, bent,or damaged. Refer to the previous solution for how to check the probe’sresistance.

The controller alternatelyheats for a while thencools

Wrong proportional band setting. If the proportional band is set too narrow, thebath will oscillate between too much heating and too much cooling causing in-stability. Increase the width of the proportional band until the temperature stabi-lizes. (Refer to Section 8.7.)


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60


Stir motor does notfunction

Improper setting or normal operation. See Section 8.11.2, Stir Mode Select, forproper stir mode settings.

Note: Stir Mode Select defaults to “Auto” each time the power of thebath is cycled off and back on. Therefore, this parameter has to be set eachtime the bath is powered on if “Str-ON” is the desired mode of operation.If stir motor still does not function, contact an Authorized Service Center forassistance .

The controller does notmaintain controller pa-rameters or parametersare reset each time thepower to the unit isremoved

Note: Before performing the memory check,you need to record the controllercalibration parameters (found in the CAL menu of the instrument) and anyuser-adjusted parameters that you have changed (such as the programmableset points and proportional band).Memory CheckDoing a memory check is the easiest way to verify the ability of the battery tomaintain controller parameters.1. Power off the instrument.2. Disconnect the instrument from AC power for 10 seconds.3. Reconnect the AC power and power on the instrument.4. If the display shows InIT and/or the cycle count shows a low number such as0002, the battery is spent and should be replaced. Contact a Hart Scientific Au-thorized Service Center for assistance.5. After replacing the battery, you must reprogram the calibration and user-ad-justable parameters into the controller.

12.2 Comments

12.2.1 EMC DirectiveHart Scientific’s equipment has been tested to meet the European Electromag-netic Compatibility Directive (EMC Directive, 89/336/EEC). The Declarationof Conformity for your instrument lists the specific standards to which the unitwas tested.

12.2.2 Low Voltage Directive (Safety)In order to comply with the European Low Voltage Directive (73/23/EEC),Hart Scientific equipment has been designed to meet the IEC 1010-1 (EN61010-1) and the IEC 1010-2-010 (EN 61010-2-010) standards.

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12 TroubleshootingComments

calibration bath user’s guide

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