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TPS WP-80M Manual Download Page 44

Page 44

20.3 pH Temperature Compensation

The  slope  of  a  pH  sensor  is  affected  by  temperature.  This  effect  is
compensated  for  either  by  using  an  Automatic  Temperature
Compensation  (ATC)  sensor  or  by  entering  the  sample  temperature
manually.  Figure  20-3  shows  the  slope  of  a  pH  sensor  at  various
temperatures.

-600

-400

-200

0

200

400

600

0

7

14

m

V

Electrode
Potential (mV) at
0 oC (54mV/pH)

Electrode
Potential (mV) at
50 oC (64mV/pH)

Electrode
Potential (mV) at
100 oC
(74mV/pH)

pH Electrode Response, as a Function of Temperature

pH

Figure 20-3

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Summary of Contents for WP-80M

Page 1: ...dbook is clearly listed Sub sections have also been included to enable you to find the information you need at a glance 2 Introduction The introduction has a diagram and explanation of the display and controls of the WP 80M It also contains a full listing of all of the items that you should have received with your WP 80M Please take the time to read this section as it explains some of items that a...

Page 2: ...ty Ltd ABN 30 009 773 371 4 Jamberoo Street Springwood Brisbane Australia 4127 Phone 07 32 900 400 International 61 7 32 900 400 Fax 07 3808 4871 International 61 7 3808 4871 Email tps tps com au Web www tps com au ...

Page 3: ...ration Procedure 19 8 2 Calibration Notes 19 8 3 Calibration Messages 20 8 4 Manual Temperature Setting 20 9 Good Laboratory Practices GLP 21 9 1 To recall GLP information on the display 21 9 2 Failed Calibration 22 9 3 Printing GLP Information to the RS232 Port 22 9 4 Instrument Serial Number 22 9 5 Additional GLP Features 22 10 Notepad Function 23 10 1 Recording Readings into the Notepad Standar...

Page 4: ...tery 35 15 Clock Function 36 15 1 Setting the Clock 36 15 2 Displaying or Hiding the Clock 36 16 Selecting Buffers for Auto Buffer Recognition 37 17 Initialising the WP 80M 38 18 Instrument firmware version number 38 19 Troubleshooting 39 19 1 General Errors 39 19 2 pH and mV ORP Troubleshooting 40 19 3 Temperature Troubleshooting 41 20 Appendices pH Sensor Theory 42 20 1 Asymmetry of a pH Sensor ...

Page 5: ...Page 5 1 Introduction 1 1 WP 80M Display and Controls ...

Page 6: ...ative mV ORP when relative mV ORP mode is selected See section 7 Press to access the user friendly menu system which makes the WP 80M a breeze to operate and The and keys are used when calibrating temperature readout section 8 setting manual temperature compensation section 8 4 setting the clock section 15 1 setting the automatic logging period section 11 and displaying GLP information section 9 1...

Page 7: ...00 Buffer 200mL 121387 5 pH4 01 Buffer 200mL 121381 6 Battery charger 130037 7 Manual Options that may have been ordered with your WP 80M 1 Extended cable 130040 2 RS232 Serial Interface Cable 130041 3 Communication software for Windows 95 and later 130086 4 USB to Serial Adaptor requires 130041 also 130087 5 Hard Carry Case 130059 6 Battery charger lead for 12V cigarette lighter socket 130046 7 B...

Page 8: ... s Equation User can select Bendall s Equation On or Off for final pH value Temperature Compensation pH only not for mV ORP Automatic 0 to 100 o C Manual 0 to 100 o C Calibration pH Automatic standard recognition in pH4 01 pH6 86 pH7 00 pH9 18 or pH10 01 buffers pH Sensor Asymmetry Range 1 00 to 1 00 pH pH Sensor Slope Range 85 0 to 105 Input Impedance 3 x 1012 Ω mV ORP Sensor calibration not avai...

Page 9: ... transmitted to the RS232 port but is not displayed Battery Saver On Auto switch off after 5 minutes Off Continuous use Bar Graph display of battery charge level Readout of battery voltage available for troubleshooting Good Laboratory Practices Date Time and Value of last pH and Temperature calibration are stored and can be recalled or sent to the RS232 port at any time Power 6V NiMH Rechargeable ...

Page 10: ...for the WP 80M menu functions F1 Cal F1 pH available when in pH mode F2 Temp F2 Notepad F1 Recall F2 Erase F3 Print F4 Prog F1 Min F2 Sec F3 Hr Set Period F3 Mode F1 pH F2 Rel mV F3 mV F4 Bendalls F1 OFF F2 ON F4 Setup F1 Batt F1 OFF Battery Saver F2 ON Battery Saver F2 Clock F3 GLP F1 Recall F3 Print F4 Baud F1 300 F2 1200 F3 9600 F4 19200 ...

Page 11: ...pH Mode Displays pH and Temperature readings simultaneously Press to show or hide the date and time For example 7 00pH 25 0 c 31 12 12 00 00 If the temperature sensor is unplugged the manual temperature setting is displayed with 1o C resolution For example 7 00pH Man 25 c 31 12 12 00 00 3 1 2 mV ORP Mode Displays mV ORP and Temperature readings simultaneously Press to show or hide the date and tim...

Page 12: ...0mVR 25 0 c 31 12 12 00 00 If the temperature sensor is unplugged no temperature value is displayed 1000mVR 660mV F4 Zeros 1000mVR 31 12 12 00 00 Notes 1 Temperature compensation does not apply in mV ORP mode 2 The decimal point is replaced by a if a pH or Temperature calibration has failed sections 5 1 and 8 1 if the unit is initialised section 17 or if the unit has lost its factory calibration s...

Page 13: ...in display indicating that the Bendalls Equation mode is ON 7 00pHB 10 0o c 31 12 12 00 00 4 2 Selecting Extra Data Entry On or Off The User Data Entry function can be enabled or disabled as required 1 Switch the meter OFF 2 Press and hold while switching the meter back ON 3 If there is any data recorded in the Notepad memory it must be erased first The meter will automatically prompt you if this ...

Page 14: ...cognition See section 16 for a detailed explanation 4 Select pH Mode F3 Mode F1 pH Bendall s Mode may be On or Off 5 Ensure that temperature has already been calibrated or manually set see sections 8 1 and 8 4 NOTE If the decimal point in the temperature reading is shown by a then the temperature readout is not calibrated 6 Remove the wetting cap from the pH sensor 7 Rinse the pH and Temperature s...

Page 15: ...H4 01 pH9 18 or pH10 01 Buffer so that the bulb and reference junction are both covered as per the diagram in step 8 above DO NOT place the sensors directly into the buffer bottle pH9 18 and pH10 01 buffers are unstable once the bottles have been opened Discard immediately after use 13 Select pH Calibration F1 Cal F1 pH 14 When the reading has stabilised press the key to calibrate The will now be ...

Page 16: ...yed corresponds to the buffer that you are using 5 3 Calibration Messages 1 If a 1 point calibration has been successfully performed the WP 80M will display the following message and the asymmetry of the sensor For example 1 Point Cal OK Asy 0 10pH 2 If a 1 point calibration has failed the WP 80M will display the following message and the failed asymmetry value of the sensor For example 1 Point Ca...

Page 17: ...ORP mode so the temperature sensor does not need to be connected 2 Switch the meter on 3 Select Relative mV ORP Mode F3 Mode F2 Rel mV The display should now be showing Relative mV ORP on the top line with absolute mV ORP or date and time on the bottom line For example 1000mVR 25 0 c 660mV F4 Zeros 1000mVR 25 0 c 31 12 12 00 00 Press to alternate between absolute mV ORP or the clock on the bottom ...

Page 18: ... 0mVR 25 0 c 660mV F4 Zeros or 0mVR 25 0 c 31 12 12 00 00 8 The WP 80M Relative mV ORP mode is now zeroed and is ready for use The readout can be re zeroed by pressing the key whenever required 7 1 Notes 1 The Relative mV ORP offset is retained in memory when the WP 80M is switched off even when the battery is removed 2 The Relative mV ORP zero is reset when leaving Relative mV ORP mode see sectio...

Page 19: ... Temp 5 The reading from the sensor is now displayed on the right of the display and the value you are going to set is shown on the left For example 25 0 20 0 c Set F1 Cal 6 When the reading on the right has stabilised press the and keys until the reading on the left shows the same temperature as the mercury thermometer 7 Press the key to calibrate the temperature readout Alternatively press the k...

Page 20: ...Manual Temperature Setting If the temperature sensor is not connected the temperature of the sample solution must be set manually for accurate pH measurements A separate thermometer will be required for this 1 Switch the meter on 2 Measure the temperature of the sample 3 Select Temperature Calibration F1 Cal F2 Temp 4 The current temperature setting is now displayed For example 25 0 Man Temp Set F...

Page 21: ...nstrument model firmware version number and instrument serial number are displayed along with a prompt describing how to scroll through the GLP information For example WP80M V5 2 S1234 More Back 5 Press the key to sequentially scroll through the GLP information for all parameters Press the key to scroll back to previous data The sequence of information displayed is shown below Press to abort at an...

Page 22: ...F3 GLP F3 Print 4 The GLP information is sent to the RS232 port in formatted ASCII text For example WP80M V5 2 S1234 31 12 10 12 00 pH Asy 0 00pH 31 12 10 11 40 pH Slope 100 0 31 12 10 11 50 Temperature Offset 1 0oC 31 12 10 12 00 ENDS 9 4 Instrument Serial Number In case the serial number that is fitted to the rear of the WP 80M is removed or becomes illegible it is also available on the WP 80M d...

Page 23: ...n as required The maximum number of readings that can be stored in the Notepad is 2600 10 2 Recalling Records from the Notepad Standard To recall records from the Notepad onto the WP 80M display 1 Select the Notepad menu F2 Notepad 2 Select F1 Recall from the menu 3 Record number 1 is now displayed for example 7 00pH 25 0 c 1 F2 Clock 4 Press to alternatively display the date and time or the data ...

Page 24: ...ress to move the cursor left to make any corrections Any of the characters may be left blank if required 4 When setting the last character the display changes to indicate that one more press of the will save the data For example 1 123 ABCD F1 F2 End Set 5 Press to save the data Alternatively press to quit without recording the data 6 The meter now returns to pH and Temperature measurement with a p...

Page 25: ...ween the data and the date time for this record For example 7 00pH 25 OO c 1 123 ABCD 31 12 12 00 00 1 F2 Data 5 Press to move forward through the records Press to move backward through the records Press and hold the or keys to roll rapidly through the readings 6 Press to exit back to normal measurement mode 10 5 Erasing Records from the Notepad To erase all records from the Notepad 1 Select the N...

Page 26: ...ired 2 Connect the other end of the RS232 cable to an RS232 Printer or to COM1 or COM2 of a PC 3 Ensure that the baud rate for the printer or PC and the WP 80M are the same If necessary alter the baud rate of the WP 80M see section 12 1 The WP 80M uses XON XOFF protocol Ensure that the printer is set accordingly 4 Select the Notepad menu F2 Notepad 5 Select F3 Print from the menu Printing starts a...

Page 27: ...has been correctly set select whether this period is in minutes seconds or hours Press to save the period as minutes Press to save the period as seconds Press to save the period as hours eg If the period was set to 05 followed by then the WP 80M will automatically log a record every 5 seconds 5 The WP 80M will ask if the records are to be logged into the Notepad or sent directly to the RS232 port ...

Page 28: ...0 The WP 80M will beep each time a record is sent to the RS232 port 8 Press to stop automatic logging Notes 1 The clock must be set before the WP 80M will allow automatic logging to start The message Clock Not Set is displayed if the clock is not set 2 The Battery Saver function section 13 is disabled while the meter is in Automatic Data logging mode to stop the meter switching off while logging d...

Page 29: ...ords can be sent directly to the RS232 port rather than stored in memory during automatic data logging See section 11 for details 12 3 RS232 Configuration The WP 80M RS232 configuration is 8 bits No Parity 1 Stop Bit XON XOFF Protocol 12 4 Communication and Statistical Software Communication between the WP 80M and a PC can be handled with any RS232 communication software WinTPS RS232 communication...

Page 30: ...ata ends with the message ENDS cr Erase logged data E cr Erases all logged records from the WP 80M memory Returns the message ERASED cr to confirm that the records have been erased Request status information S cr Returns the model name firmware version number instrument serial number and number of logged readings in memory eg WP80M V5 2 S1234 150 cr where are spaces Note that the number of logged ...

Page 31: ... 6 characters right justified uuu is the pH mV ORP unit description which can be any of the following pH for pH readout pHB for pH readout with Bendalls Equation ON mV for Millivolts ORP readout mVR for Relative Millivolts ORP readout TTTTTT is Temperature data 6 characters right justified uuu is the Temperature unit description which can be either of the following oC for real Temperature data oCm...

Page 32: ... ENDS 12 8 Importing Data into Microsoft Excel The following procedure details the method for importing a WP 80M text data file into Microsoft Excel 1 Start Microsoft Excel and select File Open 2 In the Files of type pull down box choose Text Files prn txt csv 3 Navigate to the folder where your data file is stored and double click it to start the Text Import Wizard Note The default data folder fo...

Page 33: ...ss Next after the column breaks have been inserted 6 Simply press Finish at step 3 of the Text Import Wizard TPS recommends that the data format for each column be set once the data is in spreadsheet format For help on formatting the data columns charting graphing or other operations please consult the Microsoft Excel help file Alternatively please contact TPS and we will try to provide further as...

Page 34: ...e battery saver function for continuous use Press to enable the battery saver function The meter will switch itself off if no key has been pressed for five minutes Press to quit the battery saver menu and retain the current setting Notes 1 For troubleshooting purposes the battery volts can also be displayed in the battery saver menu Press to display battery volts 2 The symbol flashes when the batt...

Page 35: ...harge the battery 1 Plug the battery charger solar panel or car cigarette lighter adaptor into the Charger RS232 socket DO NOT plug into the Temperature socket as this will damage the WP 80M 2 Charge for approximately 8 hours for full capacity The WP 80M has special circuitry to prevent overcharging so the charger can be used continuously 3 To ensure optimum battery life and capacity the WP 80M sh...

Page 36: ... minutes Press the and keys until the minutes are correct 7 Check that the date and time are correct Press to save the settings If any changes are needed press the key to move left to the desired position Press to quit without resetting the clock Notes 1 The WP 80M does not test for a valid day of the month when setting the clock eg attempting to enter 31 02 10 is not corrected 2 The WP 80M does t...

Page 37: ...ect F1 7 00pH Buffer F2 6 86pH The arrow indicates the current selection 4 Press to select pH7 00 as the primary buffer Press to select pH6 86 as the primary buffer Press to quit buffer selection and retain the current setting 5 The display will now show the currently selected high pH buffer Select F1 9 18pH Buffer F2 10 0pH The arrow indicates the current selection 6 Press to select pH9 18 as the...

Page 38: ...n WP80MsV5 2 S1234 Meat pH ORP o C 4 The meter then displays pH and Temperature Note that the decimal points have been replaced with a to indicate that the unit requires recalibration 5 The following items are reset when the WP 80M is initialised Any logged data is erased Calibration settings for pH and temperature are re set to factory defaults Extra Data Entry is re set to ON 18 Instrument firmw...

Page 39: ...ature see section 8 1 Flashing symbol Battery is below 5 60 volts Recharge the battery Note that the unit will switch itself off when the battery falls below 5 00 volts Meter displays the word OFF and switches off Battery is below 5 00 volts Recharge the battery If this fails check the charger If charger OK replace the battery Meter will not turn on Battery is exhausted Recharge the battery If thi...

Page 40: ...rence junction as per instructions supplied with the sensor Flush with distilled water and replace electrolyte 2 Point calibration fails Slope is less than 85 0 1 Incorrect primary buffer 2 Glass bulb not clean 3 Sensor is aged 4 Connector is damp 5 Buffers are inaccurate Ensure that you are using the buffers which the WP 80M has been set to automatically recognise see section 16 Clean glass bulb ...

Page 41: ...until dissolved Replace electrolyte Inaccurate readings even when calibration is successful Reference junction blocked Clean reference junction as per instructions supplied with the sensor Displays 7 00 for all solutions Electrical short in connector 1 Check connector Replace if necessary 2 Replace sensor Displays 4 5 pH for all solutions Glass bulb or internal stem cracked Replace sensor Display ...

Page 42: ...reference junction A saturated solution of KCl is used to make contact with the sample It is vital that the KCl solution has an adequate flow rate in order to obtain stable accurate pH measurements 20 1 Asymmetry of a pH Sensor An ideal pH sensor produces 0 mV output at 7 00 pH In practice pH sensors generally produce 0 mV output at slightly above or below 7 00 pH The amount of variance from 7 00 ...

Page 43: ...it In practice pH sensors usually produce slightly less than this The output of a pH sensor is expressed as a percentage of an ideal sensor For example an ideal sensor that produces 59mV pH unit has 100 Slope An sensor that produces 50 15mV pH unit has 85 Slope see Figure 20 2 600 400 200 0 200 400 600 0 7 14 mV 85 Slope at 25 oC 50 15mV pH 100 Slope at 25 oC 59mV pH Response of pH Electrode as a ...

Page 44: ...ure Compensation ATC sensor or by entering the sample temperature manually Figure 20 3 shows the slope of a pH sensor at various temperatures 600 400 200 0 200 400 600 0 7 14 mV Electrode Potential mV at 0 oC 54mV pH Electrode Potential mV at 50 oC 64mV pH Electrode Potential mV at 100 oC 74mV pH pH Electrode Response as a Function of Temperature pH Figure 20 3 ...

Page 45: ...ipment incorrect calibration incorrect operation or from interpretation of information derived from the equipment Specifications are subject to change without notice This warranty becomes invalid if modifications or repairs are carried out on this unit by unauthorised persons There are no express or implied warranties which extend beyond the face hereof Procedure for Service Please read service de...

Page 46: ...Your equipment will be repaired and returned to you by express air freight where possible For instruments beyond warranty period a repair cost will be calculated from parts and labour costs and emailed to you If you decline to have the equipment repaired the complete instrument will be returned to you freight paid not serviced TPS Pty Ltd has only one service location which is located at our facto...

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