TPS 900-I3 User manual

Congratulations !
You have purchased the latest in Benchtop Specific Ion-pH-mV-Temperature instrumentation. We
trust that your new 900-I3 will give you many years of reliable service.
The 900-I3 is a breeze to operate. This manual has been designed to help you get started, and also
contains some handy application tips. If at any stage you require assistance, please contact either
your local TPS representative or the TPS factory in Brisbane.
The manual is divided into the following sections:
1. Table of Contents
Each major section of the handbook 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 900-I3. It
also contains a full listing of all of the items that you should have received with unit. 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 900-I3, including operating
modes, calibration, troubleshooting, specifications, and warranty terms.
4. Appendices
Appendices containing background information and application notes are provided at the back
of this manual.
TPS Pty Ltd
4 Jamberoo Street
Springwood, Brisbane,
Australia, 4127
Phone : [phone]
International : 61 7 32 900 400
Fax : [phone]
International : 61 7 3808 4871
E-mail : [email protected]
Web Site : www.tpssite.com.au
900-I3
Three Channel Specific Ion-
pH-mV and Temp. Meter
Date :04-Sep-98
Author :MS
Version :3.0

2
Contents
1. Introduction...............................................................................................4
1.1 900-I3 Display and Controls................................................................................................ 4
1.2 900-I3 Rear Panel Connectors............................................................................................. 4
1.3 Menu and Function Keys..................................................................................................... 5
1.4 Numeric Keypad ................................................................................................................. 5
1.5 Enter Key............................................................................................................................ 5
1.6 Delete Key .......................................................................................................................... 5
1.7 80 Character Display........................................................................................................... 5
1.8 Unpacking Information ....................................................................................................... 6
1.9 Specifications...................................................................................................................... 7
2. 900-I3 Menu Structure..............................................................................8
3. Specific Ion Mode .....................................................................................9
3.1 Selecting Specific Ion Mode................................................................................................ 9
3.2 Setting Specific Ion Standards........................................................................................... 10
3.2.1 Setting Specific ion standards for ppM, ppK and % readouts................................................................10
3.2.2 Setting Specific ion standards for Exponential readout.........................................................................11
3.3 Specific Ion Calibration..................................................................................................... 12
3.4 Specific Ion Calibration Notes........................................................................................... 14
3.5 Specific Ion Calibration Messages..................................................................................... 14
4. pH Mode...................................................................................................15
4.1 Selecting pH Mode............................................................................................................ 15
4.2 Setting the pH Buffer Set .................................................................................................. 16
4.3 pH Calibration................................................................................................................... 17
4.4 pH Calibration Notes......................................................................................................... 18
4.5 pH Calibration Messages................................................................................................... 19
5. Absolute Millivolt Mode..........................................................................20
5.1 Selecting Absolute Millivolt Mode.................................................................................... 20
5.2 Absolute Millivolt Calibration........................................................................................... 20
6. Relative Millivolt Mode...........................................................................21
6.1 Selecting Relative Millivolt Mode..................................................................................... 21
6.2 Relative Millivolt Calibration............................................................................................ 21
6.3 Relative Millivolt Calibration Notes.................................................................................. 22
7. Temperature............................................................................................23
7.1 Temperature Calibration.................................................................................................... 23
7.2 Temperature Calibration Notes.......................................................................................... 23
7.3 Calibration Messages ........................................................................................................ 23
7.4 Manual Temperature Setting ............................................................................................. 24
8. Good Laboratory Practices (GLP).........................................................25
8.1 To recall GLP information on the display.......................................................................... 25
8.2 Failed Calibration.............................................................................................................. 27
8.3 Printing GLP Information to the RS232 Port..................................................................... 27
8.4 Instrument Serial Number.................................................................................................. 28
8.5 Additional GLP Features................................................................................................... 28

3
9. Notepad Function ...................................................................................29
9.1 Recording Readings into the Notepad................................................................................ 29
9.2 Recalling Readings from the Notepad ............................................................................... 29
9.3 Erasing Records from the Notepad.................................................................................... 30
9.4 Printing Records from the Notepad to the RS232 Port....................................................... 30
10. Automatic Datalogging ..........................................................................31
11. RS232 Port...............................................................................................33
11.1 Setting the Baud Rate.................................................................................................... 33
11.2 Sending Readings to the RS232 Port ............................................................................. 33
11.3 RS232 Configuration..................................................................................................... 33
11.4 Communication and Statistical Software........................................................................ 33
11.5 Commands .................................................................................................................... 34
11.6 Data Format .................................................................................................................. 35
11.7 GLP Data Format.......................................................................................................... 36
11.8 RS232 Port Connections................................................................................................ 36
12. Recorder Port..........................................................................................37
12.1 Recorder Port Configuration in Specific Ion Mode........................................................ 37
12.2 Recorder Port Configuration in pH Mode...................................................................... 39
12.3 Recorder Port Configuration in Absolute or Relative mV Modes................................... 39
12.4 Recorder Port Specifications.......................................................................................... 40
12.5 Recorder Port Connections............................................................................................ 40
13. Setting the Clock.....................................................................................41
14. Initialising the 900-I3 ..............................................................................42
15. Instrument firmware version number...................................................42
16. Troubleshooting......................................................................................43
16.1 General Errors............................................................................................................... 43
16.2 Specific Ion, pH and mV Troubleshooting..................................................................... 43
16.3 Temperature Troubleshooting........................................................................................ 44
17. Appendices..............................................................................................45
17.1 pH Electrode Fundamentals........................................................................................... 45
17.1.1 Asymmetry of a pH Electrode ..............................................................................................................45
17.1.2 Slope of a pH Electrode.......................................................................................................................46
17.1.3 Temperature Compensation.................................................................................................................46
17.2 Guard Connector........................................................................................................... 46
17.3 Polarisation Connector .................................................................................................. 47
17.4 Checking the reference junction of a pH electrode......................................................... 47
17.5 Determining if an instrument or pH electrode is faulty................................................... 47
18. Warranty...................................................................................................48

4
1. Introduction
1.1 900-I3 Display and Controls
1.2 900-I3 Rear Panel Connectors

5
1.3 Menu and Function Keys
Press the to function keys to select desired options within the menu system.
Additionally, these keys perform the following function directly in normal measurement mode…
:Press to record readings into the Notepad. See section 10.
Also used at turn-on to select buffers for auto buffer recognition. See section 4.2.
:Press to start or stop automatic datalogging. See section 10.
Alternatively, press to transmit current reading plus date and time to the optional RS232
port. See section 11.2.
:Press to Zero Relative mV, when Relative mV is selected. See section 6.2.
:Press to obtain context-sensitive help messages. This function is disabled within menus.
1.4 Numeric Keypad
Used to enter values during set-up and calibration. A negative sign and decimal point are provided.
1.5 Enter Key
Press the key to accept default values or those entered on the Numeric Keypad.
1.6 Delete Key
Press the key to make corrections to values entered on the Numeric Keypad.
Press and hold this key at turn-on to initialise the 900-I3. See section 14.
1.7 80 Character Display
80 character alphanumeric display with user-friendly menu and context-sensitive help system.
Shows all three Specific Ion/pH/mV Channels plus Temperature, Date and Time simultaneously.

6
1.8 Unpacking Information
Before using your new 900-I3, please check that the following accessories have been included:
Part No
Standard Kit…
1. 900-I3 3 Channel Specific Ion-pH-mV Meter........... 121162
2. Temperature/ATC Sensor.........................................121245
3. Plug-Pack Power Supply ..........................................130044
4. 900-I3 Handbook..................................................... 130050
Options that may have been ordered with your 900-I3…
1. Flexible arm type electrode holder............................130088
2. RS232 Serial Interface Option (includes cable)......... 130029
3. Recorder Output Option (includes cable).................. 130028
4. RS232 PLUS Recorder Output Option......................130049
(includes cable)
5. Communication software for Windows 3.1,..............130086
95, and NT
6. Communication software for DOS ...........................130075
7. RS232 Printer...........................................................130031
Sensors…
Your choice of a complete range of Ion Selective, Reference, pH and Redox sensors.
Other spares…
1. RS232 Interface Cable..............................................130022
2. Recorder Cable.........................................................130021
3. RS232 PLUS Recorder Cable................................... 130030

7
1.9 Specifications
Mode Range Resolution Accuracy
Specific Ions Auto-ranging in units of
ppM, ppK, % and
Exponential Notation
User selectable for 3
significant digits, 2
significant digits or Auto-
rounding.
± Least significant digit
pH 0 to 14.000 pH
0 to 14.00 pH
0 to 14.0 pH
0.001 pH
0.01 pH
0.1 pH
±0.002 pH
±0.01 pH
±0.1 pH
mV 0 to ±500.0 mV
0 to ±1500 mV
(auto-ranging)
0.1 mV
1 mV ±0.15 mV ±1 mV
Relative mV 0 to ±500.0 mV
0 to ±1500 mV
(auto-ranging)
0.1 mV
1 mV ±0.15 mV ±1 mV
Temperature -10.0 to 120.0 OC0.1 OC±0.2 OC
Additional Specific 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 OC
Calibration :Automatic calibration in user-definable standards.
Additional 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 OC
Calibration :Automatic calibration. Automatic recognition of pH4.00, 6.88, 7.00,
9.22 and 10.06 buffers. Manual entry of any other buffer value.
Additional Temperature Specifications
Temp. Sensor Offset Range :-10.0oC to +10.0oC
General Specifications
Memory :1200 readings including date and time
Automatic Logging :User-set for one reading every 1 to 90 seconds, minutes or hours.
RS232 Port (optional) :300, 1200 & 9600 baud.
8 bits, no parity, 1 stop bit, XON/XOFF Protocol.
Clock :Calendar clock displays date, month, year, hours, minutes & seconds.
Good Laboratory Practices :Date, Time and Value of last Ion and pH calibration for each Channel,
plus Temperature calibration are stored. This information can be
recalled or sent to the optional RS232 port at any time.
Power :12V DC, 50mA. Plug-pack power supply is included in standard kit.
Dimensions :270 x 210 x 75 mm
Mass :Instrument only :Approx. 1.0 kg
Full Kit :Approx. 3.0 kg
Environment Temperature :0 to 45 OC
Humidity :0 to 90 % R.H.

8
2. 900-I3 Menu Structure
A detailed breakdown of the menu system of the 900-I3 is shown below. This diagram provides a
quick reference for the menu functions available for the 900-I3.
Press the function keys in normal display mode, to perform the following tasks:
:Press to record readings into the Notepad. See section 9.1.
:Press to start or stop automatic datalogging. See section 10.
If logging period is set to zero, press to transmit current reading plus date and time to the
optional RS232 port. See section 11.2.
:Press to Zero Relative mV, when Relative mV is selected. See section 6.2.
:Press to obtain context-sensitive help messages. This function is disabled within menus.
:Press to access the user-friendly menu system, as detailed below.
→F1:Calibrate →F1:Channel 1 ¬
F2:Channel 2 ¬
F3:Channel 3 ¬
F4:Temperature
→F2:Notepad →F1:Recall
F2:Erase →F1:Erase All
F2:Erase Last
F3:Print -
F4:Program →F1:Secs
F2:Mins
F3:Hours
→F3:Mode →F1:Channel 1 →F1:pH →F1: .1
F2: .01
F3: .001
F2:mV →F1:Absolute
F2:Relative
F3:Ion →See section 3
F2:Channel 2 →F1:pH →F1: .1
F2: .01
F3: .001
F2:mV →F1:Absolute
F2:Relative
F3:Ion →See section 3
F3:Channel 3 →F1:pH →F1: .1
F2: .01
F3: .001
F2:mV →F1:Absolute
F2:Relative
F3:Ion →See section 3
→F4:Setup →F1:Ports →F1:Baud Rate -
F2:Recorder ®
F2:Clock
F3:GLP →F1:Recall
F3:Print -
F4:Standards →F1:Channel 1
F2:Channel 2
F1:Channel 3
¬Only those Channels that are currently set to Ion or pH mode are offered for calibration.
-These functions available when RS232 Port option is fitted.
®This function available when Recorder Port option is fitted.

9
3. Specific Ion Mode
3.1 Selecting Specific Ion Mode
1. Select Specific Ion Mode for Channel 1, 2 or 3.
(e.g. →→ F3:ModeF3:Mode →→ F1:Channel 1F1:Channel 1 →→ F3:IonF3:Ion)
2. The Valency selection screen is now displayed…
VALENCY >F1:+Mono F2:-MonoVALENCY >F1:+Mono F2:-Mono
F3:++Di F4:--DiF3:++Di F4:--Di
The arrow indicates the current selection.
Press to select Monovalent Cation (e.g. Na+).
Press to select Monovalent Anion (e.g. F-).
Press to select Divalent Cation (e.g. Cu2+).
Press to select Divalent Anion (e.g. S2-).
Press to quit without changing the current setting.
3. The Units selection screen is now displayed…
UNITS >F1:ppM F2:ppKUNITS >F1:ppM F2:ppK
F3:% F4:ExponentialF3:% F4:Exponential
The arrow indicates the current selection.
Press to select readout in ppM (Parts Per Million).
Press to select readout in ppK (Parts Per Thousand).
Press to select readout in %.
Press to select readout in Exponential units (e.g. Molar).
Press to quit without changing the current setting.
4. The Ion Resolution screen is now displayed…
Ion Resolution F1:3 Digits F2:2 DigitsIon Resolution F1:3 Digits F2:2 Digits
>F3:Auto-Rounding>F3:Auto-Rounding
The arrow indicates the current selection.
Press to select resolution to 3 significant digits. In this mode, the readings may become
slightly noisy towards the end of each decade, due to the logarithmic nature of the sensor
signal.
Press to select resolution to 2 significant digits. Readings in this mode are very stable,
although 1 signficant digit is lost.
Press to select Auto-rounding. Readings in this mode are displayed to 3 signficant digits
for most of the decade, and automatically rounded for stability towards the end of the decade.
Auto-rounding is recommended for most users.
Press to quit without changing the current setting.

10
3.2 Setting Specific Ion Standards
The Primary and Secondary Specific Ion standards must be set before attempting Specific Ion
calibration.
The Primary and Secondary Specific Ion standard values are entered and stored separately for each
Channel.
The standards for a Channel must be re-entered when changing Specific Ion modes for that
Channel.
All Primary and Secondary Specific Ion standards must be re-entered if the 900-I3 is initialised.
3.2.1 Setting Specific ion standards for ppM, ppK and % readouts
1. Select the Specific Ion standards set-up menu for Channel 1, 2 or 3.
(e.g. →→ F4:SetupF4:Setup →→ F4:StandardsF4:Standards →→ F1:Channel 1F1:Channel 1).
2. The Primary Standard set-up screen will now be displayed.
Enter Primary Standard :Enter Primary Standard : 00.00 ppM.00 ppM
Type in the value of the Primary standard, including the decimal point. Use the key to
make any corrections.
Press to save the Primary standard.
Alternatively, press to quit without changing the current setting.
3. The Secondary Standard set-up screen is now displayed.
Enter Secondary Standard :Enter Secondary Standard : 00.00 ppM.00 ppM
Type in the value of the Secondary standard, including the decimal point. Use the key to
make any corrections.
The Secondary Standard must be at least 2 to 100 times higher or lower than the primary
standard.
Press to save the Secondary standard.
Alternatively, press to quit without changing the current setting.

11
3.2.2 Setting Specific ion standards for Exponential readout
1. Select the Specific Ion standards set-up menu for Channel 1, 2 or 3.
(e.g. →→ F4:SetupF4:Setup →→ F4:StandardsF4:Standards →→ F1:Channel 1F1:Channel 1).
2. The Primary Standard set-up screen will now be displayed.
Enter Primary Standard : 0.00Enter Primary Standard : 0.001010++0000
Readings in Exponential mode are expressed in Scientific notation. For example, 1.001.001010––0404
should be read as 1.00 x 10-4.
Type in 3 significant digits of the value of the Primary standard. The decimal point is fixed for
you in this mode.
Now press for 10+or press for 10–.
Enter the power. This can be entered as 1 or 2 digits (e.g. “0404” is treated the same as “44”).
Use the key to make any corrections.
Press to save the Primary standard.
Alternatively, press to quit without changing the current setting.
3. The Secondary Standard set-up screen will now be displayed.
Enter Secondary Standard : 0.00Enter Secondary Standard : 0.001010++0000
The Secondary Standard must be at least 2 to 100 times higher or lower than the primary
standard.
Type in 3 significant digits of the value of the Secondary standard. The decimal point is fixed
for you in this mode.
Now press for 10+or press for 10–.
Enter the power. This can be entered as 1 or 2 digits (e.g. “0404” is treated the same as “44”).
Use the key to make any corrections.
Press to save the Secondary standard.
Alternatively, press to quit without changing the current setting.

12
3.3 Specific Ion Calibration
1. Plug the Ion Selective Electrode into the Probe 1, Probe 2 or Probe 3 socket.
If a separate Reference Electrode is being used, plus this into the matching 4mm Ref 1, Ref 2
or Ref 3 socket provided.
Plug the Temperature sensor into the Temp. socket.
2. Switch the meter on.
3. Select and set up Ion mode, as detailed in section 3.1.
Set up the Primary and Secondary Specific Ion standards, as detailed in section 3.2.
For the purposes of this handbook, the 900-I3 has been set up for 100ppM as the Primary
Standard and 10.0ppM as the Secondary Standard.
4. Ensure that temperature has already been calibrated (section 7.1) or manually set (section 7.4).
NOTE: A “ ∗∗ ” in place of the decimal point in the temperature readout indicates that
temperature is not calibrated.
5. Remove the wetting caps from the Ion Selective and Reference electrodes, if fitted.
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 the Ion Selective Electrode sensing surface and the reference electrode’s reference
junction are both covered, as per the diagram below.
Add any Ionic Strength Adjusting Buffer (ISAB) that may be required (see the Ion Selective
Electrode’s handbook).
A magnetic stirrer providing constant, gentle stirring generally improves stability.
Continued over the page…

13
7. Select Primary Calibration for Channel 1, 2 or 3.
(e.g. →→ F1:CalibrateF1:Calibrate →→ F1:Channel 1F1:Channel 1 →→ F1:PrimaryF1:Primary).
The primary calibration screen is now displayed. The current reading is displayed on the top
left, followed by the actual mV data coming from the sensor. The message “Cal?Cal?” instead of
the reading indicates that the 900-I3 is currently not Primary calibrated. For example…
Cal? 0.1Cal? 0.1 25.025.0OOcc
Ion 100.ppM Calibration, Press EnterIon 100.ppM Calibration, Press Enter
When the mV reading has stabilised, press to calibrate to the Primary Standard value.
Press to quit without calibrating.
The 900-I3 will now display the Offset of the Ion Selective Electrode, before asking if you
wish to go on to a Secondary Calibration…
Press Enter to go on for Second StandardPress Enter to go on for Second Standard
Calibration {Slope}, or Menu to QuitCalibration {Slope}, or Menu to Quit
Note that the “ ∗∗ ” will not removed from the Specific Ion readout until a Secondary calibration
has been successfully performed
8. Rinse the Sensors in distilled water and blot dry.
Secondary Calibration
9. Place the Ion Selective, Reference and Temperature sensors into the Secondary Standard.
Ensure that the Ion Selective Electrode sensing surface and the reference electrode’s reference
junction are both covered, as per the diagram in step 6, above.
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 improves stability.
10. Select Secondary Calibration for the same Channel as selected in step 7, above.
(e.g. →→ F1:CalibrateF1:Calibrate →→ F1:Channel 1F1:Channel 1 →→ F3:SecondaryF3:Secondary).
The 900-I3 will have done this for you if you pressed at the end of step 7.
The secondary calibration screen is now displayed. The current reading is displayed on the top
left, followed by the actual mV data coming from the sensor. A “ ∗∗ ” in place of the decimal
point indicates that the 900-I3 is currently not Secondary calibrated. For example…
11*0ppM 56.7mV 25.011*0ppM 56.7mV 25.0OOcc
Ion 10.0ppM Calibration, Press EnterIon 10.0ppM Calibration, Press Enter
When the mV reading has stabilised, press to calibrate to the Secondary Standard
value.
Press to quit without calibrating.
The 900-I3 will now display the Slope of the Ion Selective Electrode.
A “ ∗∗ ” in the display will be replaced by a decimal point after a successful 2-point Slope
calibration, for the Channel that was calibrated.
11. The 900-I3 is now ready for Specific Ion measurements for the Channel that was calibrated.
Rinse the Ion Selective, Reference and Temperature sensors in distilled water and blot dry
before placing them into unknown samples.

14
3.4 Specific Ion Calibration Notes
1. A Primary Calibration should be performed at least weekly. In applications where the reference
electrode junction can become blocked, such as dairy products, mining slurries etc, a Primary
Calibration may have to be done daily.
2. A full Primary and Secondary Calibration should be performed at least monthly. Of course,
more frequent calibration will result in greater confidence in results.
3. Calibration information for each Channel is retained in memory when the 900-I3 is switched
off, even when the power supply is removed. This information can be recalled or printed later
using the GLP function (see section 8).
4. The 900-I3 displays the value of the standard to which it will attempt to calibrate. Ensure that
the standard value displayed corresponds to the standard that you are using. Alter the Standards
set-up if necessary (see section 3.2).
3.5 Specific Ion Calibration Messages
1. If a Primary Calibration has been successfully performed, the 900-I3 will display the following
message, and the Offset value of the sensor. For example…
100100∗∗ppM 25.0ppM 25.0OOcc
Calibration OK. mV @ STD1=0.1mVCalibration OK. mV @ STD1=0.1mV
2. If a Secondary Calibration has been successfully performed, the 900-I3 will display the
following message, and the slope value of the sensor. For example…
10.0ppM 56.7mV 25.010.0ppM 56.7mV 25.0OOcc
Calibration OK. Slope=95.6%Calibration OK. Slope=95.6%
3. If a Secondary Calibration has failed, the 900-I3 will display the following message, and the
failed slope value of the electrode. For example…
3535∗∗2ppM 25.4mV 25.02ppM 25.4mV 25.0OOcc
Calibration Failed. Slope=42%Calibration Failed. Slope=42%
Notes
1. The 900-I3 has an unlimited Offset range, as long as the reading is not over-ranged.
This is to allow for the large variety of Ion Selective Electrodes available.
2. The allowable Slope range is 50.0 to 110.0 %. This range is ample to allow for correctly
functioning Ion Selective Electrodes. If calibration fails due to the Slope being outside these
limits, then please consult the Troubleshooting guide (section 16.2) for possible remedies.

15
4. pH Mode
4.1 Selecting pH Mode
1. Select pH Mode for Channel 1, 2 or 3.
(e.g. →→ F3:ModeF3:Mode →→ F1:Channel 1F1:Channel 1 →→ F1:pHF1:pH).
2. The pH Resolution screen is now displayed…
Select pH ResolutionSelect pH Resolution
F1:0.1 >F2:0.01 F3:0.001F1:0.1 >F2:0.01 F3:0.001
The arrow indicates the current selection.
Press to select 0.1 pH resolution.
Press to select 0.01 pH resolution.
Press to select 0.001 pH resolution.
Press to quit without changing the current selection.

16
4.2 Setting the pH Buffer Set
The 900-I3 can be programmed to automatically recognise any of the following buffer sets during
pH calibration. All pH values listed below are at 20 OC.
1. pH4.00, pH6.88, pH9.22
2. pH4.00, pH6.88, pH10.06
3. pH4.00, pH7.00, pH9.22
4. pH4.00, pH7.00, pH10.06.
To select the pH buffer set for automatic recognition…
1. Switch the 900-I3 OFF.
2. Press and HOLD the key while turning the 900-I3 back on.
3. The primary buffer selection menu is now displayed…
Select Primary BufferSelect Primary Buffer
→→F1:6.88pH F2:7.00pHF1:6.88pH F2:7.00pH
The arrow indicates the current selection.
Press to select pH6.88 as the Primary Buffer.
Press to select pH7.00 as the Primary Buffer.
Press to quit without changing the current setting.
4. The secondary buffers selection menu is now displayed…
Select Secondary BuffersSelect Secondary Buffers
>F1:4.00/9.22pH F2:4.00/10.06pH>F1:4.00/9.22pH F2:4.00/10.06pH
The arrow indicates the current selection.
Press to select pH4.00 and pH9.22 as the Secondary Buffers.
Press to select pH4.00 and pH10.06 as the Secondary Buffers.
Press to quit without changing the current setting.
Notes
1. The selected buffer set will the same for all Channels that are set to pH mode.
2. The selected buffer set is kept in memory when the meter is switched off.
3. The buffers are re-set to pH4.00, pH6.88 and pH9.23 during initialisation.
4. pH6.88 buffer is a DIN 19266 and NBS Primary-standard pH solution. Its use as the primary
buffer is highly recommended for the most accurate possible results. If pH7.00 buffer is used,
ensure that it is manufactured to at least 0.01pH accuracy. pH7.00 buffer has a buffer capacity
less than half that of pH6.88 buffer and is therefore much less stable.
5. pH9.23 and pH10.01 buffers are highly unstable. Avoid using these buffers if possible. Discard
immediately after use.
6. If you wish to use a pH buffer other than one of those listed above, its value can be keyed in
during calibration. Make sure that you have pH versus Temperature data for the buffer.

17
4.3 pH Calibration
1. Plug the pH sensor into the Probe 1, Probe 2 or Probe 3 socket and the temperature sensor
into the Temp. socket. Switch the meter on.
2. Select pH Mode and the desired pH resolution (see section 4.1).
3. Ensure that temperature has already been calibrated, or manually set (see sections 7.1 and 7.4).
NOTE: If the decimal point in the temperature reading is shown by a “ ∗∗ ”, then the
temperature readout is not calibrated.
4. Remove the wetting cap from the pH sensor. Rinse the pH and Temperature sensors in distilled
water and blot them dry.
5. Ensure that the primary and secondary buffers to be used have been correctly selected for
automatic buffer recognition. See section 4.2.
6. Place both electrodes into a small sample of primary buffer (pH6.88 or 7.00), so that the bulb
and reference junction are both covered, as per the diagram below.
DO NOT place the electrodes directly into the buffer bottle.
7. Select pH Calibration for Channel 1, 2 or 3.
(e.g. →→ F1:CalibrateF1:Calibrate →→ F1:Channel 1F1:Channel 1 →→ F1:pHF1:pH).
The display should now look something like this…
6*85pH Buffer=6*85pH Buffer=66.86 25.0.86 25.0OOcc
Press ENTER to Calibrate, or Edit Buffer.Press ENTER to Calibrate, or Edit Buffer.
The current pH reading is shown on the left. Note the “ ∗∗ ”, indicating that pH is currently not
calibrated. Wait for this reading to stabilise before attempting to calibrate the 900-I3.
The buffer that the 900-I3 has attempted to recognise is also displayed with the correct value at
the current temperature.
Press to calibrate to the displayed buffer.
Otherwise, enter an alternative buffer using the Numeric Keypad, and then press .
If a 1 point calibration has been performed, the “ ∗∗ ” will not be removed until a full 2 point
calibration has been performed.

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8. Rinse the pH and Temperature sensors in distilled water and blot them dry.
9. Place both sensors into a small sample of secondary buffer (pH4.00, 9.23 or 10.01), so that the
bulb and reference junction are both covered, as per the diagram in step 6, above.
DO NOT place the electrodes directly into the buffer bottle.
NOTE: pH9.23 and pH10.01 buffers are highly unstable. Avoid using these buffers if
possible. Discard immediately after use.
10. Select pH Calibration for the same Channel as selected in step 7, above.
(e.g. →→ F1:CalibrateF1:Calibrate →→ F1:Channel 1F1:Channel 1 →→ F1:pHF1:pH).
The display should now look similar to the example shown in step 7. Note that the 900-I3 has
automatically recognised the second buffer.
Wait for the displayed reading to stabilise before attempting to calibrate the 900-I3.
Press to calibrate to the displayed buffer.
Otherwise, enter an alternative buffer using the Numeric Keypad, and then press .
11. The 900-I3 is now ready for pH measurements for the Channel that was calibrated. Discard the
used samples of buffer.
Rinse the pH and Temperature sensors in distilled water and blot them dry before placing them
into unknown samples.
4.4 pH Calibration Notes
1. A 1-point calibration should be performed at least weekly. In applications where the electrode
junction can become blocked, such as dairy products, mining slurries etc, a 1-point calibration
may have to be done daily.
2. A full 2-point calibration should be performed at least monthly. Of course, more frequent
calibration will result in greater confidence in results.
3. Calibration information for each Channel is retained in memory when the 900-I3 is switched
off, even when the power supply is removed. This information can be recalled or printed later
using the GLP function (see section 8).

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4.5 pH Calibration Messages
1. If a 1-point calibration has been successfully performed, the 900-I3 will display the following
message, and the asymmetry of the electrode. Note that the slope value from the last calibration
is also shown.
Asymmetry Calibration SuccessfulAsymmetry Calibration Successful
+0.10pH Asym 100% Slope+0.10pH Asym 100% Slope
2. If a 1-point calibration has failed, the 900-I3 will display the following message, and the failed
asymmetry value of the electrode.
Calibrate Failed, +1.2 pH AsymmetryCalibrate Failed, +1.2 pH Asymmetry
Repeat Cal. or Initialize CalibrationRepeat Cal. or Initialize Calibration
3. If a 2-point calibration has been successfully performed, the 900-I3 will display the following
message, and the asymmetry and slope of the electrode.
Slope & Asymmetry Calibration SuccessfulSlope & Asymmetry Calibration Successful
+0.10pH Asym 99.0% Slope+0.10pH Asym 99.0% Slope
4. If a 2-point calibration has failed, the 900-I3 will display the following message, and the failed
slope value of the electrode.
Calibrate Failed, 80% SlopeCalibrate Failed, 80% Slope
Repeat Cal. or Initialize CalibrationRepeat Cal. or Initialize Calibration
5. The 900-I3 has an allowable Asymmetry range of –1.00 to +1.00 pH. The allowable Slope
range is 85.0 to 105.0 %. If calibration fails due to either the Asymmetry or the Slope being
outside these limits, then please consult the Troubleshooting guide (section 16.2) for possible
remedies.

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5. Absolute Millivolt Mode
5.1 Selecting Absolute Millivolt Mode
Select absolute mV mode for Channel 1, 2 or 3.
(e.g. →→ F3:ModeF3:Mode →→ F1:Channel 1F1:Channel 1 →→ F2:mVF2:mV →→ F1:AbsoluteF1:Absolute)
The 900-I3 will display the actual millivolts produced by the sensor in this mode.
5.2 Absolute Millivolt Calibration
The millivolt section of the 900-I3 is factory calibrated. There is no user-calibration facility for this
mode.
Temperature compensation is not applicable in Millivolt mode.