instruction model ph150 ph and orp converter manual · for the health and safety of our employees....
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IM 12B6B4-E-H 2nd edition
InstructionManual
YOKOGAWA
Model PH150pH and ORP Converter
IM 12B6B4-E-H
TABLE OF CONTENTS
PREFACE
1.INTRODUCTION AND GENERAL DESCRIPTION ........................................................1
1-1. Instrument Check.................................................................................................11-2. Application ...........................................................................................................2
2. GENERAL SPECIFICATIONS........................................................................................3
3. INSTALLATION AND WIRING.......................................................................................4
3-1. Installation Site .....................................................................................................43-2. Mounting and Dimensions....................................................................................43-3. Preparation ..........................................................................................................63-4. Cables, Terminals and Safety Cover.....................................................................63-5. Wiring the Power Supply ......................................................................................73-6. Wiring the Relay Contacts ....................................................................................73-7. Wiring the Current Outputs ..................................................................................83-8. Wiring the Sensors ..............................................................................................9
4. OPERATION OF EXAxt PH150 ...................................................................................11
4-1. Main Display Functions ......................................................................................114-2. Trending Graphics..............................................................................................114-3. Zoom in on Details .............................................................................................114-4. Information Function...........................................................................................134-5. Secondary-Primary Value Display Switch ...........................................................134-6. Setup-Calibration and Commissioning ...............................................................134-7. Matrix Interpolation.............................................................................................14
5. MENU STRUCTURE COMMISSIONING ....................................................................15
5-1. Sensor Setput ....................................................................................................165.2. Temperature Settings... ......................................................................................165.3. Temperature Compensation ...............................................................................165-4. Calibration Settings ............................................................................................185-5. Impedance Settings ...........................................................................................185-6. mA Output Setput..............................................................................................205-7. Contact Output Setput.......................................................................................225-8. Configure Hold... ................................................................................................225-9. Error Configuration .............................................................................................245-10. Logbook Configuration .......................................................................................245-11. Advanced Setup.................................................................................................265-12. Display Setup .....................................................................................................28
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6. QUICK SETUP FOR THE EXAxt PH150.....................................................................30
7. CALIBRATION..............................................................................................................31
7-1. General ..............................................................................................................317-2. Manual Calibration..............................................................................................317-3. Automatic Calibration .........................................................................................317-4. Sample Calibration .............................................................................................317-5. Temperature Calibration .....................................................................................327-6. ORP & rH Calibration .........................................................................................327-7. Operation of HOLD during Calibration ................................................................327-8. ITP Calibration....................................................................................................32
8. MAINTENANCE ...........................................................................................................34
8-1. Periodic Maintenance ........................................................................................348-2. Periodic Maintenance for the Sensor..................................................................34
9. TROUBLESHOOTING..................................................................................................36
9-1. General ..............................................................................................................369-2. Calibration Check...............................................................................................369-3. Predictive Maintenance ......................................................................................369-4. Poor Calibration Technique ................................................................................369-5. Error Display and Actions ...................................................................................36
10. SPARE PARTS ...........................................................................................................37
APPENDICES ...................................................................................................................38
Appendix 1 : Temperature Compensation ...................................................................38Appendix 2 : Buffer Tables...........................................................................................40
Quality Inspection Standard ..........................................................................................41Quality Inspection Certificate .......................................................................................47
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PREFACE
Electric dischargeThe EXAxt analyser contains devices that can be damaged by electrostatic discharge. Whenservicing this equipment, please observe proper procedures to prevent such damage.Replacement components should be shipped in conductive packaging. Repair work shouldbe done at grounded workstations using grounded soldering irons and wrist straps to avoidelectrostatic discharge.
Installation and wiringThe EXAxt analyser should only be used with equipment that meets the relevant IEC,American or Canadian standards. Yokogawa accepts no responsibility for the misuse of thisunit.
CAUTION
The Instrument is packed carefully with shock absorbing materials, nevertheless, theinstrument may be damaged or broken if subjected to strong shock, such as if theinstrument is dropped. Handle with care.
Although the instrument has a weatherproof front construction, the transmitter can beharmed if the body becomes wet.Do not use an abrasive or organic solvent in cleaning the instrument.
NoticeContents of this manual are subject to change without notice. Yokogawa is not responsiblefor damage to the instrument, poor performance of the instrument or losses resulting fromsuch, if the problems are caused by: Incorrect operation by the user. Use of the instrument in incorrect applications. Use of the instrument in an inappropriate environment or incorrect utility program. Repair or modification of the related instrument by an engineer not authorised byYokogawa.
Warranty and serviceYokogawa products and parts are guaranteed free from defects in workmanship andmaterial under normal use and service for a period of (typically) 12 months from the date ofshipment from the manufacturer. Individual sales organisations can deviate from the typicalwarranty period, and the conditions of sale relating to the original purchase order should beconsulted. Damage caused by wear and tear, inadequate maintenance, corrosion, or by theeffects of chemical processes are excluded from this warranty coverage.
In the event of warranty claim, the defective goods should be sent (freight paid) to theservice department of the relevant sales organisation for repair or replacement (atYokogawa discretion). The following information must be included in the letteraccompanying the returned goods:
WARNING
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Part number, model code and serial number Original purchase order and date Length of time in service and a description of the process Description of the fault, and the circumstances of failure Process/environmental conditions that may be related to the failure of the device. A statement whether warranty or non-warranty service is requested Complete shipping and billing instructions for return of material, plus the name and
phone number of a contact person who can be reached for further information.
Returned goods that have been in contact with process fluids must bedecontaminated/disinfected before shipment. Goods should carry a certificate to this effect,for the health and safety of our employees. Material safety data sheets should also beincluded for all components of the processes to which the equipment has been exposed.
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1. INTRODUCTION AND GENERAL DESCRIPTIONThe Yokogawa EXAxt PH150 is a 4-wire panel mounted converter designed for industrialprocess monitoring, measurement and control applications. This instruction manual containsthe information needed to install, set up, operate and maintain the unit correctly. Thismanual also includes a basic troubleshooting guide to answer typical user questions.
Yokogawa can not be responsible for the performance of the EXAxt analyzer if theseinstructions are not followed.
1-1. Instrument checkUpon delivery, unpack the instrument carefully and inspect it to ensure that it was notdamaged during shipment. If damage is found, retain the original packing materials(including the outer box) and then immediately notify the carrier and the relevant Yokogawasales office.
Make sure the model number on the textplate affixed to the side of the instrument agreeswith your order. Examples of the text plate is shown below.
Figure 1-1. Textplate
NOTE: The textplate will also contain the serial number and any relevant certification marks.Be sure to apply correct power to the unit, as detailed on the Textplate.
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1-2. ApplicationThe EXAxt converter is intended to be used for continuous on-line measurement of pH &/orORP in industrial installations. The unit combines simple operation and microprocessor-based performance with advanced self-diagnostics and enhanced communicationscapability to meet the most advanced requirements. The measurement can be used as partof an automated process control system. It can also be used to indicate operating limits of aprocess, to monitor product quality, or to function as a controller for a dosing/neutralisationsystem.
Yokogawa designed the EXAxt analyzer to withstand industrial environments. The contoller may only be installed in a panel mounted configuration. The front panel forms an IP65 water tight seal against the flat face of the panel. Integralmounting clamps can be operated from the front of the panel. Sensors should normally be mounted close to the converter in order to ensure easycalibration and peak performance. If the unit must be mounted remotely from the sensors,WF10 extension cable can be used, up to a maximum of 50 meters (150 feet), with a BA10junction box, and up 10 meters standard sensor cable.
The EXAxt is delivered with a general purpose default setting for programmable items (seeChapter 5). While this initial configuration allows easy start-up, the configuration should beadjusted to suit each particular application. An example of an adjustable item is the type oftemperature sensor used. The EXAxt can be adjusted for a number of different types oftemperature sensors.
Details provided in this instruction manual are sufficient to operate the EXAxt with allYokogawa sensor systems and a wide range of third-party commercially available probes.For best results, read this manual in conjunction with the corresponding sensor instructionmanual.
Yokogawa designed and built the EXAxt to meet the CE regulatory standards. The unitmeets or exceeds stringent requirements (see section 2) without compromise, to assure theuser of continued accurate performance in even the most demanding industrial installations.
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2. General specifications of EXAxt PH150A) Inputs specifications
: One high impedance input (≥ 1013Ω). One low impedanceinput (≥ 108Ω). One temperatureinput. One liquid earth input.
B) Input rangespH : -2 to 16 pHORP : -1500 to 1500 mVrH : 0 to 55 rHTemperature : Pt1000, -30 to 140ºC
: Pt100, -30 to 140ºC: 350Ω (DKK), -30 to 140ºC: 5k1, -30 to 140ºC: 6k8, -30 to 140ºC: NTC10k, -20 to 140ºC: NTC 8k55, -10 to 120ºC: 3kBalco, -30 to 140ºC
C) AccuracypH input : ≤ 0.01 pHORP input : ≤ 1 mVTemperature : ≤ 0.3 ºC (≤ 0.4 ºC for Pt100) mA output circuits
: ≤ 0.02 mAAmbient temperature influence
: ± 0.01% /ºCD) Transmission SignalsGeneral : Two isolated outputs of 4-20
mA. DC with common negative.Maximum load 600Ω.
Control function: Linear or 21-step table for pH,
temperature, ORP or rH.PID control.Burn up (21.0mA) or burn down(3.6mA) to signal failure.
E) Contact outputsGeneral : Two SPDT relay contacts with
display indicators.Switch capacity: Maximum values 100 VA,
250 VAC, 5 Amps.Maximum values 50 Watts,250 VDC, 5 Amps.
Status : High/Low process alarms,selected from pH, ORP, rH andtemperature. Configurable delaytime and hysteresis.
Control function: On / Off
PID duty cycle or pulsed frequencycontrol. FAIL alarm
F) Temperature compensationFunction : Automatic or manual.
Compensation to Nernstequation. Process compensation byconfigurable temperaturecoefficient, NEN6411 for strongacids/bases or programmablematrix.
G) Calibration: Semi-automatic 1/2/3 point
calibration using pre-configuredNIST, US, DIN buffer tables 4, 7 & 9,or with user defined buffer tables,with automatic stability check. Manual adjustment to grab sample.
H) Serial Communication: Bi-directional HART digital
communication, superimposedon mA1 (4-20) signal.
I) Logbook : Software record of importantevents and diagnostic datareadily available in the display.
J) Display : Graphical Quarter VGA (320 x240 pixels) LCD with LEDbacklight and touchscreen. Plain(English) language messages,with choice of alternativelanguages.
K) Shipping detailsPackage size w x h x d
: 180 x 161 x 243 mm (7.1 x 6.3 x 9.6 inch)
Package weight : app. 1.1 kg (2.4lbs)L) HousingEnclosure : High quality chemical resistant
plastic front 96x96 mm. SS housing behind the panel depth 98 mm behind the panel (121 mm including cover)
Mounting : Panel-mounted design in a standardDIN-size 92x92 mm cutout.
M) Power supply: 85-265 VAC (47-63 Hz) 10VA max
9.6-30 VDC 10W maxN) Regulatory compianceEMC : Meets directive 89/336/EEC
Emission conform EN 55022 class A Immunity conform IEC 61000-6-2
Low Voltage : Meets directive 73/23/EECConform IEC 61010-1, UL3111-1and CSA 22.2 No. 1010.1,Installation category II, Pollutiondegree 2Certification for cCSAus, Kema Keurand Geprüfte Sicherheit
O) Environment and operational conditionsAmbient temperature
: -20 to +55 ºCStorage temperature
: -30 to +70 ºCHumidity : Up to 90% RH at 40 ºC
(non-condensing)Environmental protection
: IP65 (NEMA 4X) front panel, IP20behind the panel
Data protection : EEPROM for configuration data andlogbook. Lithium cell for clock.
Watchdog timer : Checks microprocessor.Power down : Reset to measurement.Automatic safeguard
: Auto return to measuring modewhen touchscreen is untouchedfor 10 min.
ModelCode
SuffixCode
OptionCode Description
Panel mount pH converter85 - 265 VAC power supply9.6 - 30 VDC power supplySecond language - GermanSecond language - FrenchSecond language - JapaneseSecond language - SpanishAlways AATagnumber
PH150-A-D -D -F -J
-S -AA
/TAG
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3. INSTALLATION AND WIRING
3-1. Installation siteThe EXAxt converter should be installed as close as possible to the sensor to avoid longcable runs between sensor and converter. In any case, the cable length should not exceed60 meters (200 feet). Select an installation site where:
Mechanical vibrations and shocks are negligible No relay/power switches are in the direct environment Access is possible rear of the unit for wiring The transmitter is not mounted in direct sunlight or severe weather conditions Maintenance procedures are possible (avoiding corrosive environments)
The ambient temperature and humidity of the installation environment must be within thelimits of the instrument specifications. (See chapter 2).
3-2. Mounting and dimensions Refer to fig. 3-1 to 3-5. Note that the EXAxt has integrated mounting clamps:The EXAxt uses an Integral mounting clamp at each corner, driven by screws operated fromthe front panel, fig. 3-1. Ensure that the clamp “fingers” are backed off a few millimeters more than the thickness
of the panel, fig. 3-2. Insert the unit through the mounting hole (Square hole, 92 x 92 tol.+0.5/-0mm), fig. 3-3-1. Rotate the unit slightly anti-clockwise to allow the clamp fingers to pass through the panel. Rotate the unit clockwise slightly (back to square) and tighten the 4 screws to hold it in
place, fig. 3-3-2 and fig. 3-3-3. Tighten the screws progressively to ensure that the panel seal seats evenly, fig. 3-3-4.
Fig. 3-1. Integrated mounting clamps Fig. 3-2. Clamp Finger
FINGER
PANEL THICKNESS11 to 18 mm
FINGER
PANEL THICKNESS0 to 11 mm
1
2
2 31 4
Fig. 3-3. Insertion of the Unit through a mounting hole
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Fig. 3-5. Panel mounting cut-out
Fig. 3-4. Housing dimensions and layout
C/L
C / L
100 (3.94") min
Cut-Out92x 92
Tol. +0,5/-0 (3.63" x 3.63"Tol. +0.02/-0)
100
(3.9
4") m
in
96 (3.8")
96
(3
.8")
25 (1
")
90 (3.54")
95.5
(3.7
6")
Safety Cover
118 (4.6")
25 (1") 121 (4.75")
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3-3. PreparationThe power/output connections and the sensor connections should be made in accordancewith the scheme shown in Figure 3-6. The terminals are of a plug in style for ease of wiring.
3-4. Cables, terminals and safety coverThe EXAxt 150 is equipped with terminals suitable for the connection of finished cables inthe size range: 0.13 to 2.5 mm2 (26 to 14 AWG). Forked or pin crimps can be used toterminate the cables.
Safety Note:When the wiring of the power/contact connections has been completed the clear safetycover should be clipped into place.
Figure 3-6. Rear view showing connection
Caution - Risk of electric shock
Caution - See section 3.7 and 3.8 for correct wiring
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4-20 mA
HART 275HAND HELD
OUTPUTSIGNALS
mA1
mA2
S1
S2
CONTACTOUTPUT
SENSOR
POWER9.6 to 30 VDC, 10W max 85 to 265 VAC, 10VA max
Figure 3-7. System configuration
3-5. Wiring the power supplyMake sure the power supply is switched off. Also, make sure that the power supply iscorrect for the specifications of the EXAxt and that the supply agrees with the voltagespecified on the textplate.Local health and safety regulations may require an external circuit breaker to be installed.The instrument is protected internally by a fuse soldered to the printed circuit board. The fuse rating is dependent on the supply to the instrument.
Fuse ratings are:For the DC version 1 AFor the AC version 125 mA250 Volt, Time-lag T, IEC60127
3-6.Wiring the Relay Contacts Connect the relay contacts having regard to the use to which the relays are put. Thevoltage and current being switched should determine the type of wire used. Because therelays may be used to switch higher voltages, there is a cover for the terminal block (andmains supply terminals) that should be clipped in place when the wiring is completed. Thisis to prevent electric shock to unwary personnel.
Action
Power OFF
Power ONAlarm OFF
Power ONAlarm ON
S1, S2 FAIL
NC
NC
NO
NC
NC
NO
common
NC
NO
LED
3-8. Normally open and normally closed
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Connection Diagram
High Voltage Signal
mA OutputsPowerSupply
RelayContacts
Sensor Inputs
POWER SUPPLY OUTPUTS
100-240VAC/10VA
CONTACTS
INPUTS
SEE MANUAL
NC
C
NO
NC
C
NO
S1
S2
240V/5A AC/DC 100VA/50W Shield
LE
Shield
pH
Ref
Temp
mA1
mA2
Shield
HIGH VOLTAGE
L
N
1
2
3
31
32
33 +-
11
12
13
17
14
15
16
+-
+-
61
62
65
66
63
41
42
43
Figure 3-9. Connection diagram
3-7. Wiring the Current Outputs
The current outputs should be connected using shielded twisted pair signal cable. Thescreen (shield) should be connected to ground (at one end only).
Note: The HART signal is super imposed on mA1. When using this signal, attention shouldbe paid to the load resistance. In some cases a separate load resistor will be needed,across which the HART signal can be read. In this case a 250 Ω resistor should be used.
Caution - Risk of electric shock
Caution - See section 3.7 and 3.8 for correct wiring
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3-8. Wiring of sensorsGenerally, signals from pH sensors are atlow voltage and current level, with a veryhigh source impedance. A lot of care mustbe taken to avoid interference. Beforeconnecting sensor cables to the transmittermake sure that following conditions aremet: – the sensor cables are not mounted in
tracks together with high voltage and/orpower switching cables
– only standard sensor cable or extensioncable is used
– the transmitter is mounted within thedistance of the sensor cables (max. 10m) + up to 50m WF10 extension cable.
– the setup is kept flexible for easymaintenance and retraction of thesensors in the fitting.
Refer to figure 3.10, for sensor wiringdrawings. Refer also to the relevant sensorinstructions.
The EXAxt 150 can be used with a widerange of commercially available sensortypes from Yokogawa and othermanufacturers. The sensor systems fromYokogawa fall into two categories, the onesthat use fixed cables and the ones withseparate cables.
To connect sensors with fixed cables,simply match the terminal numbers in theinstrument with the identification numberson the cable ends.PD20, PF20, PR20 and PS20 fittings andsensors are all in the category of fixedcables.
For separate Yokogawa sensors and theWU20-PC cables follow the scheme offigure 3.10.This also applies to sensors from othersuppliers.
Shield
Temperaturesensor
Referenceelectrode
Liquid earth(Solutionground)
pH glass sensor(or metal ORP Sensor) Shield
Shield
pH/ORP
Figure 3-10. General connections forpH or ORP measurement
3-8-1. Using the EXAxt PH150 withsensor systems without solutionground.
The use of the solution ground enhances themeasurement by removing noise and helpingto avoid earth loops. It is possible to use thePH150 without a solution ground for simpleelectrode systems. An additional disadvan-tage is that this eliminates the referenceimpedance checking diagnostic.The configuration below in used to eliminatethe solution ground. Mind to disable referenceimpedance check in Commissioning>>Commissioning>>Error configuration>> Error 3/3Error configuration>> Error 3/3
Note: This is the simplest configuration. 13& 14 are interconnected and form thereference input. The measuring input is stillon 15. Other cables may provide additionalscreens: refer to the sensor instructions forconnections.
Figure 3-11. General connections forpH or ORP measurement
Shield
Temperaturesensor
Referenceelectrode
pH glass sensor(or metal ORP Sensor) Shield
Shield
pH/ORP
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TEMPERATURE 11
TEMPERATURE 12
REFERENCE 13
METAL (ORP) 14
GLASS (pH) 15
SHIELD 16
17
pH/ORP/rH Wiring
3-12. Sensor wiring diagrams (for pH/ORP/rH measurement)
3-8-2 PH20, FU20 & FU25 sensors for pH/ORP/rH
pH/ORP/rH measurement When using a glass, reference and metal electrode or a 4 in 1 sensor like the PH20, FU20and FU25, one can measure both pH and ORP at the same time. The Platinum electrodedoubles as a liquid earth (solution ground) electrode. Configure the EXAxt PH150 for sensortype “pH & ORP” using Commissioning >> Sensor setup>> pH+ORPCommissioning >> Sensor setup>> pH+ORP
As this sensor combination enables simultaneous measurements, select the process valuesof interest: Commissioning >> Measurement setup>> Main parameter>>Commissioning >> Measurement setup>> Main parameter>>
pH OnlyORP OnlypH + ORPpH + rHrH Only
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4. OPERATION OF EXAxt PH150
4-1. Main display functions
4-2. Trending graphics.
Pressing the button changes the displayinto a graphical mode in which the averagemeasured value is shown on a time scale.The “Live” value is also digitally displayed ina text box. The time scale ( X-axis) and theprimary value scale (Y-axis) are set in the“DISPLAY SETUP” menu. The full screendisplays a trend of 51 points that representthe average of the selected time interval.The analyzer samples the measurementevery second. The trending graphic alsoshows the maximum and minimummeasured value in the that interval. For example if the time scale is set to 4hours, then the trend is shown for 4 hoursprior to the actual measurement. Each pointon the trend line represents the averageover 4*60*60/51 = 282 measurements(seconds).
4-3. Zoom in on details
This button gives access to the diagnosticinformation of the analyzer. The followingmessages will appear under normal(default) conditions:
4-3-1. ZERO = calibrated sensor offset inmV. Theoretically the sensor reads 0 mV ina buffer solution with the same pH value asthe Isopotential pH value of the sensor(default 7.00 pH). The ZERO value indicatesthe condition of the sensor. If the valueexceeds +/- 120 mV ( or user definedlimits) an error message is displayed aftercalibration and the calibration is rejected.The trend of ZERO drift during the lifetimeof the sensor is used to predict the lifetimeof the sensor. ZERO can also be displayed in pH unitsand then it represents the pH value wherethe sensor output is 0 mV at 25 ºC. Go to:Commissioning >> Measurement >>Commissioning >> Measurement >>Calibration Settings >> Zero andCalibration Settings >> Zero andSlope UnitsSlope Units
4-3-2. SLOPE = calibrated efficiency ofthe sensor unit in percentage of theoreticalslope of the sensor unit. The theoreticalslope follows from the NERNST equationand is 59.16. The SLOPE can be calibratedonly after a two-point calibration in buffersolutions with a different pH value. A lowslope indicates that the sensor is not cleanor it indicates a bad sensor. If thecalibrated slope exceeds the range 70-110% ( or user defined limits) then thecalibration is rejected and a error messageis shown.The SLOPE can also be displayed as mV/pHvalue at 25 ºC if the user has defined thisvariable as mV/pH in CommissioningCommissioning>> Measurement >> Calibration>> Measurement >> CalibrationSettings >> Zero and Slope UnitsSettings >> Zero and Slope Units
-Go to graph screen
-Go to detail screen
-Go to info screen
-Go to setup screen
-Home key back to mainscreen-One level up-Scroll choices
-Enter selecteddata or choice
deactivated)
(grey means
Max
imum
Min
imum
Minimum
Maximum
Average
Live
read
ing
9.10 pH
Fig 4-2. Trend Screen
Fig 4-1. Main Display
Fig 4-3. Detail Screen
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4-3-3. ITP= This is the pH value at whichthe sensor has the same mV outputindependent on the process temperature.This value is determined by the sensormanufacturer and it is 7.00 mV for mostsensors based on electrolyte filled pH Glass.This value may change over time and it canbe calibrated by 3-point calibration methodin which the buffer solution that has a pHmuch different from the (expected) ITPvalue is measured at an elevatedtemperature as well. If the manufacturerspecifies an ITP different from 7.00, theuser can program this value in the menu:Commissioning >> measurementCommissioning >> measurementsetup >> calibration settings >>setup >> calibration settings >>zero/slope/ITPzero/slope/ITP ..
4-3-4. SENSOR mV= the output of thesensor unit prior to calibration andtemperature compensation. This value isimportant for trouble shooting.
4-3-5. Reference impedance = theelectrical resistance of the liquid junction.The liquid junction forms the electolyticalcontact between the reference element andthe measuring electrode, so it must be keptclean and filled with conductive electrolyte.Otherwise the measurement will suffer frominstability, drift and measuring errors. Theelectrical impedance is one of the mostimportant diagnostic tools for keeping themeasurement in good condition. If the valueexceeds a user defined limit (1000Ω -1000kΩ) an error message will be displayed.
4-3-6. ACTUAL mA1 = the currentoutput in mA of the first current output,which is defined as mA1. The range andfunction of this mA output can be set inCommissioning >> Output setup>>Commissioning >> Output setup>>mA1mA1
4-3-7. ACTUAL mA2 = the currentoutput in mA of the second current output,which is defined as mA2. The range andfunction of this mA output can be set inCommissioning >> output setput >>Commissioning >> output setput >>mA2mA2
4-3-8. Last calibrated = the date onwhich the last sensor calibration is done.The displayed value of the ZERO is theresult of this calibration. The displayedvalue of Slope is not necessarily calibratedon this date: only if the last calibration was a2-point calibration. It is unlikely that thedisplayed value of the ITP is the result ofthis calibration. A 3-point calibration isdone rarely, since it must be done underwell controlled lab.conditions.
4-3-9. Calibration due = the date whenthe calibration must be done according tothe settings of the maintenance timer. Thisis based on scheduled maintenanceprocedures. The maintenance intervals areset in menu: setup>> Commissio-setup>> Commissio-ning>> measurement setup>> cali-ning>> measurement setup>> cali-bration settings >> limits and timingbration settings >> limits and timing
4-3-10. Projected calibration = the datewhen the predictive maintenance functionexpects that recalibration of the sensor unitis necessary for good measurementaccuracy. The analyzer checks the referenceimpedance every hour. If a clean increase ofreference impedance is observed, the user isnotified when a next calibration should takeplace. Prior to calibration the sensor shouldbe well cleaned and rinsed.
4-3-11. Projected replacement = thedate when the predictive maintenancefunction expects that replacement of thesensor is necessary for good measurementaccuracy. After each calibration the slope,zero and reference impedance are logged.Aging of the sensor can be detected fromthis data. If a negative trend is observed,the user is notified when the sensor shouldbe replaced. Good predictions are onlyachieved with good calibration data. Priorto calibration the sensor should always bewell cleaned and rinsed and the calibrationprocedures strictly observed.
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2x to
down
for
4-5. Secondary- Primary Value displayswitch
Pressing on this text block automaticallyswitches the secondary value to the maindisplay (Large font size).
4-6. Setup-Calibration & Commissioning
By pressing the setup key, you getaccess to the operating system of theanalyzer based on menus and submenus.Browse through the list using the keytill you find the required menu and pressthe key to enter this menu. It is alsopossible to press on the or symbolfound beside the menu item.
4-3-12. Device ID = serial number of theanalyzer
4-3-13. Software revision = the revisionlevel of the software in the instrument
If you contact the local sales/ serviceorganization the ID and software revisioninformation is necessary information.Without that information it is impossible tohelp you. It is also very useful to report allthe information that you find on the zoom-in display.
4-3-14. DD revision = the HART devicerevision
4-4. Information function
In this field an information sign , a warningsign or a fail sign can appear. Pushingthis button, the user gets detailedinformation about the status of the sensoror the instrument if applicable.See troubleshooting (chapter 9) for furtherdetails.
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4-7. Matrix InterpolationTemperature compensation matrix.
1. A minimum number of values is required to make interpolation possible.
The highlighted values markes as are mandatory to enter.
Tref T1 T2 T3 T4 T5
Sol1 S1Tr S1T1 S1T5
Sol2Sol3Sol4Sol5 S5Tr S5T1 S5T5
2. Tref (reference temperature) is defined in the Temperature Compensation menu. If Tref is
between T1 an T5 then the value of Tref needs to be entered as T2 or T3 or T4.
Tref T1 T2 T3 T4 T5
Sol1 S1Tr S1T1 S1T5
Sol2Sol3Sol4Sol5 S5Tr S5T1 S5T5
3. For every SxTx that is entered the following values become mandatory to enter:
SxTr, SxT1, SxT5 and Tx
Tref T1 T2 T3 T4 T5
Sol1 S1Tr S1T1 S1T5
Sol2Sol3 SxTr SxT1 SxTx SxT5
Sol4Sol5 S5Tr S5T1 S5T5
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5. MENU STRUCTURE COMMISSIONING
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5-1. Sensor SetupSensor typeThe sensor connection to the terminals isdetermining the setting of this parameter.Three selections can be made here.
pH: Only pH needs to be measured.The glass electrode is connectedto terminal 15 and the referenceis connected to terminal 13.
ORP: Only ORP needs to be measu-red. The metal is connectedtoterminal 15 and the referenceis connected to terminal 13.Liquidearth is connected toterminal 14. If there is no LEterminal 13 and 14 are shortcut-ted and no sensor diagnosticspossible.
pH+ORP: When pH and ORP should bemeasured simultaneousely theglass electrode is connected toterminal 15 and the reference isconnected to terminal 13. Themetal electrode is connected toterminal 14. In this setup it is alsopossible to mea-sure rH, wherethe glass electrode is used as areference to the metal measuringelectrode. For rH measurementthe reference electrode is not ne-cessary. When left out, terminal13 and 14 are shortcutted.
Note: This setting determines the menustructure thoughout the instrument
5-2. Temperature SettingTemp. ElementSelection of the temperature sensor usedfor compensation. The default selection isthe Pt1000 Ohm sensor, which givesexcellent precision with the two wireconnections used. The other options givethe flexibility to use a very wide range ofother sensors.
UnitCelcius or Fahrenheit temperature scalescan be selected to suit the user’spreference.
5-3. Temperature CompensationTwo types of methods can be used here.Automatic when a temperature element isused. Select one of the Temp. elementsused. The other is a manual set tempera-ture, which represent the temperature ofthe process. The latter is used whentemperature measurement is difficult andtemperatures do not vary much.
Reference TemperatureChoose a temperature to which themeasured pH value must be compensated.Normally 25°C is used, therefore thistemperature is chosen as default value.
Process Temperature Compensation TC In addition to the procedure describedin section 5-2-4 it is possible to adjust thecompensation factor directly. If thecompensation factor of the sample liquid isknown from laboratory experiments or hasbeen previously determined, it can beintroduced here. Adjust the value between–0.1 to 0.1 pH/ºC. In combination with thereference temperature setting a linearcompensation function is obtained, suitablefor all kinds of chemical solutions.Matrix The EXAxt is equipped with amatrix type algorithm for accuratetemperature compensation in variousapplications. Select the range as close aspossible to the actual temperature/pHrange. The EXAxt will compensate byinterpolation and extrapolation.Consequently, there is no need for a 100%coverage. See section 4-7 for matrix interpolation.NEN6411 is standard NEN NORM andapplicable for many applications. It’s used for pH compensation in waterapplications using a glass electrode. Thecalculation is valid for all strong acids andstrong bases. The main application is indemiwater and boiler feedwater/condensate.
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These selections will influencea number of choices anddefaults throughout thewhole menu.
In the selection boxesdefaults are shownwith a black background.
Generally defaults areshown with their rangesand possible choices.
+
-30....140
-0.1....0.1
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5-4. Calibration SettingsGeneralCalibration settings for a pH analyzer involveslope (sensitivity), zero (aspot) and ITP(isothermal point). The following figure showsthe pH value to the mV output of the sensor.Characteristic for pH measurement is anoffset also known as aspot [mV] or zero [pH]and a Slope [mV/pH]. For an ideal sensorthe theoretical slope is 59.16 mV/pH at 25ºC.Slope can be entered in mV/pH or a percen-tage of the theoretical slope (100% corres-ponds to 59.16 mV/pH). ITP is where theoutput of the sensor does not change withtemperature. Note that slope and zero aredefined at 25ºC.
UnitsZero(aspot) unitZero is an alternative to Asymmetry Potential.This method conforms to the DIN standardfor instruments IEC 60146-2. Zero isdefined in pH or mV.
Slope (sensitivity) unitSlope can be defined in mV/pH or definedas percentage of theoretical slope at 25ºC.
Limits and timingZero (aspot) High, LowDuring calibration the new zero is checkedfor exceeding these low and high limits.Narrowing the band will prevent bad cali-brations procedures and calibration of badsensors, which results in higher accuracy.The default values should be adjusted tosuit the application and the “users” criterion.
Slope (sensitivity) High, LowDuring calibration the new slope is checkedfor exceeding these low and high limits.Narrowing the band will prevent bad cali-brations procedures and calibration of badsensors, which results in higher accuracy.The default values should be adjusted tosuit the application and the “users” criterion.
Stabilisation timeDuring calibration, the value should bestable within 0.01 pH over this stabilisationtime period. When the pH value is not stablewithin 10 minutes, calibration is aborted.
calibration IntervalThe interval in which a new calibrationmust take place. If the interval is exceededthe instrument will give a warning or a fail(user definable in error configuration 2/3)
BuffersCalibration is done using standardcalibration buffers. Our preference goes toNIST buffers for highest accuracy, but theuser is free to select US, DIN or define hisown. The standard buffers can be found inAppendix A.
Zero (aspot)/Slope (sensitivity)/ITPZero (aspot), Slope (sensitivity), ITPvalues can be entered directly in thissection. These data can be provided bythe manufacturer of the probe, or by theusers laboratory etc. They are determinedindependently of the measuring loop. Alsosee 4-3-1, 4-3-2 and 4-3-3.
NOTE: it is not necessary to enter this datain most cases as the EXAxt automaticallydoes this while performing a calibration.The feature is used in the case of specialelectrode systems and where calibration inthe process environment is not possible.
5-5. Impedance settingReference impedance High, Low The EXAxt has an impedance check, capableof monitoring the impedance of all sorts ofsensor systems. In order to “fine tune” thisdiagnostic tool it is necessary to set it upto match the sensors used.
The system is set to measure highimpedances on input 15 (the one normallyused for the pH glass sensor input) andlow impedances on input 13 (the onenormally used for the reference input).
In applications that have a tendency toleave deposits on the electrodes and toclog the reference sensor junction there isthe possibility to use the impedance check(set error configuration) on the referencesensor to initiate an alarm when one of thelimits is exceeded.
pH
mV
ITP
As pot
0 mV
mV
500
0
- 20014
pHITP0 7
Fig 5-1. Calibration parameters
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Low limit 1.000 kΩ
%
1...1000 kΩ
1...1000 kΩ
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5-6. mA Output SetupGeneralThe general procedure is to define thefunction (control, output, Simulate, off) ofthe output and the process parameterconnected to the output first.Available process parameters depend onselected sensor type and measurementsetup.
mA1/mA2Off : When an output is set off the
output is not used and willgive an output of 4 mA
Control : A selection of P- PI- or PID control
Direction: : ReverseIf the Process variableincreases to the Setpoint(Process variable too high)the output of the controller isdecreased (reverse action).
: DirectIf the Process variableincreases to the Setpoint(Process variable too high)the output of the controller isincreased (direct action).
Output : Linear or table outputSimulated : Percentage of output span:
normal span of outputs are limited from 3.8 to 20.5 mA
Burn set Low or High will give an output of3.6 resp. 21 mA in case of Fail situation.
100%
0%set
pointprocess
value
Direct
100%
0%set
pointprocess
value
Reverse
Fig 5-2. Direct/Reverse action
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0.000100.0
7.00 pH1.00 pH
7.00 pH1.00 pH
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100
50
0
0.3 s
90% 10%
100
50
0
ont toff
90%10%
50% 50%
5-7. Contact Output SetputS1/S2Each Switch (contact) has 4 functions.When a Switch is set to off the Switch isnot used.
Control: A selection of P- PI- or PID control
Alarm: Low or high value Limits monitoring
Hold: A hold contact is energised whenthe instrument is in HOLD
Fail: A Fail contact is energized whena fail situation occurs. Fail situations are configured insection 5-9. For SOFT Fails thecontact and the display LED arepulsating. For HARD Fails thecontact and the display LED areenergized continuously.
The contact reacts to Hard FailsOnly
The contact reacts to Hard andSoft Fails
Simulate: The contact can be switched on/off or a percentage of output can be simulated. This percentageis a analogue value and representsthe on time per second.
5-8. Configure HoldGeneralHold is the procedure to set the outputs toa known state when going into commissio-ning. During commissioning HOLD isalways enabled, outputs will have a fixed orlast value. During calibration the sameHOLD function applies. For calibration, it isup to the user if HOLD is enabled or not.
Note! When leaving Commissioning, Holdremains active until switched off manually.This is to avoid inappropriate actions whilesetting up the measurement
Fig. 5-4. Duty cycle control
pH
% of output range
% duty cycle control
SetpointProportional
range Time
Duty cycle
Fig. 5-5. Pulse frequency control
pH% of output rangeSetpoint
Proportionalrange Time
Maximum pulse frequency
50 % pulse frequency
No pulses
% controller output
t (sec)
LED off
Hys.
Setpoint
LED on
Delay time Delay time
LED off
pH
Fig. 5-3. Alarm contact
Hard Fail Only
Hard + Soft Fail
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alarm
A Soft Fail enables the fail contact pulseA Soft Fail is shown on the display only
7.00 pH1.00 pH
7.00 pH1.00 pH
7.00 pH
0.10pH
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5-9. Error ConfigurationErrors 1/3 ~ 3/3Error message configuration. Two differenttypes of failure mode can be set.
Hard fail gives a steady FAIL flag in thedisplay, and a continuous contact closure.All the other contacts (controls) areinhibited and a Fail signal is transmitted onthe outputs when enabled.
Soft fail gives a flashing FAIL flag in thedisplay, and the relay contact is pulsed.The other contact (controls) is stillfunctional, and the controller continues towork normally. A good example is a controltime-out for a soft fail. A warning that theregular maintenance is due, should not beused to shut down the wholemeasurement.
5-10. Logbook ConfigurationGeneralLogbook is available to keep an electronicrecord of events such as error messages,calibrations and programmed datachanges. By reference to this log, userscan for instance easily determinemaintenance or replacement schedules.
In configure Logbook the user can selecteach item he is interested in to be loggedwhen the event occurs. This can be donefor three separate logbooks. Each logbookcan be erased individually.
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5-11. Advanced setup
DefaultsThe functionality of the EXAxt allows tosave and load defaults to come to a knowninstrument setting. The EXAxt has bothfactory and user defined defaults.After a “load default” the instrument willreset. The following parameters are not includedin a reset:
1. X-axis timing2. Auto return (10 min / disabled)3. Tag4. passwords5. date and time6. language7. the contents of all logbooks8. HART parameters (address, tag,
descriptor, message)
TagA tag provides a symbolic reference to theinstrument and is defined to be uniquethroughout the control system at one plantsite.
PasswordsCalibration and Commissioning may beseparately protected by a password.Default both passwords are empty.Entering an empty password results indisabling the password check.A password can contain up to 8characters.
Date/timeThe Logbooks and trend graph use theclock/calendar as reference. The currentdate and time is set here. The current timeis displayed in the “zoom” menu.
Note! The fixed format is YYYY/MM/DDHH:MM:SS
Test QICThis menu enables the customer toexecute the Quality Inspection test asdescribed in the QIS (attached in this IM).
HARTThe address of the EXAxt in a HARTnetwork can be set. Valid addresses are0...15.
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mV
No action
After the defaults are loaded, the instrument will reset
Load factory defaultsSave current as user definedLoad user defined defaults
No action
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5-12. Display SetupMain DisplayThe main display consists of three lineswith Process Values. Each line is userdefinable with the restriction that each lineshould have a different Process Value. Thedefault settings can be defined here. Bypressing one of the two smaller processvalues, this will become the main processvalue in the main screen. Autoreturn willcause the main display to go to defaultsetting.See also 4.5 Secondary to Primary Valuedisplay Switch.
Note! Configuration possibilities in the mainand secondary display lines are determinedby the choices made in the menu items 8 Measurement setup >> MainMeasurement setup >> Mainparameter andparameter and >> Measurement>> Measurementsetup >> Configure sensorsetup >> Configure sensor
Additional textEach process value can be given anadditional text containing up to 12characters per text. This text is displayedon the main display next to the processvalue. This way the user can distinguishseparate measurements.
X-axis TimingThe time range of the trend graph can beset from 15 minutes up to 1 day.
Y-axis LimitsThe ranges for each measurement need tobe set according the application.
Auto ReturnWhen Auto return is enabled, the converterreverts to the measuring mode (maindisplay) from anywhere in the configurationmenus, when no button is pressed duringthe set time interval of 10 minutes.
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Time Span (x) = 1 hour
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G) S1 default is a High alarm with setpoint 16 pH S2 default is Fail alarm as a fault signalTo change contact output settings followthe routing Commissioning >> Output setup >>Commissioning >> Output setup >>S 1 (& S 2 if needed).
The display/configuration interface isdesigned to be simple and intuitive to use,however, full instructions are to be found insections 4 & 5 of this manual.
6. QUICK SETUP FOR THE EXAxt PH150
A) Check power supply voltage on theinstrument side label
DC 9.6 -30 VoltsAC 85 - 265
B) Make appropriate connections to powersupply, but do NOT switch on.
C) Connect the sensor in accordance withits instructions, and the wiring diagramfound in section 3, in this manual.
D) The unit can now be powered and themeasuring function tested if so desired, orthe connections for current output andrelay contacts can be made, and thecommissioning completed as a single task.
E) The temperature sensor is set as aPT1000 by default. If the sensor hasanother temperature compensator, selectthis by pressing on the “Setup” buttonand followingCommissioning >> MeasurementCommissioning >> Measurementsetup >> Temperature setting >> setup >> Temperature setting >> In this screen you will see
Temperature element Pt1000Unit °C
Touch the PT1000 box or the keywhen PT1000 is selected, and a dropdown menu will appear.
Pt1000Pt1005k13kBalco8k55350NTC10k6k8
The correct temperature sensor can nowbe selected by simply touching it, or using the scroll and enter keys.
F) mA 1 default is a linear 4-20 mAoutput, ranged -2 to 16 pHmA 2 default is a linear 4-20 mA output,ranged 0-100°CTo change current output settings followthe routing Commissioning >> OutputCommissioning >> Outputsetup >>setup >> mA 1 (& mA 2 if needed).
7. Calibration
7-1. Calibration check with buffersolutions.The following tips will help to produce agood calibration.
1. Before starting a calibration, make surethe electrode system is properly cleaned sothat the electrodes are fully functional. Theymust then be rinsed with clean water toavoid contamination of the calibrationsolution.2. Always use fresh buffer solutions toavoid the possibility of introducing errorsfrom contaminated or old solutions. Bufferssupplied as liquids have a limited shelf life,especially alkaline buffers, which absorbCO2 from the air.3. Yokogawa strongly recommends NIST(primary) buffer standards in order toensure the best accuracy and best buffercapacity is available. Commerciallyadjusted buffers (e.g. 7.00, 9.00 or10.00pH) are a compromise as a standard,and are often supplied without thetemperature dependency curve. Theirstability will never be as good as NISTsolutions.
NOTE: NIST (formerly NBS) buffers areavailable as consumable items from anyYokogawa sales office under the followingpart numbers:
6C232 4.01 pH at 25°C6C237 6.87 pH at 25°C6C236 9.18 pH at 25°C
Each packet makes 200 ml of solutionwhen dissolved in good quality distilledwater.
Always ensure that the sensors areproperly conditioned, clean and filled withthe correct electrolyte solution (ifappropriate) before starting a calibration.Refer to section 8 (Maintenance), and tothe sensor instructions for details.
7-2. Manual calibration mode
The unit is adjusted to agree with the valueof a known solution. This may be a buffersolution or a known process sample. Theuser determines the pH value, thetemperature influence and the stability.1- A single point can be set to adjust only
the zero (asymmetry).2- A second point can be set to determine
the slope (sensitivity).3- A third point can be set to determine
the ITP (iso-thermal point). See section ITP calibration Section 4-3-3 and 4-3-8
3-point calibrations require laboratoryconditions.For normal measurement a zero/slopecalibration is the best choice.
7-3. Automatic calibration mode
The PH150 will provide prompts to aid theuser to make a good calibration. High quality buffer solutions must be usedfor best results.The user selects the buffer type that he isusing in the calibration menu.The buffer set is selected inCommissioning>> Measurement>>Commissioning>> Measurement>>Calibration setting>> BuffersCalibration setting>> BuffersSee also Appendix 1.
The PH150 uses internal buffer tables andthe sensor temperature input to determinethe exact calibration values.The EXAxt also determines the stability(drift), and the calibration will be rejectedunless it is within limits.The PH150 records the values internally,and uses them to calculate the finalcalibration.1- A single point can be set to adjust only
the zero (asymmetry).2- A second point can be set to determine
the slope (sensitivity).3- A third point can be set to determine
the ITP (iso-thermal point). See section ITP calibration Section 4-3-3 and 4-3-8
A box contains
5 packets of
powder.
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WARNING
7-4. Sample calibration mode
This mode is used first to record aninstantaneous value for a grab sample. The sample value is held in memory, andnormal measurement and control cancontinue, while the sample is analyzed.Following the analysis re-enter the"Sample" calibration mode. The originalvalue (from memory) is displayed, Therecorded reading is simply adjusted toagree with the analyzed value. The sample mode eliminates thecalculation usually needed for this kind ofcalibration.Only a single (zero) point calibration ispossible in the sample mode.
7-5. Temperature Calibration
In order to make the most measurements,it is important to have a precise temperaturemeasurement. This affects the display oftemperature, and the output signal whenused. More important, however, is thetemperature compensation, and calibrationaccuracy.The temperature of the sensor system shouldbe measured independently with a highprecision thermometer. The display shouldthen adjusted to agree with the reading(zero offset calibration only). For bestaccuracy this should be done as near tothe normal operating temperature as possible.
ORP & rH Calibration Modes
7-6. ORP & rH Calibration
The calibration modes for ORP or rH arethe "Manual" and the "Sample" modes."Manual" calibration can be used for eithersingle or 2 two point calibrations. "Sample" calibration is only a single pointas it is with in pH measurement.Temperature calibration is the same in allmodes, where a temperature sensor isused.
Note: The non-availability of well definedbuffer solutions for ORP and rH eliminatesthe automatic calibration option.
7-7. Operation of Hold Function DuringCalibration
EXAxt PH150 has a HOLD function that willsuspend the operation of the control/alarmrelays and mA outputs.
During calibration, the user may choose toenable HOLD so that the output signals areconstant. Some users will choose to leavethe outputs "live" to record the calibrationevent. This has implications forpharmaceutical manufacture, for example,where an independent record ofcalibrations is mandatory.
The route for HOLD setup isCommissioning >> Output setup>>Commissioning >> Output setup>>Configure HoldConfigure Hold
7-8. ITP Calibration.
EXAxt PH150 can be calibrated to acceptdifferent ITP (iso-thermal point) values. TheITP of Yokogawa sensors is pH 7. Othersensors can have other values, and indeed,this value can change somewhat as thesensor ages. To take account of thedifferences, an ITP calibration is provided.
Fig 8-1.
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It works as follows:-A standard 2-point calibration is performedto determine zero and slope. The twopoints obtained determine line (1) in Fig 8.1A third point is then calibrated with thebuffer furthest from the ITP at hightemperature. This is combined with theknown relationship of slope withtemperature to give line (2) in Fig 8.1Sufficient information is now known for theEXAxt to calculate the precise ITP, which isat the intersection of lines (1) & (2) in Fig8.1
Notes: ITP calibration is only appropriatewhen exceptional accuracy is needed fromthe measurement, or where the sensor hasan ITP deviating from the nominal 7 pH.In most cases it is sufficient to use anominal setting. The value for sensorssupplied by Yokogawa is pH 7 unlessotherwise specified.
33
8-2. Periodic Maintenance of the Sensor
NOTE:Maintenance advice listed here isintentionally general in nature. Sensormaintenance is highly application specific.
To perform correctly, pH sensors should beclean. This may be an obvious statement,but it has some implications for routinemaintenance. The user should consider thereason behind a drift seen in a pH sensorsystem, rather than to blindly recalibratefrequently, and hope to thus minimize theerrors. Most drift in pH systems can betraced to fouling or deposits of some sortbuilding up on the sensor. It is often thecase that a simple frequent cleaning regimecan replace a (too) frequent calibration withthe associated saving in labor and costlycalibration solutions.Neutralization processes where lime or sodais used to raise the pH are well known forcausing coatings and blocking referencejunctions with the insoluble hydroxides thatare precipitated. In such an application, dailywashing of the sensors in a dilute acid willyield a far better performance than a dailybuffer calibration. It will also take a fractionof the time.
Each application should be judged on it'sown merits, some will have greasy depositsthat will need a soapy solution to clean, somemay even require organic solvents to removeresinous deposits. In any case, avoid harshchemicals like concentrated acids and abra-sive cleaners as these will destroy theconditioning of the sensors, and will requirea re-hydration period before full function isrestored. After cleaning the sensors, andprior to a calibration, always rinse thoroughlyin distilled water to ensure that there is noresidue of the cleaning medium to contami-nate your calibration solution.
Notes: Some applications will poison simple sensorswith non-reversible chemical changes. Thesesystems do not improve with cleaning. If yoususpect that your system is one of these,contact your local Yokogawa sales office orrepresentative for advice. An alternativesensor type will improve the performance.
8. MAINTENANCE
8 -1. Periodic Maintenance DisplayThe front of the unit is sealed to IP65(NEMA 4X). In normal operation EXAxt willbe sealed to the flat panel front, with a builtin gasket. Behind the panel, the unit has anIP20 rating.The converter requires very little periodicmaintenance, except to make sure the frontwindow is kept clean in order to permit a clearview of the display and allow proper operationof the touchscreen. If the window becomessoiled, clean it using a soft damp cloth orsoft tissue. To deal with more stubbornstains, a neutral detergent may be used.
NOTES:Never use harsh chemicals or solvents. Inthe event that the window does becomeheavily stained or scratched, refer to theparts list (Chapter 10) for replacement partnumbers.
The nature of the EXAxt PH150 is that thepanel environment should protect the backof the instrument. Exposure of this part ofthe unit to moisture may result in problems.This is especially true because of the highimpedance sensors that the pH measurementuses. This should be borne in mind whenworking behind the panel.
BatteryThe EXAxt analyzer contains a logbookfeature that uses a clock to provide thetimings. The instrument contains a lithiumcell (battery) to support the clock functionwhen the power is switched off. The cellhas an expected working life of 10 years.Should this cell need to be replaced,contact your nearest Yokogawa servicecenter for spare parts and instructions.
FuseThere is a circuit board mounted fuseprotecting the instrument. If you suspectthat this needs to be replaced, contactyour nearest Yokogawa service center forspare parts and instructions
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Where a refillable (flowing electrolyte)reference system is employed, make surethat the reservoir is kept topped up. Therate of electrolyte consumption will againbe process dependent, so experience willshow how often you must refill. Pressurizedsystems need to be regularly checked toensure that the pressure is adequate.
Periodic re-calibration of the sensor systemis necessary to ensure best accuracy. Thistakes into account the aging of thesensors, and the non-recoverable changesthat take place. These processes are slow,however. If frequent re-calibration is needed,it is usually because the cleaning techniqueis not effective, the calibration is not wellexecuted or the pH readings are temperaturedependent. Monthly calibrations should besufficient for most applications.
If a film remains on the pH sensor aftercleaning, or if the reference junction ispartly plugged, measuring errors can beinterpreted as a need for re-calibration.Because these changes are reversible withcorrect cleaning, or adjustment of theelectrolyte flow through the junction, makesure that these items are correct before re-calibrating the system.
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9. TROUBLESHOOTING
9-1. General The EXAxt is a microprocessor-basedanalyzer that performs continuous self-diagnostics to verify that it is workingcorrectly. Error messages resulting fromfaults in the micro-processor systems itselfare monitored. Incorrect programming bythe user will also result in an error, explainedin a message, so that the fault can becorrected according to the limits set in theoperating structure. The EXAxt also checksthe sensor system to establish whether it isstill functioning properly.
In the main display screen is a "StatusInformation" button that will show
For information
For warning - a potential problem isdiagnosed, and the system should bechecked.
For FAIL, when the diagnostics haveconfirmed a problem, and the system mustbe checked.This button gives access to a status reportpage, where "The most applicable error"will be displayed. ("No errors" is displayedduring proper operation)
Explanation>> Description or errormessage and possible remedies
Advanced troubleshooting>> Error codescreen that is used in conjunction with theservice manual. This data will also beneeded in the event that you requestassistance from a Yokogawa servicedepartment.
What follows is a brief outline of the EXAxttroubleshooting procedures includingpossible causes and remedies.
9-2. Calibration checkThe EXAxt PH150 converter incorporates adiagnostic check of the adjusted slope or zerovalue during calibration. If the adjustedvalue stays within 80-120 % of the factoryvalue, it is accepted, otherwise, the unitgenerates an error message, and thecalibration is rejected.
9-3. Predictive MaintenanceEXAxt has a unique prediction feature.Calibration, and reference impedance dataare stored in software data logbooks. Thisdata is then used to calculate a predictionfor maintenance purposes. See section 4-3-10
9-4. Poor calibration techniqueWhen the calibration data is not consistentthis fact is used as a diagnostic tool. Thesignificance of this error message is torequire the user to improve his calibrationtechnique. Typical causes for this error areattempting to calibrate dirty sensors,calibration solution contamination and pooroperator technique.
9-5. Error displays and actionsAll errors are shown in the "Main Display"screen, however, the EXAxt makes adistinction between diagnostic findings.The error messages may be set to OFF,WARN or FAIL. For process conditionswhere a particular diagnostic may not beappropriate, the setting OFF is used. FAILgives a display indication only of that thesystem has a problem and inhibits the relaycontrol action, and can be set to trigger the"Burn" function. "Burn-up or Burn-down"drives the mA output signal to 21 mA or3.6 mA respectively.
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1
2
3
4
5
Table 10.1 Itemized parts listItem no Description Part No.1 Front cover kit. xx150 (cover, hinge(s) & label) K1547SA2 Terminal kit xx150 (power, input, output & relay contacts) K1547SB3 Terminal protect. cover. xx150 K1547SC4 Panel fixing set ( screws, clamps & washers, 4 each per set) K1547SD5 Panel seal K1547SE
Fig. 10-1. Exploded view
10. SPARE PARTS
38
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APPENDICES
Appendix 2
NEN Temperature compensation Matrix
1.1.1 Water compensation
Using the NEN6411 norm temperature compensation can be calculated and is applicable for many applications.
It’s used for pH compensation in water applications using a glass-electrode. The calculation is valid for all strong
acids and strong bases. The main application is in de-mineralized water and boiler feed water/condensate.
The uncompensated pH value is:
[ ]( )0log 3
+−= HcpHuncomp => [ ] .
3 10pHuncomp
OHc−+ =
where:
[ ] [ ] KwOH.cOHc =−+3
=> [ ] [ ]+− =
OHc
KwOHc
3
The following relation can be derived (at reference-temperature):
( [ ] ) ( [ ] )tempref
KwdOHcdOHc .@3 =−− −+
where:
( ) 0846.615.273017053.015.273
33.447110 −++
+== −
tt
AKwA
t
Where: t, ref-temp = temperature expressed in: oC
The compensated pH value is:
( )10log dpHpH
ref−−= −
formula: 3.1.1.1
where d: = concentration change
for d, the next equation can be solved:
( )2
410
1010
10 .@@
2
@@
tempreftemppH
temppH
pH
temppH KwKwKwKw
d
−−+−+
=−
−−
−
formula: 3.1.2.2
Where:
Kw@temp = f (Temp)
Kw@ref -temp= f (RefTemp)
.......
.
.
.
Appendix 1
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5
5.5
6
6.5
7
7.5
8
8.5
9
9.5
10
5 6 7 8 9
NEN 6411 pH Temperature Relationship for Strong Acids and Bases
pH at Process Temperature
pH
at
Ref
eren
ceT
emp
erat
ure
80 ºC
0 ºC
T = Tref = 25ºC
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Appendix 1
Buffer Tables
NIST
°C 0 5 10 15 20 25 30 35 38 40 45 50 55 60 70 80 90 95
1,68pH 1.668 1.670 1.672 1.675 1.679 1.683 1.688 1.691 1.694 1.700 1.707 1.715 1.723 1.743 1.766 1.792 1.806
4,01pH 4.003 3.999 3.998 3.999 4.002 4.008 4.015 4.024 4.030 4.035 4.047 4.060 4.075 4.091 4.126 4.164 4.205 4.227
6,87pH 6.984 6.951 6.923 6.900 6.881 6.865 6.853 6.844 6.840 6.838 6.834 6.833 6.834 6.836 6.845 6.859 6.877 6.886
9,18pH 9.464 9.395 9.332 9.276 9.225 9.180 9.139 9.102 9.081 9.068 9.038 9.011 8.985 8.962 8.921 8.885 8.850 8.833
DIN 19267 (German buffers) so called: technical buffer solutions
°C 0 10 20 25 30 40 50 60 70 80 90
4,65 pH DIN 4.670 4.660 4.650 4.650 4.650 4.660 4.680 4.700 4.720 4.750 4.790
6,79 pH DIN 6.890 6.840 6.800 6.790 6.780 6.760 6.760 6.760 6.760 6.780 6.800
9,23 pH DIN 9.480 9.370 9.270 9.230 9.180 9.090 9.000 8.920 8.880 8.850 8.820
US technical buffers
°C 0 5 10 15 20 25 30 35 40 45 50 55 60
4,0 pH US 4.000 3.998 3.997 3.998 4.001 4.005 4.001 4.018 4.027 4.038 4.050 4.064 4.080
7,0 pH US 7.120 7.090 7.060 7.040 7.020 7.000 6.990 6.980 6.980 6.978 6.970 6.980 6.980
10,0 pH US 10.317 10.245 10.179 10.118 10.062 10.012 9.966 9.926 9.889 9.856 9.828 9.828 9.828
FREE PROGRAMMABLE (Default Settings based on rounded NIST values).
°C 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
buffer 4 4.000 4.000 4.000 4.000 4.000 4.010 4.020 4.020 4.040 4.050 4.060 4.080 4.090 4.110 4.130 4.150 4.160
buffer 7 6.980 6.950 6.920 6.900 6.880 6.870 6.850 6.840 6.840 6.830 6.830 6.830 6.840 6.840 6.850 6.850 6.860
buffer 9 9.460 9.400 9.330 9.280 9.230 9.180 9.140 9.100 9.070 9.040 9.010 8.990 8.960 8.940 8.920 8.900 8.890
The freely programmable table is populated with a basic set of data to provide a start for the user configuration.
This table is intended for the user to be able to choose his buffer solutions to suit his own preference. The data
concerning the pH temperature characteristic will need to be obtained from the supplier of the buffers.
Note: Yokogawa recommend the use of NIST (primary buffer standards) rather than buffers which have been
adjusted by the addition of acid or alkaline materials to the buffer composition. In this was the customer gets a
recognized standard, as well as the best buffer capacity (the ability to resist pH change with contamination).
Packs of NIST buffer powders are available from all Yokogawa sales offices and representatives. Each pack
contains 5 sachets of powder, each sufficient to make 200 ml of solution when dissolved in good quality distilled
water. The part numbers to order are as follows: -
Pack of 5 sachets buffer powder 4.01 pH at 25°C Part No. 6C232Pack of 5 sachets buffer powder 6.87 pH at 25°C Part No. 6C237Pack of 5 sachets buffer powder 9.18 pH at 25°C Part No. 6C236
Appendix 2
41
QIS 12B6B4-E-H 1st edition
Databankweg 203821 AL AmersfoortThe Netherlands
QualityInspectionStandard
YOKOGAWA
Model PH150pH and ORPConverter
Introduction
The test equipment needed is :
BOX 1 : Resistor decade to simulate the temperature sensor, maximum value100 kΩ, adjustable in steps of 0.1 Ω, minimum accuracy 0.1 %.
mV source : To simulate the pH and ORP voltage, adjustable between –1500 mVup to +1500 mV in steps of 1mV, minimum accuracy 0.1 %.
2 fixed resistors : To simulate the load resistance of the mA-output value: 300 Ω,accuracy 1%.
Multimeter : To measure DC currents up to 30 mA, minimum resolution 0.01mA,(preferably 2) minimum accuracy 0.05 % of reading.
To measure Contact Relays open or close.Sensor cable : PC10 – LH2
Connect the PH150 as shown in the figure below. The decade box (BOX 1) to terminals 11& 12 to simulate the temperature input. Set decade box 1 to simulate 25 ∞C, see tablesbelow for the value for the selected sensor. If this box has an earth connection, connect this to terminal 12.Connect the mV source to the input terminals, + (positive) to 15 with screen to 16, -(negative) to 13 with screen to 17, link terminal 14 to the negative terminal of the mVsource.The output terminals are connected through the 300 Ω load resistor to the mA meter.(Note: current outputs may be measured in turn with the same meter, or simultaneously iftwo meters and load resistors are available).
QIS 12B6B4-E-H
42
1.Introduction
Final testing begins with a visual inspection of the unit to ensure that all the relevant partsare present and correctly fitted. After switching on the power to the unit, 5 minutes shouldbe allowed for warm-up, and to stabilise the instrument completely before takingmeasurements.The Device ID. and Sofware revision are shown on the display after pressing the Zoombutton and two times the Enter button .
2.Safety tests
During the production test procedures, the insulation is tested between terminal 3, thesupply earth, and power terminals 1 and 2. The test used applies the following criteria:AC instruments - 2.1 kV DC, <1 mA, for >1 min.DC instruments - 0.7 kV DC, <1 mA, for >1 min.The outputs are also tested for isolation from earth ≥ 9.5 MΩ.
3. Functional tests
During the production test procedures, the following tests are executed as functional test: Visual check during startup Check for the correct language Voltage and current check Contact relay operation check Input contact operation checkThe checkbox ‘Functional test’ on the QIC form is used for the result of these checks.
The Contact Relay operation check can also be executed separately:- Press Setup button - Go to Commissioning- Go to Advanced setup- Go to Test QIC- Set Key to ‘Factory Mode’- In the ‘Test QIC’ menu, set Contacts to ‘Check’
- In the next menu the simulated value to S1 and S2 (at the same time) is set to On or Off, by setting Command to ‘Next value’.
- Press Back button to return to the ‘Test QIC’ menu.- Set Quit test to ‘Yes’- Press Home button to return to normal operation.
Note: if you do not set Quit test to ‘Yes’, and return by only pressing the Home button, oreven by the Auto Return timer, the Normal operation will not operate properly !
Communication test HARTDuring the production test procedures, the communication via the HART protocol is testedusing specialized equipment.
Date / time testDuring the production test procedures, the clock is set and a check is performed to verifythat it is running.The actual date and time of the instrument is shown on the display after pressing the Zoombutton once.
4. Accuracy Test – pH / ORP Input This test can be executed, independent from the current settings of the instrument.- Press Setup button - Go to Commissioning- Go to Advanced setup- Go to Test QIC- Set Key to ‘Factory Mode’- Set mV Input to ‘Check’
Connect mV-source between #15(+) and #13,14(-), according to the table below and readthe mV value on the LCD.
Input [mV] -1500 -750 -250 -100 0 +100 +250 +750 +1500Display -1500 -750 -250 -100 0 +100 +250 +750 +1500(± 1 mV)
Press Back button to return to the ‘Test QIC’ menu.
During production test procedures also the pH and Reference input accuracy are tested, as
well as the pH accuracy with a 1000 MΩ shielded resistor to simulate Glass Impedance.
5. Accuracy Test – Temperature InputIn the ‘Test QIC’ menu, set Temperature to the temperature element of which you want totest the accuracy.Next vary the settings on BOX 1 as listed below and check the readings on the display.
Press Back button to return to the ‘Test QIC’ menu.
6. Impedance checkDuring production test procedures Glass and ORP(metal) Impedance checks areperformed.
Also the accuracy of the Reference Impedance is tested.
7. Accuracy & Linearity Check mA output circuitsIn the ‘Test QIC’ menu, set mA output to ‘Check’.In the next menu the simulated mA values to mA1 and mA2 (at the same time) can be
selected, by setting Command to ‘Next value’.
QIS 12B6B4-E-H
43
-10ºC 25ºC 75ºC 120ºC TolerancePt1000 960.9 Ω 1097.4 Ω 1290.0 Ω 1460.6 Ω ± 0.3 ºCPt100 96.1 109.7 129.0 146.1 ± 0.45k1 4457.4 5100.0 6018.0 6884.2 ± 0.33kBalco 2538.0 3000.0 3660.0 4254.0 ± 0.38k55 47000.0 8550.0 1263.0 343.0 ± 0.3350 309.0 350.0 408.6 461.4 ± 0.3NTC10k 55298.0 10000.0 1480.1 388.6 ± 0.36k8 5943.2 6800.0 8024.0 9125.6 ± 0.3
QIS 12B6B4-E-H
44
During production test procedures the also the ripple at 12.0 mA is tested and the mA-valueat 22.0 mA, with a 600 Ω resistor instead of the normal 300 Ω.
- Press Back button to return to the ‘Test QIC’ menu.- Set Quit test to ‘Yes’- Press Home button to return to normal operation.
Note: If you do not set Quit test to ‘Yes’, and return by only pressing the Home button, or even bythe Auto Return timer, the Normal operation will not operate properly !
8. Overall Accuracy TestThe overall accuracy test is executed in normal operation mode, but it requires a number ofsettings to be modified. It is recommended that the current instrument settings are recordedbefore this overall accuracy test is executed.The required settings are (see IM how to change):- sensor type = pH- temp. element = Pt1000- temp. comp. = None- mA1:
- process parameter = pH- output – linear- 0% value = 0 pH- 100% value = 14 pH
- mA2:- process parameter = temperature- output – linear- 0% value = 0ºC- 100% value = 100ºC
- S1:- process parameter = pH- alarm- setpoint = 7 pH- direction = high
- S2:- fail
Set BOX1 and the mV-source to the values in the table below.Read the pH and Temperature values on the Display. Measure the Actual mA-values andContact settings using the multimeter(s).
Simulated Output Tolerance mA 4.00 mA ± 0.02 8.00 ± 0.02 12.00 ± 0.02 16.00 ± 0.02 20.00 ± 0.02 22.00 ± 0.02
QIS 12B6B4-E-H
45
PH mA1 S1mV Reading Toler. Actual Toler.
[pH] [pH] [mA] [mA]414.4 0 ± 0.05 4.00 ± 0.08 open0 7.00 ± 0.05 12.00 ± 0.08 n.a.-414.4 14.00 ± 0.05 20.00 ± 0.08 closed
Temperature mA2 S2Resistance [Ω] Reading Toler. Actual Toler
[ºC] [ºC]. [mA] [mA]1000.0 0 ± 0.4 4.00 ± 0.08 open1194.0 50.0 ± 0.4 12.00 ± 0.08 open1385.0 100.0 ± 0.4 20.00 ± 0.08 open3000.0 - 0 20.50 ± 0.02 pulse
The tolerances specified relate to the performance of the PH150 in the controlledenvironment of the testing facility. Production testing is carried out in combination with aspecially calibrated automatic test equipment (ATE). In the field, the accuracy and linearityof the test equipment affects the error in the reading. As much as an additional 0.1 mA maybe seen in the mA ouput readings.
Note:The testing of the PH150 is carried out under controlled environmental conditions. The enduser may well find that his ambient conditions varies considerably from the ones noted inthis certificate. In this case it is neces-sary to refer to the General Specification sheet for thedetails of ambient temperature, drift, etc.
QIS 12B6B4-E-H
46
QIC 12B6B4-E-H 1st edition
Databankweg 203821 AL AmersfoortThe Netherlands
QualityInspectionCertificate
YOKOGAWA
Model PH150pH and ORP Converter
47
IM 12B6B4-E-H 02-105 (A) QSubject to change without notice Printed in The NetherlandsCopyright ©
UNITED STATES OFAMERICAYokogawa Corporation ofAmerica2 Dart RoadNEWNAN, GA 30265-1040Tel. +1-770-253 70 00Fax +1-770-251 28 00
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