GLOBAL ELECTRONICS 3-5-331, NARAYANGUDA, HYDERABAD - 500 029 . INDIA .

PHONE No. 2322 6687, 2322 1391FAX: 2322 2484E-mail: info@ge-india.com

INSTRUCTION MANUAL

FOR

DIGITAL

pH CONTROLLER

DPH 503

Dear Customer,

Thank you for purchasing Global Digtal pH Controller DPH 503.

Please read this manually carefully to get the best performance from thisinstrument, especially the section on use and maintenance of sensors.

We take every care at our manufacturing facility to ensure that a qualityproduct reaches our clients. in case you have a problem, please contact ourService and Support department on 040 - 2326 0406 for assistance.

KIndly send us the Warranty card duly filled within fifteen days from the dateof purchase.

GLOBAL ELECTRONICS

The DPH 503 is a pH Control System specially designed for pH control in batchneutralising systems.

Any pH electrode has an inherent lag in sensing. It takes about 15 seconds for thepH electrode to respond and stabilise. Additionally when a dose of acid or alkali isgiven to the process liquid, the dose chemical takes a certain amount of time to mixand result in a uniform batch pH value. In such cases, if the response of the dosingsystem is immediate with respect to the instantaneous pH value of the liquid, it iscertain to result in overdosing and consequent overshoot of corrected pH value. Foreg. if the pH value LO set point is at 8.85 and the dose is continuously fed until the pHreading crosses 8.85, after mixing, the final pH could well be above 9 or maybe even10 pH depending on the strength of the dose chemical, the titration curve for thisprocess and the system dynamics. Now it will be necessary to add acid to bring thepH value down and this process of alternate dosing will continue for a few cycles atleast. The consequence of this is two fold: (1) The quantity of dose reagentsconsumed will be high leading to higher costs and (2) The quality of the process isdiluted due the excess reagents.

To overcome these problems in high lag pH control systems, we at “Global” haveevolved a unique mark/space dosing system with integrators that not only optimizesthe dosing process but also shows you how much dose has been consumed in abatch. This reduces the cost of dose reagents and monitors the quality of the productgiving the operator a control that was not hither to possible.

INTRODUCTION

SALIENT FEATURES

DISPLAY: pH, mV, Temperature, Time, Date, High and Low Integrators and Batch time

Annunciators for ATC, Alarm, Dose, Timer-on Control-on, High Temperature, Hi and Lo pH.

CONTROL: All the limit values can be entered through the front panel keyboard with userfriendly prompting display.

pH: high and Low limit controls with “Mark/Space” dose control. Controller can be switchedOFF from external switch.

V.High and V.Low limits control for plant protection.

Programmable pH control inhibit on High Temperature violation.

ALARM: High/Low or V.High/V.Low limit violation Alarm – Resettable through “ACK” key.

TEMPERATURE: High Temperature setpoint with dead band to protect the electrode andsuspend pH control if desired.

INTEGRATORS: Two integrators HIGH and LOW that totalize the respective dosedurations in seconds.

CALIBRATION: Automatic calibration using 1 point or 2 point calibration using any twobuffers in any order with Automatic recognition and temperature correction for 4.01, 7.00and 10.00 pH buffers from 0° C to 50° C.

OPTION: Calibration by either single or Two point methods from the Transmitter

DOSING: Automatic Acid and Alkali dosing as set by Mark Space timers and controllimits.Manual dosing when required.

TIMER: One Batch Timer to record the Batch duration.

ELECTRODE WASH: Facility for periodic automatic cleaning of the pH electrode with asolvent jet through programmable duration of solvent jet (0 to 99 seconds) and aprogrammable interval between washes (0 to 99 minutes).

SPECIFICATIONS

Display : pH, mV, Temperature, Time, Batch Time, Dose Integrators, Control Stage & Status Annunciators

Input : Combination or Glass Reference pair, PT100, Solution Ground Potential free contact inputs for BATCH, WASH, Control HALT, Liquid level

pH mV Temperature °C

Range : -5 to 19.99 ± 1999 -50 to +200 °CResolution : 0.01 pH 1 mV 0.1°C

Accuracy(Display) : 0.1% ± 1 digit 0.1% ± 1 digit 0.3% ± 1 digit

Drift : < 0.02 pH / 24 hrs @ 2 5 °C (non cumulative)

Input Impedance : > 10 tera Ohm

Input Current : < 1 pA @ 25 °C

Temp. Compensation : Auto or Manual, -30 to + 150°C (RTD PT100)

Programming : Through user friendly keyboard

Control Stages : User definable 1 or 2, Stage 1 user selectable as Time period or Operator input

Control Limits : 6 programmable limits, Hi 1, Hi 2, V.Hi, Lo 1, Lo 2, V.Lo independent for 2 stages Hi Temperature limit and Hysterisis

Control : Dual Mark Space Control with relay outputs for Hi, Lo, V.Hi, V.Lo

Relays rated for 230V AC, 3A resistive,

Programmable High Temperature Control inhibit.

Dose Integrators for Acid and Alkali dosing

Output Analog : 4 to 20mA DC into 600 Ohms, User programmable Span

Calibration : Local or Remote, with Autobuffer or Grab sample, Automatic recognition of 7.00, 4.00 & 10.00 pH buffers with Buffer Temp. correction, Warnings for AP> ± 50 mV, Slope < 90% or > 105%

Electrode Cleaning : User programmable Electrode Cleaning (Wash) with relay output. Programmable wash duration, Post wash wait duration, Time interval between washes. Programmable to wash on Level switch input to clean electrode immediately.

Operating Temperature : -10 to + 45°C

Power Supply : 110 / 230V AC, 45 to 55Hz, 10VA

Dimensions : Wall Mount : 200 x 250 x 150 mm

Flameproof : 250 x 250 x 200 mm

DIGITAL INPUTS

Digital inputs are provided in the controller for the following functions

HALT: This input can be used for a remote ‘HALT CONTROLLER’ command. When the twoterminals marked HALT IN on the back panel are shorted (through a switch) all Control functionsof the DPH 503 are suspended and will remain so as long as the terminals are shorted.

WASH: This input is used to initiate an electrode wash cycle. When the WASH IN terminals areshorted momentarily one Wash cycle as per the programmed WASH ON time (sec) is initiated. Ifthese terminals are kept shorted the WASH cycle will be repeated. During the electrode Washperiod the display shows “Wash XX”, XX being the number of seconds of wash remaining to becompleted for current cycle. After every electrode wash the pH reading is inhibited for 10seconds to allow the electrode to stabilise and during this the display will show “Wait XX”.

DRY: In systems having the optional electrode dry level sensor the Transmitter signals thecontroller through this input that the liquid level is below the electrode bulb. When this happensand remains so for 20 second the instrument shows “El DRY” and all control is suspended.

BATCH: This input is used for Batch processes to Start and Stop control of pH .

Single Stage Operation: In single stage operation, if the switch is pressed, the system startspH control. The CONTROL LED in the front panel lights up, the batch timer and Integrators arereset to zero and the batch number is incremented by one. On pressing this switch again, thecontrol is switched off.

Stage Operation: In two stage systems there are two modes in which the instrument operatesin Stage 1.

STAGE 1 TIME based. In this mode the operation of Stage 1 is time based and the duration ofStage 1 is programmable. On pressing this switch the system starts pH control in stage 1 usingthe data programmed for stage 1. The batch timer is reset to 0 and started. The batch numberis incremented by 1. After the programmed duration of Stage 1, the system automatically goesto pH control of Stage 2 using the data programmed for stage 2. During Stage 2 operation,pressing this switch will stop pH control. The batch timer is also stopped. The indication of pHwill however continue.

STAGE 1 OPERATOR DECIDED:

In this mode the changover from Stage1 to Stage 2 is decided by the operator.

On pressing this switch the system starts pH control in Stage 1 using the data programmed forstage 1. The batch timer is reset to 0 and started. The batch number is incremented by 1. Onpressing this switch during Stage 1 operation the system will automatically go to pH control ofStage 2 using the data programmed for stage 2. During Stage 2 operation, pressing this switchwill stop pH control. The batch timer is also stopped. The indication of pH will howevercontinue.

During Stage 1 the display will show

During Stage 2 the display will show 1P XX.XX

2P XX.XX

pH CONTROL SYSTEM DPH 503

DISP

HIGHYES

INTLO ACKLOW

INTHI

PROGPRT

CAL ESC DOSE

ALARM

NO

RST

CONTROL

HI TEMP

DOSE

TIMER

STATUSATC1P 7.85

SETTING UP the DPH 503 for CONTROL

The DPH 503 has a 7 digit display which displays the pH/mV/Temp and programming data. Italso has 8 LED annunciators to inform the operator of the instrument and process status. Theoperator can program the instrument through a 8 key keyboard. On switching on, theinstrument it does a self check and shows the pH as measured by the electrode withtemperature compensation on Automatic. Before the instrument can be put on line theelectrode calibration and control parameter programming has to be done.

DPH 503 KEYBOARD LAYOUT and FUNCTIONSTHE DPH 503 is a user friendly instrument and requires no special skills to program.Interaction with instrument is done through the 8 key board.

KEY FUNCTIONS

(SELECT DISPLAY MODE): This key allows the user to choose either pH, mV, Temperature, Batchtime, Time or date on the display. On switch on, the instrument will be in pH display mode. The display can be cycled through pH, mV,

Temperature, Batchtime, Time or date using this key.

PRT/CAL: (MAKE A HARD COPY OF THE DATA/CALIBRATE SENSORS) In systems where a printer is connected, pressing this key will cause print out to be generated. Either process data or program data be chosen for a print out. This key is

also used to calibrate electrode or temperature sensor.

PROG/ESC: (PROGRAM THE SYSTEM/RETURN TO pH DISPLAY MODE When in pH display mode, pressing this key once will cause the system to go into programming mode asking the operator for a series of data. Pressing this key

again will cause the programming operation to be terminated. In any mode other than pH valueon display , pressing this key will return the system to pH display mode.

INT HI: 1. INCREMENT THE CURSOR POSITION CHARACTER, 2. START BATCH TIMER, 3. DISPLAY HIGH INTEGRATOR VALUE. This key has three functions. In normal mode of display (pH value), pressing this key

will bring the Hi integrator value on to the display. Pressing PROG key will return the displayback to normal mode. The second function of this key is to start the batch timer. When thebatch time is on display, pressing this key will start the batch timer and “TIMER ON”annunciater on the front panel is lit. In the programming mode the third function of this keycomes into operation. Every time this key is pressed the flashing digit is incremented by one orthe scrolling of the available options for a particular parameter is done.

INT LO: 1. DECREMENT THE CURSOR POSITION CHARACTER, 2. SWITCH OFF BATCH TIMER, 3. DISPLAY LOW INTEGRATOR VALUE) This key also has three functions, During normal mode of display, pressing this key

will bring the LOW integrator value on to the display. Pressing ESC key will return the displayto normal mode. In the programming mode every time this key is pressed the flashing digit ondisplay is decremented by one or scrolling of the available options for a particular parameter isdone. When batch time is on display, pressing this key will stop the batch timer.

DOSE: 1. MANUAL DOSE, 2. CURSOR CONTROL. During normal mode of display this is used to initiate manual dosing. When this key is pressed display shows dose: enquiring about choice of dose (Hi or LOW). To

initiate HI dose press INT HI Key. The display then shows dosehi? Now the operator caninitiate manual HI dose by pressing YES key or abort manual dose by pressing ESC key.

DISP

PRTCAL

PROGESC

INT HI

INTLO

DOSE

YES/ACK: 1. ENTER DATA, 2. ACKNOWLEDGE AND ALARM This key is used to ENTER the data on display and transfer the same to system memory or to give a positive response to a display prompt. If the

operating the alarm is sounded, pressing this key will cause the audio alarm to beswitched off.

RST/NO: 1. RESET INTEGRATOR/BATCH TIMER ON DISPLAY, 2. SET TIME/DATE ON DISPLAY, 3. GIVE A NEGATIVE RESPONSE TO A DISPLAY PROMPT. This key is used to reset the INTEGRATORS AND BATCH TIMER to zero.

When either of the integrators or batch time is on display, pressing this key causes thesystem to display Pressing YES will reset the respective counters. WhenTIME or DATE is on display pressing this key will enable the operator to set TIME or DATEusing, INR, DCR, SHIFT and YES keys. This key can also be used to give a negativeresponse to a display prompt.

CURSOR CONTROL KEYS FOR DATA INPUT:In the Programming mode, when the instrument asks the operator to enter data forControl limits or for dose durations, the 3 cursor control keys are used viz ,Whenever some numerical data input is required, the instrument will show the current datawith 1 digit of the data FLASHING. For eg. if limit LL for Stage 1 is to be changed from07.10 to 05.45, at the prompt the instrument will show ILL 07.10 with the last 0 flashing.The keys will operate ONLY ON THE FLASHING digit, incrementing ordecrementing it by one respectively every time the key is pressed.The key causes the presently flashing digit to freeze and the next digit to flash.

Now if ILL is to be changed from 07.10 to 05.45 at the prompt. the required key sequenceis as below:

Press 5 times to make the display ILL 07.15

Press twice the 7 will now flash

Press twice to make the display ILL 05.15

Press once the 1 will now flash

Press 3 times to make the display ILL 05.45 and Press Ent.

In cases where there is no numerical data to be entered but the operator has to choosefrom preset options the L key is used to change the option for eg. at the ATC ON prompt ifATC off option is required, pressure L will bring ATC OFF on display.

YESACK

RST NO

SURE ?

The DPH503 is provided with two options in the programming mode viz 1. ProgramSetup and 2. Program change and program review.

PROGRAM SETUP: In this mode the operator can set the instrument parameters thatare normally entered only during installation of the instrument .

If a setup is not being done but you want to change the operational parameters press NOat the Setup prompt to go to Program change.

PROGRAM CHANGE: In this mode the operator can set various parameters to suit hisapplication.

PROGRAM REVIEW: To review the program data entered ,Press PGM key followed byDISP key. The program data can be seen using the or keys. Press ESC to end.

PROGRAMMING: Press the PROG key . The system displays

SETUP ?

Only the YES and NO keys are accepted in the setup programming. Press YES toinitiate setup routine. The display now shows ATC ON or OFF depending on the currentsetting. Press YES to retain setting or press NO to change setting. Selection is possibleonly between ATC ON and ATC OFF. When this setting is entered by pressing the YES key,the system responds with Ht on query. If it is desired to inhibit control of the process iftemperature goes above the Hi Temp set limit, select Ht ON , else select Ht OFF.

Now the instrument displays Stg 1

Select Stg 1 for single stage operation or Stg 2 for 2 stage operations.

Now the instrument displays Prt Yes

Select Prt Yes if a printer is connected, or press NO if printer is not used.If Prt Yes is selected ,the instrument displays Prt Al .Press Yes if you need a printout at every limit violation, or press NO if this is notrequired.Now the instrument displays Prt Cal

Press YES if you require a printout of Calibration data after every calibration or pressNO.

Now the instrument displays rem cal/1 pt or rem ca/2pt.

Select rem 1pt if you require Single point Remote calibration , or rem 2pt if 2 pointRemote calibration is required.Now the instrument displays Clean

Press YES if an electrode wash facility is ordered. Press NO otherwise.

If a WASH facility is ordered and Clean YES is entered,the system queries with Clean Dry.Press YES if an electrode dry level sensor is ordered AND it is desired to wash theelectrode automatically upon the liquid level .Now the instrument displays Clean reg.Press YES if automatic electrode washing at regular intervals is required. Press NOotherwise.

This completes the setup and the instrument goes on to the program change routine.

PROGRAMMING

PROGRAM CHANGE: After the setup as described above or on pressing NO to the Setupquery at the beginning the data programming can be done. Here the system respondswith pompts asking for all required data. The data can be changed using the cursorcontrol keys.

If ATC OFF was selected in setup the prompt MTC xxx comes up.

Enter the required MTC value.

The display now shows S1 LIM.Press Yes if you want to change the control limits of Stage 1.

The display now shows 1 LL xx.xx.

Set LL (Very Low) limit of stage 1 and press YES.

The display now shows 1 L 2 xx.xx

Set L2 limit of stage 1 and press YES.

The display now shows 1 L 1 xx.xx

Set L1 limit of stage 1 and press YES.

The display now shows 1H1 xx.xx

Set H1 limit of stage 1 and press YES.

The display now shows 1 H 2 xx.xx

Set H2 limit of stage 1 and press YES.

The display now shows 1 HH xx,xx

Set HH (Very High) limit of stage 1 and press YES.

The display now shows 1H T 040.0

Set High Temperature limit of stage 1 and press YES.

The display now shows 1 D T 005.0

Set high temperature dt of stage 1 and press YES.

If pH control is suspended due to high temperature violation, the control will be resumedwhen the temperature reaches Ht-dt.

The display now shows S1 DOSE.

Press yes if you want to change the dose control timings of Stage 1.The display now shows 1.M.H.A.XXX.Set stage 1 High B mark time and press Yes.The display now shows 1.S.H.A. XXX.Set stage 1 High B space time and press yes

The programming can be terminated at any time by pressing ESC key.

The display now shows 1.M.LA. XXX.Set stage 1 High A mark time and press YesThe display now shows 1.S.L.A. XXX.Set stage 1 High A space time and press YesThe display now shows 1.M.LB.XXX.Set stage 1 Low A mark time and press YesThe display now shows 1.S.L.B. XXX.Set stage 1 low A space time and press Yes.

The display now shows 1.M.L.B.XXX.Set stage 1 low B mark time and press yes.The display now shows 1.S.L.B.XXX.Set stage 1 low B space time and press yes.

If two stage operation was selected all limits, mark/space timings are repeated for stage 2viz.2L2, 2L1 etc.,

If 2 stage operation was selected and the stage 1 operation was set to Time based, then thesystem will now ask Sl xx.

Enter the stage 1 duration in minutes.

The display now shows PRT xx (INTERVAL BETWEEN REGULAR PRINTS).

Set required interval and press YES.

The display now shows dly xx (WAIT AFTER WASH JET IS STOPPED xx sec).

Set wait time and press YES. This wait is given to ensure proper fixing of process solution aftera wash.

The display now shows Cln rt xx.

Enter the duration between automatic electrode washes (in minutes).

The display now shows A L D L Y xx (VIOLATIN DELAY XX sec.).

Set violation time delay using curser control keys and press YES.

When the pH value changes from HI to LO or vice versa, the system ensures that the new pHvalue is consistent for this delay period to be taken as a genuine violation.

The display shows r Hi xx.xx.

Set the pH value for recorder output high.

Setting Time, Date and Batch No.: To set the Time, Date or Batch No. bring the respectiveparameter on display using the DISP key. Press NO. The display digit will flash. Now enter thecorrect Time, Date or Batch No. using the cursor control keys and press DISP key.

This completes the programming.

IT IS RECOMMENDED THAT A RECORD OF PROGRAMMED DATA IS KEPT AS AREFERENCE FOR FUTURE CHANGES OR REPROGRAMMING.

OPTIMISING THE CONTROL PROCESS

With this system of dosing the operator has 5 parameters through which the whole pH controlsystem can be optimised.

Strength of dosing reagent

Flow rate of dosing reagent / second (with dosing element on)

Setting of HH limit

Setting of H2 limit

Setting of mark time A (Dose time)

Setting of space time A (Mixing or response time)

Setting of mark time B (Dose time)

Setting of space time B (Mixing or response time)

The strength of the dosing reagent and the flow rate are determined by the processrequirement and past experience can be used as a guideline. However this may be later bechanged to optimise the process.

The H2 limit is set at such a value that permits convenient dose quantities to be used withouta risk of one dose quantum bringing the pH value from H2 to less than H1. The “Mark” time Ais set such that one Mark doses changes the pH of the process from H1 to L1 band. TheSpace time A is set to the time that is required for one “Mark” of dose to mix and result in adisplay of a stable process pH value.

Similarly HH limit and Mark Space B time settings are made to provide a good approachcontrol on the pH value. This setting will depend heavily on the titration curve of the process.

A few batches are processed with the above settings and during these trials a detailed recordof time Vs pH is made with a clear note on every dose, the time of dose and duration. Nowplot a X-Y graph with time on the X-axis and pH on the Y-axis. A clear picture of theeffectiveness of control can be seen in this graph. It will now be possible to decide whichparameters need to be changed to improve the control and optimise the process.

Case 1: If the graph shows that the pH control is very gradual and slow and the time takenfor the pH to change is high then the control can be improved by

increasing the “Mark A”time or

increasing the concentration of the dose reagent or

by increasing the flow rate of the reagent or

by setting a lower H2 limit

by increasing the “Mark B ″ time

Case 2: If the graph shows that the pH change with dose is very rapid (eg. While controllingHigh pH the end pH value is going Low), thenThe Mark time needs to be reduced or

Reagent strength needs to be reduced or

The reagent flow rate needs to be reduced or

The “Space″ time is insufficient and must be increased.

Two extreme cases have been taken to show the possibilities and in each application the statewill be different and optimisation has to be judiciously done. It is important though to record allexperimentation and results in complete detail so that the final settings can be optimised withminimum iterations and there is a record available for help in future trouble shooting.

ELECTRODE CALIBRATION

The DPH 503 allows you to calibrate the electrode with any two buffer solutions, in any order orperform a Standardisation only. The instrument recognises three buffers viz. 4.01 @ 25° C7.00 @ 25 ° C and 10.00 @ 25°. If any of these buffers are used, the instrument automaticallycorrects the pH of the buffer for that temperature.

The instrument also permits blind calibration of the pH electrode from the transmitter using anyof the above three buffers.

CALIBRATION FROM THE KEYBOARD: To calibrate the pH electrode from the keyboardproceed as follows.

SINGLE POINT CALIBRATIONPress ESC to bring the instrument to the pH display mode.

Press PRT/CAL key. The dislay shows PRT? Press NO

The display shows pH CAL? Press YES

The display shows B1 ready? Asking if the electrode is in the buffer.

Dip the pH electrode and temperature sensor in the first buffer (any one of 4.01, 7.00 or10.00) and Press YES. The flashing of the ? sign will stop and the display will show busy whilethe system reads the input from the electrode. After a stable reading is taken the display willshow B2 ready?

If only a single point calibration is to be done Press NO to end calibration.

The system will compute the Asymmetric potential of the electrode retaining the existing slopevalue and display AP=XXX followed by an error message if any.

If the AP of the electrode is within +50 mV no error message is shown. Press YES to acceptthe calibration and update memory or ESC to reject the calibration.

If the AP is > + 50 mV the display alternates between AP=xxx and CAL ERR 1.

In this case the system will not accept the calibration and a change of electrode is required.

POINT CALIBRATIONPress ESC to bring the instrument to the pH display mode.

Proceed as in Single point Calibration till the message b2 ready is seen.

Dip the electrode in the second buffer (again one of 4.02, 7.00 or 9.18) and press YES.

The system now computes the AP and SLOPE of the electrode and displays AP=xxx andS=x.xxx with appropriate warnings as earlier.

CAL ERR 1 for AP> + 50 mV (Calibration rejected)

CAL ERR 2 for slope <0.900 or > 1.050 (Calibration rejected)

If the pH reading in any of these buffers does not confirm to the expected output or a differentsolution is used to standardise the electrode, the system displays a message CAL ERR 3 and willnot proceed with the calibration.

The calibration can be aborted at any time by pressing the ESC key.

GRAB SAMPLE CALIBRATION:

It is possible that in some long duration batches, there is a need to recalibrate the electrodebecause of a small shift in electrode standardisation. In such cases where the electrode cannot be removed for recalibration with buffers the contents of the reactor itself can be used forstandardisation. To do this enter the pH calibration procedure by pressing YES at pH Cal?

Prompt. At the b1 ready prompt press NO.

The instrument will now show b xx.xx

Enter the correct pH value of the reactor contents and press YES. The instrument will performa single point calibration at this pH and show.

AP= xxx

All errors applicable to Single point Calibration are applicable here.

REMOTE CALIBRATION FROM THE TRANSMITTERIn this case of remote calibration from the transmitter the system automatically invokes Singlepoint or 2 point calibration as programmed into the system by the user.

Press ESC to bring the instrument to the pH display mode

Press RT/CAL key. The Display shows PRT? Press NO.

The display shows pH CAL? Press NO.

The display shows REM CAL Press YES.

This enables Remote Calibration as per the method entered under Setup.

SINGLE POINT CALIBRATIONPress the switch on the transmitter. An acknowledge beep will be received.On getting the ready beep at the transmitter, Dip the electrode in buffer (one of 4.01, 7.00 or10.00 only) and Press the CAL switch on the Transmitter. The system calculates the AP andif there is no ERROR gives an acceptance tone in the form of 3 second beeps separated bythree second intervals. Press the CAL switch again to acknowledge and the calibrationprocedure is complete.

2 POINT CALIBRATIONOn getting the ready beep at the transmitter Dip the electrode in buffer (one of 4.01, 7.00 or10.00 only) and press the CAL switch on the Transmitter. The system reads the input andgives a ready beep again. Now dip the electrode in the second buffer and press the CALswitch again. The system calculates the AP and Slope and if there is no error, gives anacceptance tone in the form of 3 second beeps separated by three second intervals. Press theCAL switch again to acknowlege and the calibration procedure is complete.

In case of an error in calibration, the system does not give the acceptance tone but gives anERROR tone in the form of 1 second beeps separated by 1 second intervals. Press the CALSwitch again to acknowledge the Error.

In this case the CALIBRATION PERFORMED IS IGNORED AND THE PREVIOUS VALUESARE RETAINED.

Temperature Sensor Calibration:

Place the temperature sensor in a solution of known temperature

Press ESC to brig the instrument to the pH display mode.

Press PRT/CAL key. The Display show PRT? Press NO.

The display shows pH Cal? Press NO,

the display shows rem CAL? Press NO

The display shows tem cal. Press YES

The display now shows 000.0

Enter the solution temperature and press YES

The display shows dt xxx.xx

i.e. (dt being the difference beteen the factory calibration and the actual temperature entered)Press YES

The temperature sensor is now calibrated.

NOW THE INSTRUMENT IS READY TO CONTROL YOUR PROCESS

EARTH

NEUTRAL

PHASE

DRYSHLD

CALTMPpH

-V+V

AGBATCH

WASHHALT

GNDHI

LO

FU

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250

mA

COM

NO

FUSE 250mA

FUSE 250mA

NO

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FUSE 250mA

NO

COM

FUSE 250mA

NO

COM

FUSE 250mA

NO

COM

WA

SH

HIG

HR

L4LO

WR

L5

pH

+V

-V

GND

ZERO

ATC (RTD )

ATC (RTD )

REFERENCE

SOLUTION GROUND

GLASS

SPAN

TEMP.

CAL

TEMP

ZERO SPAN

PO

WE

R L

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FIL

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RED

BROWN

BLUEYELLOW

ORANGE

GR

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WH

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pH e

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The DPH 503 control system comprises a pH electrode housing a pH transmitter and thecontroller. Installation and commissioning of the system comprises the following:

Conditioning of the pH electrodeAssembly of the electrode housingConnecting the electrode, temperature and level sensor to the transmitterConnecting the transmitter to the ControllerConnecting the Dosing elements to the controllerConnecting the external digital inputs to the controllerProgramming the controllerElectrode calibration

Conditioning the pH ElectrodeRemove the pH Electrode from the packing boxClean any salt deposits from the electrode by rinsing Distilled WaterUncover the filling hole and add filling solution to the electrode if required. In the case of GE1filled electrodes this step is not required.Shake the electrode like a clinical thermometer to remove any air bubblesSoak the electrode in pH Electrode Storage Solution for a few hours, preferably overnight.IMP: Never touch the electrode bulb with the hand. Avoid wiping or rubbing of the electrodebulb to reduce polarisation error.

Assemble the Electrode Housing as per the drawing supplied with the housing.Connect the pH Electrode and the Temperature sensor cables to the transmitter as shown inthe connection diagram. IT IS IMPORTANT TO ENSURE THAT THE VESSEL GROUNDCONNECTIONS IS FIRMLY CONNECTED TO THE PROCESS SOLUTION GROUND.

Connect the Transmitter to the Controller as shown in the connection diagram.

Connect the Dosing elements (Solenoid valves/Pumps) through the control relay terminals.IMP. The control relays are rated for 230 V, 3A resistive load. Should the dosing element havea higher rating an intermediate Contractor or Relay of an appropriate rating should be used.

Now program the controller following the instructions given under the chapter Programming.

Now Calibrate the electrode folloiwng the instructions given under Electrode Calibration.When calibrating for the first time a 2 point calibration should be done.

INSTALLATION OF DPH 503

ELECTRODE MAINTENANCE

The pH Electrode is the heart of the system and proper care in maintenance of theelectrode will go a long way in ensuring correct readings and longer life.

Inspect the electrode as frequently as is possible for scratches, salt crystal buildup ormembrane/junction coating. This inspection should be done at least once a week andmore frequently if possible.

Rinse off any salt deposits with distilled water and remove any membrane deposits byrinsing. If rinsing with distilled water does not remove deposits by rinsing. If rinsing withdistilled water does not remove deposits from the membrane follow the Cleaningprocedure outlined below.

If the reference electrolyte appears to be contaminated with extraneous matter drain thereference electrode chamber, flush with fresh filling solution and refill.

CLEANING PROCEDURE

General - Rinse electrode well and soak in 0.1M HCl or 0.1 M HNO3 for half an hour.

Removal of membrane deposits

Inorganic – Soak in 0.1M tetrasodium EDTA soln. For 15 minutes.

Protein Soak in 1% pepsin in 0.1M HCl for 15 minutes.

Grease & Oil – Rinse with mild detergent or Methanol solution.

After any of these cleaning procedures, drain and refill the reference chamber and soakin storage solution for half an hours.

ERROR MESSAGES

Tmp err: In ATC mode, the system periodically reads the temperature of the solution. Ifat any time the temperature sensor readings are abnormal.i.e. Sensor is Open or Shortthis error message appears. In such a case, change the system operation to MTC modethrough ‘Program’. And Check the temperature sensor, the connections and replacesensor if necessary Calibrate the temperature sensor and resume ATC operation.

Lim err: In the programming operation, if the operator enters illogical limits for control, foreg. H1<L1 or H2 < H1, the system will not accept these limits and will respond with a‘LIM ERR’ message, and the interactive promoting display will remain at the limit whichis illogical.

Cal err 1, Cal err 2 and Cal err 3: See chapter on Electrode calibration for explanation

GLOBAL ELECTRONICS warrants its products, when properly applied and operated undernormal conditions, to be free from faulty workmanship or defective materials for a period ofONE YEAR from the date of original shipment. Global products repaired or replaced pursuantto this warranty shall be warranted for the unexpired portion of the warranty applying to theoriginal products. The liability of Global under this warranty shall exist provided that

a.The attached warranty registration card is sent back to Global within a fortnight of purchase; andb.Global is promptly notified upon discovery of such defects by Buyer; andc. The defective product is returned to ‘Global, transporation paid by Buyer or at Global’s discretion the said product is inspected and repaired at Buyer’s site; andd. Global’s examination of such product disclose that there was a defect in Global material or workmanship; ande. Global name plates and markings have not been altered or removed.

In the event the defect is determined to be within the terms of this warranty, Global agrees torepair/replace the product or the defective portion at no charge to Buyer and to pay fortransportation back to Buyer. This warranty does not apply to consumable items like electrodes,conductivity cells, temperature sensors, fuses etc. or parts which have been subject to misuse,neglect, accident or abnormal conditions of operation.

Global reserves the right to make changes in design and specifications without notice andwithout any obligation of such changes on units purchased. Until superseded or in contractualform, this warranty is expreslly in lieu of all other liabilities and obligations on the part of GlobalElectronics.

MODEL :

SERIAL NO:

DATE OF SALE:

for GLOBAL ELECTRONICS

WARRANTY