manualshive.com logo in svg

TPS WP-90, Руководство пользователя, Страница: 45 / 48

Поделиться
Скачать
TPS WP-90 Скачать руководство пользователя страница 45

Page 45

20.3 pH Temperature Compensation

The slope of a pH sensor (section 20.2) is affected by temperature. This effect is
compensated for either by using an Automatic Temperature Compensation (ATC)
probe 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

Millivolts

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

20.4 Checking the reference junction of a pH sensor

If pH readings are inaccurate or unstable, the reference junction of the sensor may
be blocked. The following test can be performed to determine if the reference
junction of a pH sensor is making adequate contact with the sample solution.
1.

 

Calibrate the 

WP-90

, as per section 5.1.

2.

 

Dilute 1 part of pH6.88 buffer with 9 parts of distilled water.

3.

 

Measure the pH of the diluted buffer. The result should be 7.06 +/-0.02 pH.

4.

 

If the value obtained is outside of these limits, then clean the reference
junction, as per the instructions supplied with the pH sensor.

5.

 

Re-calibrate the 

WP-90

 and repeat the test.

6.

 

If the value obtained is still outside 7.06 +/-0.02 pH, then the sensor should
be replaced.

Содержание WP-90

Страница 1: ...duction has a diagram and explanation of the display and controls of the WP 90 It also contains a full listing of all of the items that you should have received with your WP 90 Please take the time to read this section as it explains some of items that are mentioned in subsequent sections 3 Main Section The main section of the handbook provides complete details of the WP 90 including operating mod...

Страница 2: ...ages 19 6 mV Calibration 20 7 Relative mV Calibration 20 7 1 Notes 20 8 Temperature Calibration 21 8 1 Calibration Procedure 21 8 2 Calibration Notes 22 8 3 Calibration Messages 22 8 4 Manual Temperature Setting 22 9 Good Laboratory Practices GLP 23 9 1 To recall GLP information on the display 23 9 2 Failed Calibration 25 9 3 Printing GLP Information to the RS232 Port 25 9 4 Instrument Serial Numb...

Страница 3: ...the Clock 36 15 2 Displaying or Hiding the Clock 36 16 Selecting Buffers for Auto Buffer Recognition 37 17 Initialising the WP 90 38 18 Instrument firmware version number 38 19 Troubleshooting 39 19 1 General Errors 39 19 2 Specific Ion pH and mV Troubleshooting 40 19 3 Temperature Troubleshooting 41 20 pH Sensor Fundamentals 43 20 1 Asymmetry of a pH Sensor 43 20 2 Slope of a pH Sensor 44 20 3 pH...

Страница 4: ...Page 4 1 Introduction 1 1 WP 90 Display and Controls ...

Страница 5: ... Relative mV mode is selected section 7 Press to access the user friendly menu system which makes the WP 90 easy to operate and The and keys are used for calibrating temperature readout section 8 1 setting the clock section 15 1 setting the automatic logging period section 11 and displaying GLP information section 9 1 The key is also used to initialise the WP 90 at turn on See section 17 Switches ...

Страница 6: ...hat may have been ordered with your WP 90 1 RS232 Serial Interface Option 130039 includes cable and communication software for DOS 2 Communication software for Windows 3 1 95 NT 130086 3 Hard Carry Case 130059 4 Battery charger lead for 12V cigarette lighter socket 130046 5 Solar Panel 130012 6 RS232 Printer 130031 Sensors Your choice of a complete range of Ion Selective Reference pH and Redox sen...

Страница 7: ...ecific Ion Specifications Input Impedance 3 x 1012 Ω Asymmetry Range Auto detection Slope Range 50 0 to 110 0 Temperature Compensation Automatic 0 to 100 O C Calibration Automatic calibration in user definable standards pH Specifications Input Impedance 3 x 1012 Ω Asymmetry Range 1 00 to 1 00 pH Slope Range 85 0 to 105 0 Temperature Compensation Automatic 0 to 100 O C Calibration Automatic calibra...

Страница 8: ...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 results of last Specific Ion pH and Temperature calibration are stored in memory This information can be recalled or sent to the optional RS232 port at any time Power 6V NiMH Recharge...

Страница 9: ...l display mode to perform the following tasks Press to record current data plus date and time into memory Press to show or hide date and time Press to start and stop automatic logging If logging period is set to zero press to transmit current reading plus date and time to the RS232 port Press to zero Relative mV when Relative mV mode is selected Press to access the user friendly menu system as det...

Страница 10: ... in all modes F3 Ion Sec only in Ion mode F2 Notepad F1 Recall F2 Erase F3 Print F4 Prog F1 Min F2 Sec F3 Hr Period F3 Mode F1 Ion F2 pH F3 mV F4 Rel mV F4 Setup F1 Batt F1 OFF F2 ON F2 Clock F3 GLP F1 Recall F3 Print F4 Baud F1 300 F2 1200 F3 9600 These functions available when RS232 option is fitted ...

Страница 11: ... Select ppM ppK as the unit of measurement Select Ion Mode F1 ppM ppK F2 Exp Press to select readout in ppM parts per million and ppK parts per thousand The WP 90 will automatically select the range that provides the best resolution for the sample being measured 3 Select the type of Specific Ion to be measured F1 Mono F2 Mono F3 Di F4 Di Press for Monovalent Cation e g Na Press for Monovalent Anio...

Страница 12: ... Standard to be used for calibration The Secondary Standard must be at least 2 to 100 times higher or lower than the Primary Standard 10 00ppM Sec Std F1 F2 Set Use the and keys to set the first digit The numbers scroll from 0 to 9 plus the decimal point Press to move to the next digit then use the and keys to set it Continue moving from digit to digit until the value of the Secondary Standard has...

Страница 13: ...fic Ion to be measured F1 Mono F2 Mono F3 Di F4 Di Press for Monovalent Cation e g Na Press for Monovalent Anion e g F Press for Divalent Cation e g Cu2 Press for Divalent Anion e g S2 4 Enter the value of the Primary Standard to be used for calibration 1 0010 00 Pri Std F1 F2 Set Use the and keys to set the first digit The numbers scroll from 0 to 9 Press to move to the next 2 digits then use the...

Страница 14: ...oll from 0 to 9 Press to move to the next 2 digits then use the and keys to set each in turn the decimal point is fixed in the second position Press to move the 10 then use the and keys to set it as 10 or 10 Press to move to the next 2 digits then use the and keys to set each in turn For example 1 0010 01 is 1 00 x 101 in units of the operator s choice e g Molar 1 0010 01 is 1 00 x 10 1 in units o...

Страница 15: ...brated 5 Rinse the Ion Selective Reference and Temperature sensors in distilled water and blot dry Primary Calibration 6 Place the Ion Selective Reference and Temperature sensors into the Primary Standard Ensure that any Ionic Strength Adjusting Buffer ISAB that may be required has been added see the Ion Selective Electrode s handbook A magnetic stirrer providing constant gentle stirring generally...

Страница 16: ...nstant gentle stirring generally improves stability 10 Select Secondary Calibration F1 Cal F3 Ion Sec The following message should be displayed The current reading is displayed on the top left A in the reading indicates that the WP 90 is currently not calibrated 0 123ppM 25 0O c F1 Cal at0 100ppM When the reading has stabilised press to perform a Secondary Calibration A in the display will be repl...

Страница 17: ... value displayed corresponds to the standard that you are using Alter the set up if necessary see section 3 4 3 Calibration Messages 1 If a Primary Calibration has been successfully performed the WP 90 will display the following message and the offset value of the sensor For example Primary Cal OK Offset 1 0mV 2 If a Secondary Calibration has been successfully performed the WP 90 will display the ...

Страница 18: ...r so that the bulb and reference junction are both covered DO NOT place the sensors directly into the buffer bottle 9 Select pH Calibration F1 Cal F1 pH 10 When the reading has stabilised press the key to calibrate If a 1 point calibration has been performed the will not be removed until a full 2 point calibration has been performed 11 Rinse the pH and Temperature sensors in distilled water and bl...

Страница 19: ...ds to the buffer that you are using 5 3 Calibration Messages 1 If a 1 point Calibration has been successfully performed the WP 90 will display the following message and the asymmetry value of the sensor For example 1 Point Cal OK Asy 0 10pH 2 If a 1 Point Calibration has failed the WP 90 will display the following message and the failed asymmetry value of the sensor For example 1 Point Cal Fail As...

Страница 20: ...25 0O c 500mV F4 Zeros or 1000mVR 25 0O c 31 12 12 00 00 Press to alternate between absolute mV or the clock on the bottom line 4 Remove the wetting cap from the Redox sensor 5 Rinse the sensor in distilled water and blot dry 6 Place the Redox sensor into a sample of the known standard Ensure that the platinum tip and reference junction are both covered When the reading has stabilised press the ke...

Страница 21: ...rature Calibration F1 Cal F2 Temp 5 The reading from the probe is now displayed on the right of the display and the value you are going to set is shown on the left A in the reading indicates that the WP 90 is currently not calibrated For example 25 0 24 0O 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 ...

Страница 22: ...ure calibration has failed the WP 90 will display the following message and the failed offset value of the probe Calibrate Fail Offset 10 5O c 8 4 Manual Temperature Setting If the temperature sensor is not connected the temperature of the sample solution must be set manually for accurate Specific Ion and pH measurements A separate thermometer will be required for this 1 Switch the meter on 2 Meas...

Страница 23: ...LP menu F4 Setup F3 GLP 3 Select F1 Recall 4 The instrument model firmware version number and instrument serial number are displayed along with a prompt describing how to scroll through the GLP information WP90 V1 0 R1234 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 displaye...

Страница 24: ... 24 GLP Display sequence WP90 V1 0 R1234 More Back Ion Offs 10 0 31 12 98 11 00 Ion Slope 99 0 31 2 98 11 10 pH Asy 0 10pH 31 12 98 11 20 pH Slope 99 0 31 12 98 11 30 Temp Offset 1 0O c 31 12 97 11 40 Exit ...

Страница 25: ...g GLP Information to the RS232 Port The GLP information stored in the instrument s memory can be sent to a printer or PC via the RS232 port This function is available only when the optional RS232 port is fitted Switch the meter on Ensure that the WP 90 RS232 cable is connected to the instrument and to the printer or PC Select the GLP menu F4 Setup F3 GLP Select F3 Print The GLP information is sent...

Страница 26: ...n pH mV Temp where R1234 is the serial number The serial number is displayed when recalling the GLP information section 9 1 The serial number is included on the printout of GLP information section 9 3 9 5 Additional GLP Features Another GLP requirement is to record the date and time of every reading The WP 90 does this for you when readings are recorded either with the Notepad function section 10 ...

Страница 27: ... number of readings that can be stored in the Notepad is 150 10 2 Recalling Records from the Notepad To recall records from the Notepad onto the WP 90 display 1 Select the Notepad menu F2 Notepad 2 Select F1 Recall from the menu 3 Record number 1 is now displayed For example 100 0ppM 25 0O c 1 F2 Clk 4 Press to alternate between the data and the date and time for this record For example 100 0ppM 2...

Страница 28: ...nect one end of the RS232 cable to the Charger RS232 socket of the WP 90 The charger optional solar panel or optional car battery lead can be connected into the spare socket on the cable for long term use if required 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 90 are the same If necessary alt...

Страница 29: ... 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 For example if the period is set to 05 followed by then the WP 90 will automatically log a record every 5 seconds 5 If the optional RS232 port is fitted the WP 90 will ask if the records are to be logged into the Notepad ...

Страница 30: ...0 will beep each time a reading is recorded If the WP 90 is sending records directly to the RS232 port the display will look like this 100 0ppM 25 0O c Sending 12 00 00 The WP 90 will beep each time a record is sent to the RS232 port 8 Press to stop automatic logging 9 Note The clock must be set before the WP 90 will allow automatic logging to start The message Clock Not Set is displayed if the cl...

Страница 31: ...iod is set to greater than zero see section 11 Records can be sent directly to the RS232 port rather than stored in memory during automatic datalogging See section 11 for details 12 3 RS232 Configuration The WP 90 RS232 configuration is 8 bits No Parity 1 Stop Bit XON XOFF Protocol 12 4 Communication and Statistical Software Communication between the WP 90 and a PC can be handled with any RS232 co...

Страница 32: ...ata ends with the message ENDS cr Erase logged data E cr Erases all logged records from the WP 90 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 WP90ssV1 0sR1234s9999 cr where s are spaces Note that the number of logge...

Страница 33: ...l readout of Specific Ions s s is one space s s are spaces TTTTTTTT is the Temperature Data maximum 8 characters right justified uuu is the Temperature unit description Either oCs s for real temperature data where s s is 1 space or oCm for manual temperature compensation data s s is one space dd mm yy is the date month and year data s s is one space hh mm ss is the hours minutes and seconds data W...

Страница 34: ...ing the G command section 12 5 the computer must respond with a character after receiving each line For example WP90 V1 0 R1234 31 12 98 12 00 Ion Offset 10 0mV 31 12 98 11 00 Ion Slope 99 0 31 12 98 11 10 pH Asy 0 10pH 31 12 98 11 20 pH Slope 99 0 31 12 98 11 30 Temperature Offset 1 0oC 31 12 98 11 40 ENDS ...

Страница 35: ... has been pressed for five minutes Press to quit the battery saver menu and retain the current setting 4 For troubleshooting purposes the battery volts can also be displayed in the battery saver menu Press to display battery volts 14 Recharging the Battery The symbol flashes when the battery drops below 5 60 volts The battery should be recharged at this point If the battery is not recharged the WP...

Страница 36: ...utes Press the and keys until the minutes are correct 7 Check that the date and time are correct If any changes are needed press the key to move left to the desired position 8 Press when the cursor is in the minutes position to save the settings Press to quit without resetting the clock Note The WP 90 does not test for a valid day of the month when setting the clock eg attempting to enter 31 02 96...

Страница 37: ...ain the current setting 4 The display will now show the currently selected high pH buffer Select F1 9 23pH Buffer F2 10 0pH The arrow indicates the current selection 5 Press to select pH9 23 as the high pH buffer Press to select pH10 00 as the high pH buffer the display shows 10 0 for the latter but this buffer is stored as pH10 00 6 Press to quit buffer selection and retain the current setting 7 ...

Страница 38: ...The meter then displays Specific Ion and Temperature Note that the decimal points have been replaced with a to indicate that the unit requires re calibration Note When the WP 90 is initialised the primary pH buffer is re set to pH6 88 and the high pH buffer is re set to pH9 23 See section 16 if you wish to use pH7 00 and or pH10 00 buffers 18 Instrument firmware version number If you need to phone...

Страница 39: ...lf 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 1 Battery is exhausted 2 Faulty Instrument Recharge the battery If this fails check the charger If charger OK replace the battery Return to factory for repair Battery doe...

Страница 40: ...or reference sensor Flush with distilled water and replace electrolyte 2 Point calibration fails Specific Ion slope is less than 50 or pH Slope is less than 85 1 Incorrect primary Ion Standard or pH Buffer 2 Ion sensor surface or pH glass bulb not clean 3 Sensor is aged 4 Connector is damp 5 Ion Standard or pH Buffers are inaccurate Ensure that you are using the primary Ion Standard or pH Buffer f...

Страница 41: ... electrolyte chamber with warm distilled water 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 constant Specific Ion readings or pH7 00 for all solutions Electrical short in connector 1 Check connector Replace if necessary 2 Replace sensor Displays c...

Страница 42: ...Page 42 3 Faulty instrument Return to factory for repair ...

Страница 43: ...ce 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 pH is c...

Страница 44: ...n 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 Millivolts 85 Slope at 25 oC 50 15mV pH 100 Slope at 25 oC 59mV pH Response of pH Electrode a...

Страница 45: ...20 3 20 4 Checking the reference junction of a pH sensor If pH readings are inaccurate or unstable the reference junction of the sensor may be blocked The following test can be performed to determine if the reference junction of a pH sensor is making adequate contact with the sample solution 1 Calibrate the WP 90 as per section 5 1 2 Dilute 1 part of pH6 88 buffer with 9 parts of distilled water 3...

Страница 46: ...around 6 88 or 7 00 pH depending upon the temperature readout and the primary buffer selection section 16 5 If the WP 90 is operating correctly the reading should be totally stable with the wire firmly in place If not the meter requires servicing 6 Now carefully disconnect the wire from the centre pin only make sure the other end of the wire remains connected to the outside frame of the connector ...

Страница 47: ...ation section returned to TPS Pty Ltd within 7 days No claims will be recognised without the original guarantee card or other proof of purchase This warranty becomes invalid if modifications or repairs are attempted by unauthorised persons or the serial number is missing simultaneously PROCEDURE FOR SERVICE If you feel that this equipment is in need of repair please re read the manual Sometimes in...

Страница 48: ...ired and returned to you by air express where possible For out of warranty units a repair cost will be calculated from parts and labour costs If payment is not received for the additional charges within 30 days or if you decline to have the equipment repaired the complete unit will be returned to you freight paid not repaired For full account customers the repair charges will be debited to your ac...

Отзывы:

Нет отзывов