calibration bathdownload.flukecal.com/pub/literature/6054___rgeng0000.pdf · 2016-03-17 · 1...

6054Calibration Bath

User Manual

October 2013© 2013 Fluke Corporation. All rights reserved. Specifications are subject to change without notice. All product names are trademarks of their respective companies.

WARNINGTo ensure the safety of operating personnel, and to avoid damage to this unit:

DO NOT operate this unit without a properly grounded, properly polarized power cord.DO NOT connect this unit to a non-grounded, non-polarized outlet.

DO use a ground fault interrupt device.

WARNINGHIGH TEMPERATURES PRESENT

in this equipment.

FIRES and SEVERE BURNSmay result if personnel fail to observe safety precautions.

WARNINGHIGH VOLTAGE

is used in the operation of this equipment.

SEVERE INJURY or DEATHmay result if personnel fail to observe safety precautions.

Before working inside the equipment, turn power off and disconnect power cord.

WARNING

Fluids used in this bath may produce

NOXIOUS OR TOXIC FUMESunder certain circumstances.

Consult the fluid manufacturer’s MSDS (Material Safety Data Sheet).

PROPER VENTILATION ANDSAFETY PRECAUTIONS MUST BE OBSERVED.

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TABLE OF CONTENTS

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3 Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 113.1 Two Modes of Temperature Control . . . . . . . . . . . . . . . . . . . . . . 11

3.1.1 The Temperature Control Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.1.2 The Temperature Drift Mode: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.1.3 The Fluid system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.2 Description Of Features and Controls . . . . . . . . . . . . . . . . . . . . . 123.2.1 The Controller Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123.2.2 The Power Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.2.3 The Rear Panel: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.1 Receiving and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.2 Installation Location Requirements . . . . . . . . . . . . . . . . . . . . . . 16

4.2.1 Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.2.2 Electrical Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.2.3 Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4.3 Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.3.1 Filling the Bath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4.3.1.1 Filling the Bath With Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174.3.2 Draining the Oil from the Bath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

5 Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . 185.1 Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

6 Controller Operation . . . . . . . . . . . . . . . . . . . . . . . . . 196.1 Bath temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196.2 Reset Cutout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196.3 Temperature Set-point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6.3.1 Programmable Set-points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196.3.2 Set-point Value. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216.3.3 Set-point vernier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

6.4 Temperature Scale Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216.5 Secondary Menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226.6 Heater Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226.7 Proportional Band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226.8 Cutout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

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6.9 Controller Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246.10 Probe Parameters Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6.10.1 R0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246.10.2 ALPHA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

6.11 Operating Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256.11.1 Cutout Reset Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256.11.2 Stirrer Mode Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256.11.3 Stirrer set-point. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

6.12 Serial Interface Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 256.12.1 BAUD Rate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266.12.2 Sample Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266.12.3 Duplex Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266.12.4 Linefeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

6.13 IEEE-488 Parameters Menu . . . . . . . . . . . . . . . . . . . . . . . . . . 266.13.1 IEEE-488 Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

6.14 Calibration Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276.14.1 CTO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276.14.2 CO and CG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276.14.3 H and L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

6.15 Operation Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

7 Digital Communication Interface . . . . . . . . . . . . . . . . . . . 287.1 Serial Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

7.1.1 Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287.1.2 Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

7.1.2.1 BAUD rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287.1.2.2 Sample Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287.1.2.3 Duplex Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297.1.2.4 Linefeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.1.3 Serial Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.2 IEEE-488 Communication (optional) . . . . . . . . . . . . . . . . . . . . . . 297.2.1 Setup and Address Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297.2.2 IEEE-488 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.3 Interface Commands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297.4 Power Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317.5 Heater Settings for Control. . . . . . . . . . . . . . . . . . . . . . . . . . . 32

8 Bath Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338.1 Calibration Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338.2 Measuring the Set-point Error . . . . . . . . . . . . . . . . . . . . . . . . . 348.3 Computing R0 and ALPHA . . . . . . . . . . . . . . . . . . . . . . . . . . 348.4 Calibration Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

9 Bath Heat Transfer Fluid . . . . . . . . . . . . . . . . . . . . . . . 35

vi

9.1 Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359.2 Viscosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359.3 Specific heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359.4 Thermal Conductivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359.5 Thermal Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359.6 Electrical Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359.7 Fluid lifetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369.8 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369.9 Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

9.9.1 Commonly used fluids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369.9.2 Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369.9.3 Ethylene Glycol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369.9.4 Mineral Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369.9.5 Silicone oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379.9.6 Heat Transfer Salt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

9.10 Fluid Characteristics Charts . . . . . . . . . . . . . . . . . . . . . . . . . . 399.10.1 Limitations and Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399.10.2 About the Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

10 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4110.1 The Heater Indicator LED Stays Red But The Temperature Does Not In-

crease. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4110.2 The Controller Display Flashes “CUT-OUT” And The Heater Does Not Oper-

ate. 4110.3 The Display Flashes “CUT-OUT” And An Incorrect Process Temperature. . . 4110.4 The Displayed Process Temperature Is In Error And The Controller Remains In

The Cooling Or Heating State At Any Set-point Value. . . . . . . . . . . . . . . . . 4210.5 The Controller Controls Or Attempts To Control At An Inaccurate Tempera-

ture. 4210.6 The Controller Shows That The Output Power Is Steady But The Process Temper-

ature Is Unstable.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4210.7 The Controller Alternately Heats For A While Then Cools. . . . . . . . . . . 4210.8 The Controller Erratically Heats Then Cools, Control Is Unstable. . . . . . . . 42

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1 Introduction

The Hart Scientific Model 6054 Calibration Bath is ahighly stable constant temperature liquid bath. It hasbeen designed for calibrating liquid and glass ther-mometers or other types of long thermometersagainst a known temperature standard such as aStandard Platinum Resistance Thermometer(SPRT).

The 6054 calibration bath provides the following fea-tures:

• A deep fluid tank (test well is 7.5 inches in di-ameter and has 24 inches of fluid depth).

• It provides a highly temperature stable low gra-dient environment typically a nominal stabilityof ±0.005°C with oils. The fluid is well stirred

and environmentally protected to minimizegradients.

• The fluid level is near the top of the test well tofacilitate calibration of liquid and glass ther-mometers without needing to compensate forstem effect.

• The bath provides two calibration modes. Anelectronically controlled mode uses a hybriddigital and analog PI controller with lock in am-plifier design.The temperature and other func-tions are selected with the four button keypadto a hundredth of a degree and finer with a digi-tal vernier adjustment. The Drift mode by-passes the controller with heater powermanually controlled with variable transformer.

Introduction

9

2 Specifications

Specifications

10

Power Required . . . . . . . . . 230 VAC; 60 Hz; 15 Amps max.

Bath Temperature Range . . . . 50°C to 325°C

Temperature Stability. . . . . . . ±0.005°C to 200°C, ±0.010°C to 325°C

Temperature Uniformity . . . . . ±0.005°C max

Controller Accuracy . . . . . . . ±0.5°C

Test Well Area . . . . . . . . . . 7.5-inches dia X 24-inches deep

Heater . . . . . . . . . . . . . . Electrical, 5 positions; 1=off, 2=250, 3=500, 4=750 & 5=1,000 watts at240 VAC line

Boost Heater . . . . . . . . . . . 750watts

Heat Transfer Liquid . . . . . . . Fluids compatible with stainless steel may be used. (e.g. oils such asDow Corning 710 and 210H or Hart Salt)

Exterior Dimensions . . . . . . . Height 56" X Width 31" X FB 23"

Weight . . . . . . . . . . . . . . 156 Lbs.

Table 1 Specifications

3 Theory of Operation

The components, features and operational theory ofthe Model 6054 calibration bath are described in thissection.

3.1 Two Modes ofTemperature Control

Two modes of temperature control are available withthe model 6054. The TEMPERATURE CONTROLmode or the TEMPERATURE DRIFT mode may beselected by a switch on the front panel.

3.1.1 The Temperature Control Mode

The control mode uses a hybrid digital/analog PI tem-perature controller with lock-in-amplifier. The bathstability is very high with this controller. The tempera-ture is selected using a four button keypad on the frontpanel. Temperatures from 0.00 to 325.00°C may beselected directly to a hundredth of a degree.Finer ad-justment is available using the vernier adjustment.Accuracy of the setting is typically ±0.5°C or better.

The controller pulses AC current to the control heat-ers in a time modulated fashion to compensate forheat gains and losses to the system. A two color LEDon the control panel glows red when the heaters areon and glows green when they are off and cooling istaking place. (Note: The cooling required for control issupplied through heat loss to ambient.)

The Temperature control probe uses a 100 ohm PRT.It is a totally separate unit for ease of replacement. It isinserted into the top of the bath near the stirring motoras shown and plugs into the rear of the control unit.

The heaters are external to the tank. They are ar-ranged electrically to provide the 4 control heating po-sitions plus an off position. The additional boostheating position is accessed from a separate switchon the control panel.

3.1.2 The Temperature Drift Mode:

In the Temperature Drift mode the heater may be setmanually to allow the temperature to drift very slowly

(a few milli-°C per minute) over the desired range.This allows the control noise to be eliminated al-though greater skill is required in making calibrations.The heater power is adjusted by means of a variabletransformer located on the control panel. It allows po-sition one of the heater selection switch to be continu-ally variable from 0 to 100% Positions 2, 3, 4 andBoost add their full value of heat incrementally to theadjusted value of position 1.

3.1.3 The Fluid system

The fluid system consists of the insulated tank, thestirrer assembly, the condensate drain, the overflowtest well, and the fluid itself. The heaters and probe,which are part of the control system, are physicallyexternal to the tank.

The tank and other wetted parts are made of stainlesssteel for compat ib i l i ty wi th most pract icalthermostating fluids.The stirrer is attached to the tanktop plate of the bath and its motor receives additionalcooling from a fan to keep from overheating and in-crease lifetime at high bath temperatures. The stirrerdirectly drives four 2-inch diameter stirring propellers.The down draft from the propellers forces the bathfluid through the overflow test well. The stirring motorplugs into the rear of the control unit. (See Figure 3 onpage 14.)

The over-flow test well serves to provide a constantdepth of fluid at an essentially constant height nearthe well opening. Variations in fluid volume due tothermal expansion and volatilization will not effectmeasurements within reasonable volume ranges.The fluid expelled from the tank is controlled to flowpast the control heaters first before entering the maintank for thermal management.

A drain is provided for convenience in changing thebath fluid. (See draining the tank.)

The condensate drain collects condensed oil vaporand oil that has expanded over the top of the tankwalls.Tubes on either side of the drain at the bottom ofthe bath allow the liquid to be collected into a pan. Besure this pan is in place at all times to prevent oil fromdraining onto the floor The condensate pan must be

Theory of Operation

11

EXIT — Used to exit from a menu. When EXIT ispressed any changes made to the displayed value willbe ignored.

3) The control indicator is a two color light emitting di-ode (LED).This indicator lets the user visually see theratio of heating to cooling. When the indicator is redthe heater is on, and when it is green the heater is offand the bath is cooling.

3.2.2 The Power Panel

The Power Panel (Figure 2) controls include; 1) TheMode Select switch and indicators, 2) the Drift Ad-just control 3) the control Heating select switch, 4)the Power switch and indicator, and 5) the BoostHeater and indicator.

1) The MODE SELECT switch selects between theTemperature Control and Drift Adjust modes. Lightsshow which mode is functioning. The TemperatureControl position selects the temperature controller tooperate and the desired temperature is selected onthe controller panel. In the Temperature Drift mode

heater control is via the Drift Adjust control and theHeating select switch.

2) The DRIFT ADJUST control is a variable trans-former that adjusts the Low control heater through 0to 100% of its power range. The additional power re-quired for higher temperatures may be added in stepsby selecting heating positions Medium, Medium High,and High, as required.

3) The control HEATING switch selects control heaterpower positions 1 through 5. Select the lowest rea-sonable value for normal control conditions depend-ing on bath temperature. The switch simply addsmore heaters into the circuit until the desired power isattained. Position 2 is variable using the Drift Adjustcontrol.

4) The POWER (On-Off) switch powers up the bath.The switch is a DPST type that opens both legs of the230 volt power source.A red indicator light shows thatpower is on.

5) The BOOST HEATING provides an additional 750watts for slewing between temperatures. The BoostHeating Indicator shows whether the boost heater ison or off. The boost heater is powered through the

Theory of Operation

13

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 AdjustControl1 2

34

5

Figure 2 Power panel

Theory of Operation

14

FUS

E FUS

E FUSE F

U

SE

1

2

3

4

5

6

7

8

Figure 3 Back panel

temperature controller triac to prevent exceeding thedesired set temperature. The boost heater indicatorwill flash when the set temperature has been reachedas a reminder to turn it off for control.

3.2.3 The Rear Panel:

The Rear Panel has many features (see Figure 3). 1)The PROBE connector, 8) STIRRER POWER outlet,7) FUSES, 6) Power Connection, 5) ELECTRONICSFUSE INTERNAL notation, 2) Unit SERIAL NO. no-tation, 3) optional SERIAL PORT and, 4) optionalIEEE-488 PORT.

1) The PROBE connector on the back panel is usedfor the temperature controller probe.

2) The unit SERIAL NO. is located at the top right cor-ner of the back panel. When consulting with the fac-tory, refer to the serial number.

3) SERIAL PORT (optional)

4) IEEE-488 PORT (optional)

5) The ELECTRONICS FUSE is located inside thecabinet and is a 1/4 amp fuse. To replace the elec-tronic fuse, remove the cover over the controller.

6) The POWER CORD connector

7) The SYSTEM FUSES are 15 amps slow blow (onefuse for each leg of the 230 VAC). The heater fusesare located internally and are 10 amp, 250 VAC.

8) The STIRRER POWER connection provides 230VAC to the stirring motor and its cooling fan.

Theory of Operation

15

4 Installation

The Model 6054 bath can be readily installed givendue care to the following instructions.

4.1 Receiving and Inspection

Upon receipt of the bath, inspect it to see that there isno obvious damage from shipment. If any damage isobserved, notify the carrier at once for an inspector tocheck out the damage.

Verify that all of the items ordered have been shipped.Notify Hart Scientific immediately if there are any dis-crepancies.

4.2 Installation LocationRequirements

4.2.1 Environment

The model 6054 bath is a precision instrument thatmust be located in an appropriate environment. Thelocation should be free from drafts, extreme tempera-tures and temperature changes, dirt, etc. The bathmust be level, use the levelers. Allow free air spacearound the bath to allow surface heat to convect awayfreely.Ventilation of oil fumes will require a fume hood.

4.2.2 Electrical Power

The bath requires 208-240 VAC single phase power.The higher voltage is used for running the heaters andis required to reduce the current to reasonable levels.The power connected at the junction box on the rearof the bath. The two hot legs are wired to the brownand blue wires, and the ground to the green/yellowwire according to standard convention.

4.2.3 Safety Considerations

The Hart model 6054 bath is a high temperature bath.Although safety has been a concern in its design,there are several installation and operational consid-erations to prevent fire and burns.

Install the bath in an inherently fire safe area. Thereshould not be any material around that will ignite bysetting hot probes and thermometers on it or by spill-age of the hot bath fluid.

The best floor surface is concrete. If concrete is un-available, the surface should be protected in someway from inadvertent spillage.

Do Not install the bath near flammable wall materials.

We recommend installing the bath under a fume hoodto safely remove oil fumes. It also will help to removeexcess heat. It is best to direct oil fumes away from theuser when using.

Keep all flammable liquids, fumes, gasses, etc. awayfrom the bath to prevent ignition.

Keep fire safety equipment specific to the type of me-dium handy in case they are needed.

Safe handling equipment such as leather gloves(such as welding gloves), face shields, long apron etc.are required for reasonable safety.

4.3 Setup

Inspect the probe. It should not be bent or damaged inany way.The probe used with the Model 6054 is a pre-cision PRT sensor.

The probe is to be plugged into its connector on therear of the bath and inserted fully into the hole locatednear the stirrer motor inside the motor cover.

Plug the stirrer into the receptacle located on the rearpanel of the bath marked STIRRER POWER.This re-ceptacle is switched on with the unit’s main power.

Attach a drain line to the overflow drain tube at therear of the bath behind the strirer. Use a line compati-ble with the selected fluid and maximum bath temper-ature to be used. Run the line to a similarly adequatesump.

4.3.1 Filling the Bath

The bath is shipped dry. Check inside of the test wellfor foreign matter and remove it to avoid interferencewith operation.

Installation

16

4.3.1.1 Filling the Bath With Oil

To fill the bath with oil, first be sure the drain is fullyclosed off. Check the drain assembly for tight fittings.Pour in the heat transfer fluid until it reaches a 1-inchdepth from the top of the top plate. Note: Actual depthdepends on the thermal expansion of the oil and theanticipated temperature range. The fluid volume ofthe tank is approximately 2800 cubic inches to thelevel of the primary overflow. The flowing fluid level

can be adjusted somewhat by adding to or removingfluid.The fluid level during pumping should be flowingover the rim.

The bath is now ready for operation.

4.3.2 Draining the Oil from the Bath

Installation

17

5 Operating Instructions

Operating the model 6054 constant temperature bathis not complex, but must be done according to the fol-lowing instructions.

The system must be installed and the bath filled ac-cording to the instructions in the previous section.

5.1 Quick Start

With the bath fluid in the bath and the control probe inplace, the bath is ready to be turned on. Whenswitched on, the stirring motor, the controller display-ing the bath temperature, and the heater will come on.Now set the bath to the desired temperature using thebuttons to set the temperature controller. This is ac-complished by pressing the SET button and then us-ing the UP and DOWN buttons to reach the desiredset temperature. Once the set-point desired is dis-played, press the SET button to set the bath to thenew temperature and then press the EXIT button toreturn to the temperature display (refer to the Temper-ature Controller User Flow chart Figure 4). The bathwill heat to the set temperature and begin to control.Allow several minutes for the bath to stabilize at thecontrol set-point.

The heater power switch should be set to the lowestposition necessary to provide adequate power to con-trol. Obviously, higher bath temperatures will requirehigher heater settings. The boost heater may be

switched on to bring the bath up to higher tempera-tures quickly. It must be switched off when the temper-ature is reached.

To achieve optimum control stability the proportionalband may require adjustment. The ideal proportionalband setting varies with temperature, heater setting,and fluid type.

It is advised that you operate the 6054 bath with anaccess cover or thermometer holder in place.At mosttemperatures, control stability is improved with thecover in place. At high temperatures, the use of thecover also improves safety.

To accelerate bath cooling after operation at a highertemperature, the access cover may be removed to al-low greater air cooling. It also may be possible tomake use of a dip chiller or auxiliary cooling coil to de-crease cooling times.

If the Temperature Drift mode is desired, select thatposition after adjusting the Drift Adjust to 0% to elim-inate jumps in temperature, then adjust to the antici-pated heating position. Use a bridge and strip chartrecorder or other adequate means to establish thedesired temperature drift rate as the Drift Adjust con-trol is adjusted upward. Select the LOW controlheater position for the minimum amount of heat andadd heat in increments with positions MEDIUM, ME-DIUM HIGH and HIGH as needed.

Operating Instructions

18

6 Controller Operation

This Section discusses in detail how to operate thebath temperature controller using the front controlpanel. Using the front panel key switches and LEDdisplay the user may monitor the bath temperature,set the temperature set-point in degrees C or F, moni-tor the heater output power, adjust the controller pro-portional band, set the cutout set-point, and programthe probe calibration parameters, operating parame-ters, serial and IEEE-488 interface configuration, andcontroller calibration parameters.Operation of the pri-mary functions is summarized in Figure 4.

6.1 Bath temperature

The digital LED display on the front panel allows di-rect viewing of the actual bath temperature. This tem-perature value is what is normally shown on thedisplay.The units, C or F, of the temperature value aredisplayed at the right. For example,

25.00 C Bath temperature in degreesCelsius

The temperature display function may be accessedfrom any other function by pressing the “EXIT”button.

6.2 Reset Cutout

If the over-temperature cutout has been triggeredthen the temperature display will alternately flash,

Cut-out Indicates cut-out condition

The message will continue to flash until the tempera-ture is reduced and the cutout is reset.

The cutout has two modes — automatic reset andmanual reset.The mode determines how the cutout isreset which allows the bath to heat up again. When inautomatic mode, the cutout will reset itself as soon asthe temperature is lowered below the cutout set-point.With manual reset mode the cutout must be reset bythe operator after the temperature falls below theset-point.

When the cutout is active and the cutout mode is setto manual (“reset”) then the display will flash “cutout”

until the user resets the cutout. To access the resetcutout function press the “SET” button.

S Access cutout reset function

The display will indicate the reset function.

rESEt ? Cutout reset function

Press “SET” once more to reset the cutout.

Reset cutout

This will also switch the display to the set temperaturefunction. To return to displaying the temperaturepress the “EXIT” button. If the cutout is still in theover-temperature fault condition the display will con-tinue to flash “cutout”. The bath temperature mustdrop a few degrees below the cutout set-point beforethe cutout can be reset.

6.3 Temperature Set-point

The bath temperature can be set to any value withinthe range as given in the specifications with a high de-gree of resolution. The temperature range of the par-ticular fluid used in the bath must be known by theoperator and the bath should only be operated wellbelow the upper temperature limit of the liquid. In ad-dition, the cutout temperature should also be set be-low the upper limit of the fluid.

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

6.3.1 Programmable Set-points

The controller stores 8 set-point temperatures inmemory. The set-points can be quickly recalled toconveniently set the bath to a previously programmedtemperature.

To set the bath temperature one must first select theset-point memory. This function is accessed from thetemperature display function by pressing “SET”. Thenumber of the set-point memory currently being used

Controller Operation

19


20

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

OperatingParameters

Menu

SET

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/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

Adj. CutoutReset Mode

Adj. StirrerMode

Adj. StirrerSetpoint

X 5

DO

NO

TC

HA

NG

ET

HE

SE

VAL

UE

S. S

EE

MA

NU

AL

DO

NO

TC

HA

NG

ET

HE

SE

VAL

UE

S. S

EE

MA

NU

AL

Configuration Menu

Secondary Functions

IEEE-488Option Installed

InterfaceOption Installed

Figure 4 Controller Operation Flowchart

is shown at the left on the display followed by the cur-rent set-point value.

25.00 C Bath temperature in degreesCelsius

S Access set-point memory

1. 25.0 Set-point memory 1, 25.0°Ccurrently 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 accessthe set-point value.

S Accept selected set-point memory

6.3.2 Set-point Value

The set-point value may be adjusted after selectingthe set-point memory and pressing “SET”. Theset-point value is displayed with the units, C or F, atthe left.

C 40.00 Set-point 4 value in°C

If the set-point value need not be changed then press“EXIT” to resume displaying the bath temperature. Toadjust 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 new value and access theset-point vernier. If “EXIT” is pressed instead then anychanges made to the set-point will be ignored.

S Accept new set-point value

6.3.3 Set-point vernier

The set-point value can be set with a resolution of0.01°C. The user may want to adjust the set-pointslightly to achieve a more precise bath temperature.The set-point vernier allows one to adjust the temper-ature below or above the set-point by a small amountwith very high resolution. Each of the 8 storedset-points has an associated vernier setting. The ver-nier is accessed from the set-point by pressing “SET”.The vernier setting is displayed as a 6 digit numberwith five digits after the decimal point. This is a tem-perature offset in degrees of the selected units, C or F.

0.00000 Current vernier value in°C

To adjust the vernier press “UP” or “DOWN”. Unlikemost functions the vernier setting has immediate ef-fect as the vernier is adjusted. “SET” need not bepressed.This allows one to continually adjust the bathtemperature with the vernier as it is displayed.

U Increment display

0.00090 New vernier setting

Next press “EXIT” to return to the temperature displayor “SET” to access the temperature scale units selec-tion.

S Access scale units

6.4 Temperature Scale Units

The temperature scale units of the controller may beset by the user to degrees Celsius (°C) or Fahrenheit(°F). The units will be used in displaying the bath tem-perature, set-point, vernier, proportional band, andcutout set-point.

The temperature scale units selection is accessed af-ter the vernier adjustment function 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


21

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 resumedisplaying the bath temperature.

S Set the new units and resume temperaturedisplay

6.5 Secondary Menu

Functions which are used less often are accessedwithin the secondary menu. The secondary menu isaccessed by pressing “SET” and “EXIT” simulta-neously and then releasing. The first function in thesecondary menu is the heater power display. (SeeFigure 4.)

6.6 Heater Power

The temperature controller controls the temperatureof the bath by pulsing the heater on and off. The totalpower being applied to the heater is determined bythe duty cycle or the ratio of heater on time to thepulse cycle time. This value may be estimated bywatching the red/green control indicator light or readdirectly from the digital display. By knowing theamount of heating the user can tell if the bath is heat-ing up to the set-point, cooling down, or controlling ata constant temperature. Monitoring the percentheater power will let the user know how stable thebath temperature is. With good control stability the

percent heating power should not fluctuate more than±1% within one minute.

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

S+E Access heater power in secondarymenu

12 Pct Heater power in percent

To exit out of the secondary menu press “EXIT”. Tocontinue on to the proportional band setting functionpress “SET”.

E Return to temperature display

6.7 Proportional Band

In a proportional controller such as this the heateroutput power is proportional to the bath temperatureover a limited range of temperatures around theset-point. This range of temperature is called the pro-portional band.At the bottom of the proportional bandthe heater output is 100%. At the top of the propor-tional band the heater output is 0. Thus as the bathtemperature rises the heater power is reduced, whichconsequently tends to lower the temperature backdown. In this way the temperature is maintained at afairly constant temperature.

The temperature stability of the bath depends on thewidth of the proportional band. See Figure 5. If theband is too wide the bath temperature will deviate ex-cessively from the set-point due to varying externalconditions.This is because the power output changesvery little with temperature and the controller cannotrespond very well to changing conditions or noise inthe system. If the proportional band is too narrow thebath temperature may swing back and forth becausethe controller overreacts to temperature variations.For best control stability the proportional band mustbe set for the optimum width.

The optimum proportional band width depends onseveral factors among which are fluid volume, fluidcharacteristics (viscosity, specific heat, thermal con-ductivity), operating temperature, and stirring. Thusthe proportional band width may require adjustmentfor best bath stability when any of these conditions


22

change. Of these, the most significant factors affect-ing the optimum proportional band width are the fluidviscosity and thermal noise due to difference in tem-perature between the fluid and ambient. The propor-tional band should be wider when the fluid viscosity ishigher because of the increased response time andalso when noise is greater.

The proportional band width is easily adjusted fromthe bath front panel. The width may be set to discretevalues in degrees C or F depending on the selectedunits. The optimum proportional band width settingmay be determined by monitoring the stability with ahigh resolution thermometer or with the controllerpercent output power display.Narrow the proportionalband width to the point at which the bath temperaturebegins to oscillate and then increase the band widthfrom this point to 3 or 4 times wider.

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



S Access proportional band

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 cutoutset-point press “SET”. Pressing “EXIT” will exit thesecondary menu ignoring any changes just made tothe proportional band value.

S Accept the new proportional band setting

6.8 Cutout

As a protection against software or hardware fault,shorted heater triac, or user error, the bath isequipped with an adjustable heater cutout device thatwill shut off power to the heater if the bath tempera-ture exceeds a set value.This protects the heater andbath materials from excessive temperatures and,


23

Proportional Band too Narrow Proportional Band too Wide

Optimum Proportional Band

Figure 5 Bath temperature flucuations at various proportional band settings.

most importantly, protects the bath fluids from beingheated beyond the safe operating temperature pre-venting hazardous vaporization, breakdown, or igni-tion of the liquid. The cutout temperature isprogrammable by the operator from the front panel ofthe controller. It must always be set below the uppertemperature limit of the fluid and no more than 10 de-grees above the upper temperature limit of the bath.

If the cutout is activated because of excessive bathtemperature then power to the heater will be shut offand the bath will cool. The bath will cool until itreaches a few degrees below the cutout set-pointtemperature. At this point the action of the cutout isdetermined by the setting of the cutout mode parame-ter. The cutout has two modes — automatic reset ormanual reset. If the mode is set to automatic, then thecutout will automatically reset itself when the bathtemperature falls below the reset temperature allow-ing the bath to heat up again. If the mode is set to man-ual, then the heater will remain disabled until the usermanually resets the cutout.

The cutout set-point may be accessed within the sec-ondary menu. Press “SET” and “EXIT” to enter thesecondary menu and show the heater power. Thenpress “SET” twice to access the cutout set-point.



S Access proportional band

Pb=0.101C Proportional band setting

S Access cutout set-point

CO= 210C Cutout set-point

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

D Decrement display

CO= 95C New cutout set-point

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

S Accept cutout set-point

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

6.9 Controller Configuration

The controller has a number of configuration and op-erating options and calibration parameters which areprogrammable via the front panel. These are ac-cessed from the secondary menu after the cutoutset-point function by pressing “SET”. The display willprompt with “COnFIG”. Press “SET” once more.There are 5 sets of configuration parameters — probeparameters, operating parameters, serial interfaceparameters, IEEE-488 interface parameters, andcontroller calibration parameters. The menus are se-lected using the “UP” and “DOWN” keys and thenpressing “SET”. See Figure 4.

6.10 Probe Parameters Menu

The probe parameter menu is indicated by,

PrObE Probe parameters menu

Press “SET” to enter the menu. The probe parame-ters menu contains the parameters, R0 and ALPHA,which characterize the resistance-temperature rela-tionship of the platinum control probe.These parame-ters may be adjusted to improve the accuracy of thebath.This procedure is explained in detail in Section.

The probe parameters are accessed by pressing“SET” after the name of the parameter is displayed.The value of the parameter may be changed using the“UP” and “DOWN” buttons. After the desired value isreached press “SET” to set the parameter to the newvalue. Pressing “EXIT” will cause the parameter to beskipped ignoring any changes that may have beenmade.

6.10.1 R0

This probe parameter refers to the resistance of thecontrol probe at 0°C. Normally this is set for 100.000ohms.


24

6.10.2 ALPHA

This probe parameter refers to the average sensitivityof the probe between 0 and 100°C. Normally this isset for 0.00385°C-1.

6.11 Operating Parameters

The operating parameters menu is indicated by,

PAr Operating parameters menu

Press “SET” to enter the menu. The operating param-eters menu contains the cutout reset mode parame-ter.

6.11.1 Cutout Reset Mode

The cutout reset mode determines whether the cutoutresets automatically when the bath temperaturedrops to a safe value or must be manually reset by theoperator.

The parameter is indicated by,

CtorSt Cutout reset mode parameter

Press “SET” to access the parameter setting.Normally the cutout is set for automatic mode.

Cto=Auto Cutout set for automatic reset

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

Cto=rSt Cutout set for manual reset

6.11.2 Stirrer Mode Select

This parameter along with the Stirrer set-point allowthe user to set the temperature at which the stirrermotor is activated.This setting is generally used whensalt is used for the bath medium. For example, youcan set the mode to “auto” and the temperature to200°C. This allows the stirrer motor to shut off andturn on only when the salt is a liquid (>200°C) prevent-ing the stirrer motor from overheating and damage.

The parameter is indicated by,

Str Act Stirrer mode selection parame-ter

Press “SET” to access the parameter setting.

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

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

6.11.3 Stirrer set-point

Allows setting of the temperature above which thestirrer motor will activate when the stirrer activation isset to automatic.

To access the paramter press “SET” from the stirreractivation parameter. set-point mode selection pa-rameter is indicated by,

Str SEt Stirrer motor activation set-pointparameter

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 new value.

6.12 Serial InterfaceParameters

The serial RS-232 interface parameters menu is indi-cated by,

SErIAL Serial RS-232 interface param-eters menu

The serial interface parameters menu contains pa-rameters which determine the operation of the serialinterface. These controls only apply to baths fittedwith the serial interface. The parameters in the menuare — BAUD rate, sample period, duplex mode, andlinefeed.


25

6.12.1 BAUD Rate

The BAUD rate is the first parameter in the menu.TheBAUD rate setting determines the serial communica-tions transmission rate.

The BAUD rate parameter is indicated by,

BAUd Serial BAUD rate parameter

Press “SET” to choose to set the BAUD rate. The cur-rent BAUD rate value will then be displayed.

1200 b Current BAUD rate

The BAUD rate of the bath serial communicationsmay be programmed to 300,600,1200, or 2400BAUD.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 operation and skip to the next pa-rameter in the menu.

6.12.2 Sample Period

The sample period is the next parameter in the serialinterface parameter menu. The sample period is thetime period in seconds between temperature mea-surements transmitted from the serial interface. If thesample rate is set to 5 for instance then the bath willtransmit the current measurement over the serial in-terface approximately every five seconds. The auto-matic sampling is disabled with a sample period of 0.The sample period is indicated by,

SAmPLE Serial sample period parameter

Press “SET” to choose to set the sample period. Thecurrent sample period value will be displayed.

SA= 1 Current sample period (sec-onds)

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

SA= 60 New sample period

6.12.3 Duplex Mode

The next parameter is the duplex mode. The duplexmode may be set to full duplex or half duplex. With fullduplex any commands received by the bath via theserial interface will be immediately echoed or trans-mitted back to the device of origin. With half duplexthe commands will be executed but not echoed. Theduplex 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

6.12.4 Linefeed

The final parameter in the serial interface menu is thelinefeed mode. This parameter enables (on) or dis-ables (off) transmission of a linefeed character (LF,ASCII 10) after transmission of any carriage-return.The linefeed parameter is indicated by,

LF Serial linefeed parameter

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

6.13 IEEE-488 ParametersMenu

Baths may optionally be fitted with an IEEE-488 GPIBinterface. In this case the user may set the interfaceaddress within the IEEE-488 parameter menu. Thismenu does not appear on baths not fitted with the in-terface. The menu is indicated by,


26

IEEE IEEE-488 parameters menu

Press “SET” to enter the menu.

6.13.1 IEEE-488 Address

The IEEE-488 interface must be configured to use thesame address as the external 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 ad-dress

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

Add= 15 New IEEE-488 interface ad-dress

6.14 Calibration Parameters

The operator of the bath controller has access to anumber of the bath calibration constants, namelyCTO, C0, CG, H, and L. These values are set at thefactory and must not be altered. The correct valuesare important to the accuracy and proper and safe op-eration of the bath. Access to these parameters isavailable to the user only so that in the event that thecontroller’s memory fails the user may restore thesevalues to the factory settings. The user should have alist of these constants and their settings with the man-ual.

DO NOT change the values of the bath calibrationconstants from the factory set values.The correctsetting of these parameters is important to thesafety 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.

6.14.1 CTO

Parameter CTO sets the calibration of the over-tem-perature cutout. This is not adjustable by software butis adjusted with an internal potentiometer. For the6054 bath this parameter should read between 560and 570.

6.14.2 CO and CG

These parameters calibrate the accuracy of the bathset-point. These are programmed at the factory whenthe bath is calibrated. Do not alter the value of theseparameters. If the user desires to calibrate the bath forimproved accuracy then calibrate R0 and ALPHA ac-cording to the procedure given in Section 10.

6.14.3 H and L

These parameters set the upper and lower set-pointlimits of the bath.DO NOT change the values of theseparameters from the factory set values. To do so maypresent danger of the bath overheating and causingdamage or fire.

6.15 Operation Summary

A complete flowchart of controller operation is shownin Figure 4. This chart may be reproduced and usedas a reference and operating guide.


27

7 Digital Communication Interface

If supplied with the option, the 6025/6035 bath is ca-pable of communicating with and being controlled byother equipment through the digital interface. Twotypes of digital interface are available — the RS-232serial interface and the IEEE-488 GPIB interface.

7.1 Serial Communications

The bath may be installed with an RS-232 serial inter-face that allows serial digital communications overfairly long distances. With the serial interface the usermay access any of the functions, parameters and set-tings discussed in Section 6 with the exception of theBAUD rate setting. The serial interface operates with8 data bits, 1 stop bit, and no parity. The use of ashielded communications cable is recommended.

7.1.1 Wiring

The serial communications cable attaches to the baththrough the D-9 connector on the back panel.Figure 6shows the pin-out of this connector and suggestedcable wiring.

7.1.2 Setup

Before operation, the serial interface of the bath mustfirst be set up by programming the BAUD rate andother configuration parameters. These parametersare programmed within the serial interface menu.Theserial interface parameters menu is outlined in Figure4 on page 20.

To enter the serial parameter programming mode firstpress “EXIT” while pressing “SET” and release to en-ter the secondary menu. Press “SET” repeatedly untilthe display reads “ProbE”. This is the menu selection.Press “UP” repeatedly until the serial interface menuis indicated with “SErIAL”.Finally press “SET” to enterthe serial interface parameters menu. In the serial in-terface parameters menu are the BAUD rate, samplerate, duplex mode, and linefeed parameters.

7.1.2.1 BAUD rate

The BAUD rate is the first parameter in the menu.Thedisplay will prompt with the BAUD rate parameter by

showing “BAUd”. Press “SET” to choose to set theBAUD rate. The current BAUD rate value will then bedisplayed. The BAUD rate of the serial communica-tions may be programmed to 300, 600, 1200, or 2400BAUD. The BAUD rate is pre-programmed to 1200BAUD.Use “UP” or “DOWN” to change the BAUD ratevalue. Press “SET” to set the BAUD rate to the newvalue or “EXIT” to abort the operation and skip to thenext parameter in the menu.

7.1.2.2 Sample Period

The sample period is the next parameter in the menuand prompted with “SAmPLE”. The sample period isthe time period in seconds between temperaturemeasurements transmitted from the serial interface. Ifthe sample rate is set to 5 for instance then the bathwill transmit the current measurement over the serial

Digital Communication Interface

28

1 NC2 RxD3 TxD4 NC5 GND6 NC7 RTS8 CTS9 NC



2 TxD3 RxD4 RTS5 CTS67 GND820

RS-232 Cable Wiring forIBM PC and Compatibles

6054 ControllerConnector(DB 9-Pin)

6054 ControllerConnector(DB 9-Pin)

Computer (DTE)Connector

(DB 25-Pin)

Computer (DTE)Connector(DB 9-Pin)

Figure 6 Serial Cable Wiring Diagram

interface approximately every five seconds.The auto-matic sampling is disabled with a sample period of 0.Press “SET” to choose to set the sample period. Ad-just the period with “UP” or “DOWN” and then use“SET” to set the sample rate to the displayed value.

7.1.2.3 Duplex Mode

The next parameter is the duplex mode indicated with“dUPL”. The duplex mode may be set to half duplex(“HALF”) or full duplex (“FULL”). With full duplex anycommands received by the bath via the serial inter-face will be immediately echoed or transmitted backto the device of origin.With half duplex the commandswill be executed but not echoed. The default setting isfull duplex. The mode may be changed using “UP” or“DOWN” and pressing “SET”.

7.1.2.4 Linefeed

The final parameter in the serial interface menu is thelinefeed mode. This parameter enables (“On”) or dis-ables (“OFF”) transmission of a linefeed character(LF, ASCII 10) after transmission of any carriage-re-turn. The default setting is with linefeed on. The modemay be changed using “UP” or “DOWN” and pressing“SET”.

7.1.3 Serial Operation

Once the cable has been attached and the interfaceset up properly the controller will immediately begintransmitting temperature readings at the pro-grammed rate. The serial interface operates with 8data bits, 1 stop bit, and no parity. The set-point andother commands may be sent to the bath via the serialinterface to set the bath and view or program the vari-ous parameters. The interface commands are dis-cussed in Section 7.3. All commands are ASCIIcharacter strings terminated with a carriage-returncharacter (CR, ASCII 13).

7.2 IEEE-488 Communication(optional)

The IEEE-488 interface is available as an option.Baths supplied with this option may be connected to aGPIB type communication bus which allows many in-struments to be connected and controlled simulta-neously.

7.2.1 Setup and Address Selection

To use the IEEE-488 interface first connect anIEEE-488 standard cable to the back of the bath.

Next set the device address. This parameter is pro-grammed within the IEEE-488 interface menu. To en-ter the IEEE-488 parameter programming menu firstpress “EXIT” while pressing “SET” and release to en-ter the secondary menu. Press “SET” repeatedly untilthe display reaches “PrObE”. This is the menu selec-tion. Press “UP” repeatedly until the IEEE-488 inter-face menu is indicated with “IEEE”. Press “SET” toenter the IEEE-488 parameter menu. The IEEE-488menu contains the IEEE-488 address parameter.

The IEEE-488 address is prompted with “AddrESS”.Press “SET” to program the address. The default ad-dress is 22. Change the device address of the bath ifnecessary to match the address used by the commu-nication equipment by pressing “UP” or “DOWN” andthen “SET”.

7.2.2 IEEE-488 Operation

Commands may now be sent via the IEEE-488 inter-face to read or set the temperature or access othercontroller functions. All commands are ASCII charac-ter strings and are terminated with a carriage-return(CR, ASCII 13). Interface commands are listed below.

7.3 Interface Commands

The various commands for accessing the bath con-troller functions via the digital interfaces are listed inthis section (see Table 2).These commands are usedwith both the RS-232 serial interface and theIEEE-488 GPIB interface. In either case the com-mands are terminated with a carriage-return charac-ter.The interface makes no distinction between upperand lower case letters, hence either may be used.Commands may be abbreviated to the minimum num-ber of letters which determines a unique command. Acommand may be used to either set a parameter ordisplay a parameter depending on whether or not avalue is sent with the command following a “=”charac-ter. For example “s”<CR> will return the currentset-point and “s=50.00”<CR> will set the set-point(set-point 1) to 50.00 degrees.

In Table 2, characters or data within brackets, “[” and“]”, are optional for the command.A slash, “/”, denotes

29



30

Command DescriptionCommandFormat

CommandExample Returned

ReturnedExample

AcceptableValues

Display TemperatureRead 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 Instrument Range

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 toCelsius

u[nits]=c u=c

Set temperature units toFahrenheit

u[nits]=f u=f

Secondary MenuRead proportional band setting pr[op-band] pr pr: 999.9 pr: 15.9

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

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

Set cutout setting: c[utout]=n/r[eset]

Set cutout to n degrees c[utout]=n c=500 TemperatureRange

Reset cutout now c[utout]=r[eset] c=r

Read heater power(duty cycle)

po[wer] po po: 9999 po: 1

Configuration MenuProbe 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 calibration parameter al[pha] al al: 9.9999999 al: 0.0038573

Set ALPHA calibration parameter to n al[pha]=n al=0.0038433 .00370 to .00399

Operating Parameters Menu

Read cutout mode cm[ode] cm cm: {xxxx} cm: AUTO

Set cutout mode: cm[ode]=r[eset]/a[uto] RESET or AUTO

Set cutout to be resetmanually-

cm[ode]=r[eset] cm=r

Set cutout 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 striier activationmode to on

smod=o smod=o

Set striier 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 instrument range

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

Table 2 Communications Commands

alternate characters or data. Numeric data, denotedby “n”, may be entered in decimal or exponential nota-tion. Bold type characters are literal characters whilenormal type symbolizes data. Characters are shownin lower case although upper case may be used.Spaces may be added within command strings andwill simply be ignored. Backspace (BS, ASCII 8) maybe used to erase the previous character. A terminat-ing CR is implied with all commands.

7.4 Power Commands

The digital interface is capable of controlling the heat-ing functions so that the bath can be remotely oper-ated at any temperature within the range of the bath.To allow the interface to control the heating, the frontpanel controls are disabled by 1) switching the heatercontrol to “OFF”, and 2) switching the boost heater


31

Command DescriptionCommandFormat

CommandExample Returned

ReturnedExample

AcceptableValues

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

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 a carriagereturn and linefeed. Then the value is returned as indicated in the RETURNED column.

Communications Commands, cont.

switch to “OFF”.Otherwise, the interface would not beable to switch these functions off. The 6054 bath hasfive control functions with the digital interface. Theseare controls for heaters 1, 2, 3, and 4, each 250 W,and the boost heater which is 1000 W.Heater 1 poweris variable with the DRIFT control on the front panel.The boost heater should only be used for quicklyheating the bath up to a high temperature and not forcontrolling at a constant temperature.

Serial commands “F1” through “F5” control the heat-ers 1 through 4 and the boost heater individually.These commands are used to turn the heaters on oroff or to read the states of the heaters.Sending a com-mand with parameter “1” turns the heater on.Parame-ter “0” turns the heater off. No parameter returns thestate, “1” for on or “0” for off. For example “F1=1”<RE-TURN> turns on heater 1. “F1”<RETURN> (no pa-

rameter) will return “f1:1” or “f1:0” depending onwhether heater 1 is on or off respectively.

Since unlike the front panel heater control, whichturns on multiple heaters to achieve the desiredpower level, the interface commands control the heat-ers individually, multiple commands must be issued toset the desired amount of power.Table 4 lists the com-mands which should be given to set various powerlevels. Power is variable with the front panel DRIFTcontrol when heater 1 (F1) is turned on.

7.5 Heater Settings for Control

Suggested heater control settings for various rangesare suggested in Table 5 below.


32

POWER F1 F2 F3 F4 F5

OFF 0 0 0 0 0

0–250 W LOW 1 0 0 0 0

250–500 WMEDIUM

1 1 0 0 0

500–750 WMEDIUM HIGH

1 1 1 0 0

750–1000 WHIGH

1 1 1 1 0

‘750 W BOOST 1 1 1 1 1

Table 4 Heater Power Settings

Range Controls50°C–125°C LOW - Heater 1 on, heaters 2–4

and boost heater off125°C–200°C MEDIUM - Heaters 1 and 2 on,

heater 3, 4, and boost heater off200°C–275°C MEDIUM HIGH - Heaters 1–3 on

and heater 4 and boost heater off275°C–325°C HIGH - Heaters 1–4 and boost

heater on

Table 5 Suggested Heater Settings

8 Bath Calibration

In some instances the user may want to calibrate thebath to improve the temperature set-point accuracy.Calibration is done by adjusting the controller probecalibration constants R0 and ALPHA so that the tem-perature of the bath as measured with a standardthermometer agrees more closely with the bathset-point. The thermometer used must be able tomeasure the bath fluid temperature with higher accu-racy than the desired accuracy of the bath.By using agood thermometer and carefully following procedurethe bath can be calibrated to an accuracy of betterthan 0.02°C over a range of 100 degrees.

8.1 Calibration Points

In calibrating the bath R0 and ALPHA are adjusted tominimize the set-point error at each of two differentbath temperatures. Any two reasonably separatedbath temperatures may be used for the calibrationhowever best results will be obtained when using bathtemperatures which are just within the most usefuloperating range of the bath.The further apart the cali-bration temperatures the larger will be the calibratedtemperature range but the calibration error will alsobe greater over the range. If for instance 50°C and150°C are chosen as the calibration temperaturesthen the bath may achieve an accuracy of say±0.03°C over the range 40 to 160°C. Choosing 80°C

Bath Calibration

33

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

0086 800 0157 1200

1200 800000385′ = − − −

−+( . ) . ( . ) .

. ..

x x1 100000 100115

⎡

⎣⎢

⎤

⎦⎥ =. .

Compute ALPHA,

ALPHA′ = + − − +( . . )( . ) ( . . )(1 000385 1200 0157 1 000385 800x x −−

+⎡

⎣⎢

⎤

⎦⎥ =0086

1200 8001 000385 00038387

. )

. .. .

Figure 7 Calibration Example

and 120°C may allow the bath to have a better accu-racy of maybe ±0.01°C over the range 75 to 125°C butoutside that range the accuracy may be only ±0.05°C.

8.2 Measuring the Set-pointError

The first step in the calibration procedure is to mea-sure the temperature errors (including sign) at the twocalibration temperatures. First set the bath to thelower set-point which we will call tL.Wait for the bath toreach the set-point and allow 15 minutes to stabilizeat that temperature. Check the bath stability with thethermometer.When both the bath and the thermome-ter have stabilized measure the bath temperaturewith the thermometer and compute the temperatureerror errL which is the actual bath temperature minusthe set-point temperature. If for example the bath isset for a lower set-point of tL=50°C and the bathreaches a measured temperature of 49.7°C then theerror is -0.3°C.

Next, set the bath for the upper set-point tH and afterstabilizing measure the bath temperature and com-pute the error errH. For our example we will supposethe bath was set for 150°C and the thermometer mea-sured 150.1°C giving an error of +0.1°C.

8.3 Computing R0 and ALPHA

Before computing the new values for R0 and ALPHAthe current values must be known.The values may befound by either accessing the probe calibration menufrom the controller panel or by inquiring through thedigital interface. The user should keep a record ofthese values in case they may need to be restored in

the future. The new values R0′ and ALPHA′ are com-puted by entering the old values for R0 and ALPHA,the calibration temperature set-points tL and tH, andthe temperature errors errL and errH into the followingequations,

R err t err tt t

ALPHA RH L L H

H L

0 1 0⎡ = −−

+⎡

⎣⎢

⎤

⎦⎥

ALPHA ALPHA t err ALPHA t errt t

H L L H

H L

⎡ = + − +−

+⎡

⎣⎢

⎤

⎦

( ) ( )1 11⎥ ALPHA

If for example R0 and ALPHA were previously set for100.000 and 0.0038500 respectively and the data fortL, tH, errL, and errH were as given above then the newvalues R0′ and ALPHA′ would be computed as100.193 and 0.0038272 respectively. Program thenew values R0 and ALPHA into the controller. Checkthe calibration by setting the temperature to tL and tHand measuring the errors again. If desired the calibra-tion procedure may be repeated again to further im-prove the accuracy.

8.4 Calibration Example

The bath is to be used between 75 and 125°C and it isdesired to calibrate the bath as accurately as possiblefor operation within this range. The current values forR0 and ALPHA are 100.000 and 0.0038500 respec-tively. The calibration points are chosen to be 80.00and 120.00°C. The measured bath temperatures are79.843 and 119.914°C respectively. Refer to Figure 7for applying equations to the example data and com-puting the new probe constants.

Bath Calibration

34

9 Bath Heat Transfer Fluid

Many fluids will work with 6054 bath. Choosing a fluidrequires consideration of many important character-istics of the fluid. Among these are temperaturerange, viscosity, specific heat, thermal conductivity,thermal expansion, electrical conductivity, fluid life-time, safety, and cost.

9.1 Temperature Range

One of the most important characteristics to consideris the temperature range of the fluid. Few fluids workwell throughout the entire temperature range of thebath. The temperature at which the bath is operatedmust always be within the safe and useful tempera-ture range of the fluid used. The lower temperaturerange of the fluid is determined either by the freezepoint of the fluid or the temperature at which the vis-cosity becomes too great. The upper temperature isusually limited by vaporization, flammability, or chem-ical breakdown of the fluid. Vaporization of the fluid athigher temperatures may adversely affect tempera-ture stability because of cool condensed fluid drippinginto the bath from the lid.

The bath temperature should be limited by setting thesafety cutout so that the bath temperature cannot ex-ceed the safe operating temperature limit of the fluid.

9.2 Viscosity

Viscosity is a measure of the thickness of a fluid orhow easily it can be poured and mixed. Viscosity af-fects the temperature uniformity and stability of thebath. With lower viscosity, fluid mixing is better there-fore creating a more uniform temperature throughoutthe bath. This improves the bath response time whichallows it to maintain a more constant temperature.Forgood control the viscosity should be less than 10centistokes. The practical upper limit of allowable vis-cosity is about 50 centistokes. Viscosity greater thanthis causes very poor control stability because of poorstirring and may also overheat or damage the stirringmotor. Viscosity may vary greatly with temperature,especially with oils.

When using fluids with higher viscosities the control-ler proportional band may need to be increased to

compensate for the reduced response time. Other-wise the temperature may begin to oscillate.

9.3 Specific heat

Specific heat is the measure of the heat storage abil-ity of the fluid.Specific heat, to a small degree, affectsthe control stability. It also affects the heating andcooling rates. Generally, a lower specific heat meansquicker heating and cooling. The proportional bandmay require some adjustment depending on the spe-cific heat of the fluid.

9.4 Thermal Conductivity

Thermal conductivity measures how easily heat flowsthrough the fluid. Thermal conductivity of the fluid af-fects the control stability, temperature uniformity, andtemperature settling time. Fluids with higher conduc-tivity distribute heat more quickly and evenly improv-ing bath performance.

9.5 Thermal Expansion

Thermal expansion describes how much the volumeof the fluid changes with temperature. Thermal ex-pansion of the fluid must be considered since the in-crease in fluid volume as the bath temperatureincreases may cause overflow.Excessive thermal ex-pansion may also be undesirable in applicationswhere constant liquid level is important. Many fluidsincluding oils have significant thermal expansion.

9.6 Electrical Resistivity

Electrical resistivity describes how well the fluid insu-lates against the flow of electric current. In some ap-plications, such as measuring the resistance of baretemperature sensors, it may be important that little orno electrical leakage occur through the fluid. In suchconditions choose a fluid with very high electrical re-sistivity.

Bath Heat Transfer Fluid

35

9.7 Fluid lifetime

Many fluids degrade over time because of vaporiza-tion, water absorption, gelling, or chemical break-down. Often the degradation becomes significantnear the upper temperature limit of the fluid, substan-tially reducing the fluid’s lifetime.

9.8 Safety

When choosing a fluid always consider the safety is-sues associated. Obviously where there are extremetemperatures there can be danger to personnel andequipment. Fluids may also be hazardous for otherreasons. Some fluids may be considered toxic. Con-tact with eyes, skin, or inhalation of vapors may causeinjury. A proper fume hood must be used if hazardousor bothersome vapors are produced.

Fluids may be flammable and require special firesafety equipment and procedures.

An important characteristic of the fluid to consider isthe flash point. The flash point is the temperature atwhich there is sufficient vapor given off so that whenthere is adequate oxygen present and an ignitionsource is applied the vapor will ignite. This does notnecessarily mean that fire will be sustained at theflash point. The flash point may be either of the opencup or closed cup type. Either condition may occur ina bath situation.

The open cup flash point is measured under the con-dition of vapors escaping the tank. The closed cupflash point is measured with the vapors being con-tained within the tank. Since oxygen and an ignitionsource is less available inside the tank the closed cupflash point will be lower than the open cup flash point.

Remember also that environmentally hazardous flu-ids require special disposal according to applicablefederal or local laws after use.

9.9 Cost

Cost of bath fluids may vary greatly, from cents pergallon for water to hundreds of dollars per gallon forsynthetic oils. Cost may be an important consider-ation when choosing a fluid.

9.9.1 Commonly used fluids

Below is a description of some of the more commonlyused fluids and their characteristics.

9.9.2 Water

Water is often used because of its very low cost, itsavailability, and its excellent temperature control char-acteristics. Water has very low viscosity and goodthermal conductivity and heat capacity which makesit among the best fluids for good control stability atlower temperatures. Temperature stability is muchpoorer at higher temperatures because water con-denses on the lid, cools and drips into the bath.Wateris safe and relatively inert. The electrical conductivityof water may prevent its use in some applications.Water has a limited temperature range, from a few de-grees above 0°C to a few degrees below 100°C. Athigher temperatures evaporation becomes signifi-cant. Water used in the bath should be distilled ordeionized to prevent mineral deposits.Consider usingan algicide chemical in the water to prevent contami-nation.

9.9.3 Ethylene Glycol

The temperature range of water may be extended byusing a solution of 1 part water and 1 part ethyleneglycol (antifreeze).The characteristics of the ethyleneglycol-water solution are similar to water but withhigher viscosity. Use caution with ethylene glycolsince this fluid is very toxic. Ethylene glycol must bedisposed of properly.

9.9.4 Mineral Oil

Mineral oil or paraffin oil is often used at moderatetemperatures above the range of water. Mineral oil isrelatively inexpensive. At lower temperatures mineraloil is quite viscous and control may be poor. At highertemperatures vapor emission becomes significant.The vapors may be dangerous and use of a fumehood is highly recommended. As with most oils ,min-eral oil will expand as temperature increases, there-fore, be careful not to fill the bath too full that itoverflows when heated. The viscosity and thermalcharacteristics of mineral oil is poorer than water sotemperature stability will not be as good. Mineral oilhas very low electrical conductivity. Use caution with


36

mineral oil since it is flammable and may also causeserious injury if inhaled or ingested.

9.9.5 Silicone oil

Silicone oils are available which offer a much wideroperating temperature range than mineral oil. Likemost oils, silicone oils have temperature control char-acteristics which are somewhat poorer than water.The viscosity changes significantly with temperatureand thermal expansion also occurs. These oils have

very high electrical resistivity. Silicone oils are fairlysafe and non-toxic. Silicone oils are fairly expensive.

9.9.6 Heat Transfer Salt

Heat transfer salt is often used at high bath tempera-tures.Salt has a very high upper temperature limit anda wide useful temperature range. Salt may be usedfrom its freezing point at 145°C up to the upper tem-perature limit of the bath.Viscosity is low, especially athigher temperatures. Salt when melted has very lowelectrical resistivity. Salt may be corrosive to some


37

Fluid(# = HartPart No.)

LowerTemperatur

e Limit*

UpperTemperatur

e Limit*FlashPoint

Viscosity(centistokes)

SpecificGravity

SpecificHeat

(cal/g/°C)

ThermalConductivity(cal/s/cm/°C)

ThermalExpansion(cm/cm/°C)

Resistivity(1012 -cm )

Halocarbon 0.8#5019

–90°C (v)** 70°C (e) NONE 5.7 @ –50°C0.8 @ 40°C0.5 @ 70°C

1.71 @ 40°C 0.2 0.0004 0.0011

Methanol –96°C (fr) 60°C (b) 54°C 1.3 @ –35°C0.66 @ 0°C0.45 @ 20°C

0.810 @ 0°C0.792 @ 20°C

0.6 0.0005 @20°C

0.0014 @25°C

Water 0°C (fr) 95°C (b) NONE 1 @ 25°C0.4 @ 75°C

1.00 1.00 0.0014 0.0002 @25°C

EthyleneGlycol—50%#5020

–35°C (fr) 110°C (b) NONE 7 @ 0°C2 @ 50°C

0.7 @ 100°C

1.05 0.8 @ 0°C 0.001

Mineral Oil 40°C (v) 190°C (fl) 190°C 15 @ 75°C5 @ 125°C

0.87 @ 25°C0.84 @ 75°C0.81 @ 125°C

0.48 @ 25°C0.53 @ 75°C0.57 @ 125°C

0.00025 @25°C

0.0007 @50°C

5 @ 25°C

Dow Corning200.5Silicone Oil

–40°C (v)** 133°C (fl, cc) 133°C 5 @ 25°C 0.92 @ 25°C 0.4 0.00028 @25°C

0.00105 1000 @ 25°C10 @ 150°C

Dow Corning200.10#5012

–35°C (v)** 165°C (fl, cc) 165°C 10 @ 25°C3 @ 135°C

0.934 @ 25°C 0.43 @ 40°C0.45 @ 100°C

0.482 @200°C

0.00032 @25°C

0.00108 1000 @ 25°C50 @ 150°C

Dow Corning200.20#5013

7°C (v) 230°C (fl, cc) 230°C 20 @ 25°C 0.949 @ 25°C 0.370 @ 40°C0.393 @100°C

0.420 @200°C

0.00034 @25°C

0.00107 1000 @ 25°C50 @ 150°C

Dow Corning200.50Silicone Oil

25°C (v) 280°C (fl, cc) 280°C 20 @ 25°C 0.96 @ 25°C 0.4 0.00037 @25°C

0.00104 1000 @ 25°C50 @ 150°C

Dow Corning550#5016

70°C (v) 232°C (fl, cc)300°C (fl, oc)

232°C 50 @ 70°C10 @ 104°C

1.07 @ 25°C 0.358 @ 40°C0.386 @100°C

0.433 @200°C

0.00035 @25°C

0.00075 100 @ 25°C1 @ 150°C

Dow Corning710#5017

80°C (v) 302°C (fl, oc) 302°C 50 @ 80°C7 @ 204°C

1.11 @ 25°C 0.363 @ 40°C0.454 @100°C

0.505 @200°C

0.00035 @25°C

0.00077 100 @ 25°C1 @ 150°C

Dow Corning210-HSilicone Oil

66°C (v) 315°C (fl, oc) 315°C 50 @ 66°C14 @ 204°C

0.96 @ 25°C 0.34 @100°C

0.0003 0.00095 100 @ 25°C1 @ 150°C

Table 6 Table of Bath Fluids

materials. Salt will quickly oxidize the coating on gal-vanized metal. Carbon steel may be used with salt upto 450°C. Beyond this temperature stainless steel isrecommended.

CAUTION: Keep all combustible materials awayfrom the bath when using salt. Operate the bathon a heat-proof surface such as concrete.Providea means of safely containing any spills which mayoccur.

The greatest safety concern with liquid salt is with itshigh temperature. The fluid provides a source of heat


38

–100°C 0°C 100°C 200°C 300°C 400°C 500°C 600°C

BP - Boiling PointCS - CentistokesEP - Evaporation Point, fluid loss

due to evaporation too high.FL - Flash PointFR - Freeze PointPP - Pour Point

Shaded area represents usable range of fluid starting at 50centistokes. Lighter shading represents decreasing viscosity, whilevaporization and decomposition increase.

Black area represents liquid range with excessive viscosity.

Range over which a fume hood is recommended.

10 CS FL 302°CPPSilicone Oil710

Silicone Oil200.50 10 CS FL 280°CPP




10 CS FL 230°CSilicone Oil550 PP

10 CS EPHalocarbon0.8

FL 177°CMineral Oil

BPWater FR

BPMethanol FR (Pure)

10 CS BPEthylene Glycol50/50 with H O2

FR

DecompositionStarts

Bath Salt FR

10 CS

FL 12°C

Figure 8 Chart showing usable range of various fluids.

which can ignite or destroy materials. Especially dan-gerous are spills since the hot fluid is difficult to con-tain.Salt may also cause steam explosions if it comesinto contact with water. Using salt requires specialcaution. Read carefully the information and safetydata sheets provided with the salt.Use of a fume hoodis recommended to remove any products of decom-position or oxidation.

Because salt is solid at room temperature special pro-cedures are required in using the bath with salt. Thebath has been designed so that the stir motor will notturn on until the bath has reached the temperature forthe salt to liquify.

Solid salt has poor thermal conductivity. Only operatethe bath with the “HEATER” switch on position “LOW”until the salt is melted.Using higher heater power mayover-heat and damage the bath heaters. The heaterswill only run at 25% power until the bath reaches200°C. This helps to protect the heaters during melt-ing of the salt. This is especially possible when heat-ing salt which has solidified and contracted leavinggaps between the bath walls and the salt.

Salt is supplied in a pink granular form. Fill the bathgradually as the salt heats and melts. Because of theheat required to melt the salt this is a slow processand may take 10 hours or more. Fill the bath until theliquid is a few inches below the lid. The level will riseas much as two inches as it is heated to the uppertemperature limit.

9.10 Fluid CharacteristicsCharts

Table 6 and Figure 8 on pages 37 and 38 have beencreated to provide help in selecting a heat exchangefluid media for your constant temperature bath.Thesecharts provide both a visual and numerical represen-tation of most of the physical qualities important inmaking a selection. The list is not all inclusive. Theremay be other useful fluids not shown in this listing.

The charts include information on a variety of fluidswhich are often used as heat transfer fluid in baths.Because of the temperature range some fluids maynot be useful with your bath.

9.10.1 Limitations and Disclaimer

The information given in this manual regarding fluidsis intended only to be used as a general guide inchoosing a fluid. Though every effort has been madeto provide correct information we cannot guaranteeaccuracy of data or assure suitability of a fluid for aparticular application.Specifications may change andsources sometimes offer differing information. HartScientific cannot be liable for any personal injury ordamage to equipment, product or facilities resultingfrom the use of these fluids.The user of the bath is re-sponsible for collecting correct information, exercis-ing proper judgement, and insuring safe operation.Operating near the limits of certain properties such asthe flash point or viscosity can compromise safety orperformance. Your company’s safety policies regard-ing flash points, toxicity, and such issues must be con-sidered. You are responsible for reading the MSDS(material safety data sheets) and acting accordingly.

9.10.2 About the Chart

The fluid chart (Figure 8 on page 38) visually illus-trates some of the important qualities of the fluidsshown.

Temperature Range: The temperature scale is shownin degrees Celsius. The fluids’ general range of appli-cation is indicated by the shaded bands. Qualities in-cluding pour point, freeze point, important viscositypoints, flash point, boiling point and others may beshown.

Freezing Point: The freezing point of a fluid is an obvi-ous limitation to stirring. As the freezing point is ap-proached high viscosity may also limit performance.

Pour Point: This represents a handling limit for thefluid.

Viscosity: Points shown are at 50 and 10 centistokesviscosity. When viscosity is greater than 50 centi-stokes stirring is very poor and the fluid is unsatisfac-tory for bath applications. Optimum stirring generallyoccurs at 10 centistokes and below.

Fume Point: This is the point at which a fume hood isrecommended. This point is very subjective in natureand is impacted by individual tolerance to differentfumes and smells, how well the bath is covered, thesurface area of the fluid in the bath, the size and venti-lation of the facility where the bath is located and other


39

conditions.We assume the bath is well covered at thispoint. This is also subject to company policy.

Flash Point: This is the point at which ignition may oc-cur.The point shown may be either the open or closedcup flash point. Refer to the flash point discussion inSection.

Boiling Point: At or near the boiling point of the fluidthe temperature stability is difficult to maintain.

Fuming or evaporation is excessive. Large amountsof heater power may be required because of the heatof vaporization.

Decomposition: The temperature may reach a pointat which decomposition of the fluid begins.Further in-creasing the temperature may accelerate decompo-sition to the point of danger or impracticality.


40

10 Troubleshooting

In the event that the user of the 6054 bath encountersdifficulty in operation this section may help to find andsolve the problem. Several possible problem condi-tions are described along with likely causes and solu-tions. If a problem arises please read this sectioncarefully and attempt to understand and solve theproblem. If the bath seems faulty or the problem can-not otherwise be solved, then contact the factory forassistance.

10.1 The Heater Indicator LED Stays

Red But The Temperature Does

Not Increase.

Here the display does not show “cut-out” nor displaysan incorrect bath temperature, but the controller oth-erwise appears to operate normally. The problemmay be either insufficient heating or no heating at all.Insufficient heating may be caused by the heaterpower setting being too low, especially at higher oper-ating temperatures. Switching to a higher heaterpower switch setting may solve the problem. If one ormore of the heaters are burned out, it also may causethis problem. If this seems the case contact the fac-tory for assistance.

If the heater seems not to be receiving power at all,then first check the heater fuse. If the fuse is burnedout, then try replacing the fuse with a new one (of thesame rating) and then check to see if the bath re-sumes normal operation. If the fuse blows gain thenthere may be a shorted heater. Contact the factory. Ifthe fuse was not blown in the first place then the prob-lem may be a faulty solid-state relay or mechanical re-lay. Contact the factory for assistance.

10.2 The Controller Display Flashes

“CUT-OUT” And The Heater

Does Not Operate.

The display will flash “CUT-OUT” alternately with theprocess temperature. If the process temperature dis-played seems grossly in error then also consult Sec-tion 6.8 after this procedure is followed. Normally the

cut-out disconnects power to the heater when thebath temperature exceeds the cut-out set-point. Thiswill cause the temperature to drop back down to asafe value. If the cut-out mode is set to “AUTO” thenthe heater will switch back on when the temperaturedrops. If the mode is set to “RESET” then the heaterwill only come on again when the temperature is re-duced and the cut-out is manually reset by the opera-tor. See Section 6.8. Check that the cut-out set-pointis adjusted to 10 or 20°C above the desired bath oper-ating temperature and that the cut-out mode is set asdesired.

If the cut-out activates when the bath temperature iswell below the cut-out set-point or the cut-out does notreset when the bath temperature drops and it is man-ually reset, then the cut-out circuitry may be faulty orthe cut-out thermocouple sensor may be faulty or dis-connected. Contact the factory for assistance.

10.3 The Display Flashes

“CUT-OUT” And An Incorrect

Process Temperature.

The problem may be that the controller’s voltmeter cir-cuit is not functioning properly. This could be a prob-lem with the memory back-up battery. If the batterypower is insufficient to maintain the memory thendata may become scrambled causing problems. Anearby large static discharge may also affect data inmemory. The memory may be reset by holding the“SET” and “EXIT” keys down while power to the con-troller is switched on. The display will show “—init—”indicating the memory is being initialized. At thispoint, each of the controller parameters and calibra-tion constants must be reprogrammed into memory. Ifthis solves the problem but the same problem reoc-curs then the battery should be replaced. Contact thefactory. If initializing the memory does not remedy theproblem then there may be a failed electronic compo-nent. Contact the factory.

Troubleshooting

41

10.4 The Displayed Process

Temperature Is In Error And

The Controller Remains In The

Cooling Or Heating State At

Any Set-point Value.

Possible causes of this problem may be either a faultycontrol probe or erroneous data in memory. Theprobe may be disconnected, burned out, or shorted.Check that the probe is connected properly. Theprobe may be checked with an ohmmeter to see if it isopen or shorted. The probe is a platinum 4-wire DIN43760 type therefore the resistance should read 0.2to 2.0 ohms between pins 1 and 2 on the probe con-nector and between pins 3 and 4. The resistanceshould read 100 to 300 ohms between pins 1 and 4. Ifthe probe is defective contact the factory.

If the problem is not the probe then it may be causedby erroneous data in memory. Re-initialize the mem-ory as discussed in Section 10.3 above. If the prob-lem remains then it may be caused by a defectiveelectronic component. Contact the factory.

10.5 The Controller Controls Or

Attempts To Control At An

Inaccurate Temperature.

Here the controller operates normally except whenthe controller has reached stable control of the bathtemperature, the temperature does not agree withthat measured with the user’s reference thermometerto within the specified accuracy. This problem may becaused by an actual difference in temperature be-tween the points where the control probe and ther-mometer probe measure temperature or byerroneous bath calibration parameters or a damagedcontrol probe.

Check that the bath has an adequate amount of fluidin the tank and that the pump is operating causingfluid to circulate completely. Check that the thermom-eter probe and control probe are both fully insertedinto the bath to minimize temperature gradient errors.

Check that the calibration parameters are all correctaccording to the certification sheet. If not then repro-

gram the constants. It may be that the memorybackup battery is weak causing errors in data as de-scribed in Section 10.3.

Check that the control probe has not been struck,bent, or damaged. If the cause of the problem remainsunknown then contact the factory.

10.6 The Controller Shows That The

Output Power Is Steady But

The Process Temperature Is

Unstable.

If the bath temperature does not achieve the expecteddegree of stability when measured using a thermom-eter, try adjusting the proportional band to a narrowerwidth as discussed in Section 6.7.

10.7 The Controller Alternately

Heats For A While Then Cools.

This is typically oscillation caused by the proportionalband being too narrow. Increase the width of the pro-portional band until the temperature stabilizes as dis-cussed in Section 6.7.

10.8 The Controller Erratically Heats

Then Cools, Control Is

Unstable.

If both the bath temperature and output power do notvary periodically but in a very erratic manner, then theproblem may be excess noise in the system. Noisedue to the control sensor should be less than0.001°C. However, if the probe has been damaged orhas developed an intermittent short, then this maycause erratic behavior.Check for a damaged probe orpoor connection between the probe and bath. Inter-mittent shorts in the heater or controller electronic cir-cuitry may also be a possible cause. Contact thefactory if this seems to be the case.

Troubleshooting

42

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