TPS 90-FL User manual

Congratulations !
The 90-FL is complete water quality logger in a single portable unit. It combines Dissolved
Oxygen, Conductivity, TDS, pH and Temperature.
Despite its impressive list of features, the 90-FL 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 90-FL. 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 90-FL, 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.tps.com.au
90-FL
Dissolved Oxygen,
Conductivity, TDS, pH,
Temperature Logger
Date :01-Feb-2001
Author :MS
Version :6.0

1
Contents
1. Introduction .......................................................................................................................................3
1.1 90-FL Display and Controls.............................................................................................................3
1.2 90-FL Rear Panel Connectors..........................................................................................................3
1.3 Menu and Function Keys.................................................................................................................4
1.4 Numeric Keys..................................................................................................................................4
1.5 Enter Key........................................................................................................................................4
1.6 Delete Key ...................................................................................................................................... 4
1.7 ON and OFF Keys...........................................................................................................................4
1.8 80 Character Display.......................................................................................................................4
1.9 Unpacking Information.................................................................................................................... 5
1.10 Specifications..............................................................................................................................6
2. 90-FL Menu Structure........................................................................................................................ 9
3. Dissolved Oxygen Mode.................................................................................................................. 10
3.1 Selecting Dissolved Oxygen Mode ................................................................................................ 10
3.2 Dissolved Oxygen Calibration ....................................................................................................... 10
3.3 Dissolved Oxygen Calibration Notes ............................................................................................. 13
3.4 Dissolved Oxygen Calibration Messages ....................................................................................... 13
3.5 Dissolved Oxygen Stirrer............................................................................................................... 14
4. Conductivity Mode........................................................................................................................... 15
4.1 Selecting Conductivity Mode......................................................................................................... 15
4.2 Setting the Conductivity calibration standard................................................................................. 15
4.3 Setting the Conductivity sensor k factor......................................................................................... 16
4.4 Conductivity Calibration................................................................................................................ 17
4.5 Conductivity Calibration Notes...................................................................................................... 18
4.6 Conductivity Calibration Messages................................................................................................ 18
5. TDS Mode......................................................................................................................................... 19
5.1 Selecting TDS Mode ..................................................................................................................... 19
5.2 Setting the TDS calibration standard.............................................................................................. 19
5.3 Setting the TDS sensor k factor...................................................................................................... 20
5.4 TDS Calibration ............................................................................................................................ 21
5.5 TDS Calibration Notes .................................................................................................................. 22
5.6 TDS Calibration Messages............................................................................................................. 22
6. pH Mode........................................................................................................................................... 23
6.1 Selecting the pH Buffer Set ........................................................................................................... 23
6.2 pH Calibration............................................................................................................................... 24
6.3 pH Calibration Notes..................................................................................................................... 25
6.4 pH Calibration Messages............................................................................................................... 26
7. Temperature Mode........................................................................................................................... 27
7.1 Temperature Calibration................................................................................................................ 27
7.2 Temperature Calibration Notes...................................................................................................... 28
7.3 Calibration Messages..................................................................................................................... 28
7.4 Manual Temperature Setting.......................................................................................................... 29
8. Good Laboratory Practices (GLP)................................................................................................... 30
8.1 To recall GLP information on the display ...................................................................................... 30
8.2 Failed Calibration.......................................................................................................................... 32
8.3 Printing GLP Information to the RS232 Port.................................................................................. 32
8.4 Instrument Serial Number.............................................................................................................. 33
8.5 Additional GLP Features............................................................................................................... 33

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9. Datalogging...................................................................................................................................... 34
9.1 Setting the A & B Data Input Function .......................................................................................... 34
9.2 Manually Recording Readings into the Logger............................................................................... 34
9.3 Automatic Datalogging.................................................................................................................. 37
9.4 Recalling Readings from the Logger.............................................................................................. 41
9.5 Erasing Records from the Logger................................................................................................... 42
9.6 Printing Records from the Logger to the RS232 Port...................................................................... 42
10. RS232 Port....................................................................................................................................... 43
10.1 Setting the Baud Rate................................................................................................................ 43
10.2 Sending Readings to the RS232 Port ......................................................................................... 43
10.3 RS232 Configuration................................................................................................................. 43
10.4 Communication and Statistical Software.................................................................................... 43
10.5 Commands................................................................................................................................ 43
10.6 Data Format .............................................................................................................................. 45
10.7 GLP Data Format...................................................................................................................... 46
10.8 Importing Data into Microsoft Excel.......................................................................................... 47
11. Setting the Clock ............................................................................................................................. 49
12. Initialising the 90-FL........................................................................................................................ 50
13. Instrument firmware version number ............................................................................................. 50
14. Battery Saver Function.................................................................................................................... 51
15. Moisture Protection......................................................................................................................... 52
15.1 Silica Gel Pack.......................................................................................................................... 52
15.2 Corrosion Inhibitor Tab............................................................................................................. 52
16. Troubleshooting .............................................................................................................................. 53
16.1 General Errors........................................................................................................................... 53
16.2 Dissolved Oxygen Troubleshooting........................................................................................... 54
16.3 Conductivity / TDS Troubleshooting......................................................................................... 55
16.4 pH Troubleshooting................................................................................................................... 56
16.5 Temperature Troubleshooting.................................................................................................... 57
17. Appendices...................................................................................................................................... 58
17.1 Dissolved Oxygen..................................................................................................................... 58
17.2 Conductivity/TDS..................................................................................................................... 61
17.3 pH............................................................................................................................................. 63
18. Warranty........................................................................................................................................... 67

3
1. Introduction
1.1 90-FL Display and Controls
1.2 90-FL Rear Panel Connectors

4
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 Logger. See section 9.
:Press to start and stop the optional Dissolved Oxygen stirrer. See section 3.5.
:Press to transmit current reading plus date and time to the RS232 port. See section 10.2.
:Press to start automatic datalogging in the Sampling Period and Duration mode. See section
9.3.3.
:Press to obtain context-sensitive help messages. This function is disabled within menus.
1.4 Numeric Keys
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.
1.7 ON and OFF Keys
Press the relevant key to switch the 90-FL on and off as required.
1.8 80 Character Display
80 character alphanumeric display with user-friendly menu and context-sensitive help system.
Shows Dissolved Oxygen, Conductivity/TDS, pH, Temperature, Date and Time simultaneously.

5
1.9 Unpacking Information
Before using your new 90-FL, please check that the following accessories have been included:
Part No
Standard Kit…
1. 90-FL Field Lab.....................................................126103
2. pH6.88 Buffer, 200mL...........................................121306
3. pH4.00 Buffer, 200mL...........................................121381
4. 2.76 mS/cm Conductivity Standard, 1 Litre............ 122305
5. Plug-Pack Power Supply........................................ 130009
6. 90-FL Handbook................................................... 130050
Sensors…
1. YSI Field type DO2sensor.....................................123204
2. 3m Cable for YSI Field DO2sensor .......................123215
3. 5m Cable for YSI Field DO2sensor .......................123219
4. 7.5m Cable for YSI Field DO2sensor ....................123216
5. 15m Cable for YSI Field DO2sensor .....................123217
6. YSI Non-stirring DO2sensor for BOD bottles........123214
7. YSI Self-stirring DO2sensor for BOD bottles ........123213
8. k=10/ATC/Temp Conductivity Sensor, 5m ............122218
9. k=1/ATC/Temp Conductivity Sensor, 5m.............. 122196
10. Submersible pH Sensor, Gel Filled, 5m..................111224
11. Intermediate Junction pH Sensor, 5m..................... 111227
12. Temperature Sensor, 5m ........................................124210
(not required when Conductivity sensor is in use)
Options…
1. PVC Sensor holder assembly, 5m s/s cable ............121343
2. Dissolved Oxygen stirrer, 5m.................................123306
3. Extended cable for sensors (order by the metre).....130040
4. RS232 Serial Interface Cable .................................130015
5. Communication software for Windows 3.1, ........... 130086
95, 98 and NT
6. Solar Panel.............................................................130012
7. Clip lead for external 12V DC battery....................130013
8. Hard Carry case for meter and accessories .............130058
Spares…
1. 7.2V NiCad Battery Pack.......................................130027
2. Senson®VapaguardTab corrosion inhibitor........NRP2
3. Membrane, Filling Solution and Zero DO2kit........123300

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1.10 Specifications
1.10.1 Dissolved Oxygen
Range Resolution Accuracy
0 to 32.00 ppM 0.01 ppM ±0.2% of full scale
0 to 320.0 % Saturation 0.1 % Saturation ±0.3 % Saturation
0 to 66.0 % Gaseous 0.1 % Gaseous ±0.1 % Gaseous
Note : Full scales are subject to sensor performance.
Sensor Type...........................................Clark type polarographic sensor with in-built ATC.
Salinity Correction for ppM.................0 to 50.0 ppK, automatic using conductivity/TDS reading.
Temperature Compensation.................Automatic for membrane permeability.
Automatic for Dissolved Oxygen solubility in ppM mode.
Calibration............................................Automatic zero and span calibration.
Sensor Span Range ...............................65 to 200 %
1.10.2 Conductivity
Ranges Resolution Accuracy
k=0.1 Sensor
0 to 2.000 µS/cm
0 to 20.00 µS/cm
0 to 200.0 µS/cm
0 to 2000 µS/cm
0.001 µS/cm
0.01 µS/cm
0.1 µS/cm
1 µS/cm
±0.5% of full scale of
selected range at 25 OC
k=1.0 Sensor
0 to 20.00 µS/cm
0 to 200.0 µS/cm
0 to 2000 µS/cm
0 to 20.00 mS/cm
0.01 µS/cm
0.1 µS/cm
1 µS/cm
0.01 mS/cm
±0.5% of full scale of
selected range at 25 OC
k=10 Sensor
0 to 200.0 µS/cm
0 to 2000 µS/cm
0 to 20.00 mS/cm
0 to 200.0 mS/cm
0.1 µS/cm
1 µS/cm
0.01 mS/cm
0.1 mS/cm
±0.5% of full scale of
selected range at 25 OC
Note : Ranges are automatically selected. Exact auto-ranging points and full scales are subject to
sensor performance.
Sensor Type...........................................Ryton®plastic body with two platinised platinum plates
with in-built ATC.
Temperature Compensation.................Automatic, 0 to 100 OC
(standard Conductivity sensor is limited to 60 OC)
Calibration............................................Automatic zero and span calibration
Sensor Span Range ...............................±25% of nominal k factor

7
1.10.3 TDS
Ranges Resolution Accuracy
k=0.1 Sensor
0 to 1.000 ppM
0 to 10.00 ppM
0 to 100.0 ppM
0 to 1000 ppM
0.001 ppM
0.01 ppM
0.1 ppM
1 ppM
±0.5% of full scale of
selected range at 25 OC
k=1.0 Sensor
0 to 10.00 ppM
0 to 100.0 ppM
0 to 1000 ppM
0 to 10.00 ppK
0.01 ppM
0.1 ppM
1 ppM
0.01 ppK
±0.5% of full scale of
selected range at 25 OC
k=10 Sensor
0 to 100.0 ppM
0 to 1000 ppM
0 to 10.00 ppK
0 to 100.0 ppK
0.1 ppM
1 ppM
0.01 ppK
0.1 ppK
±0.5% of full scale of
selected range at 25 OC
Note : Ranges are automatically selected. Exact auto-ranging points and full scales are subject to
sensor performance.
Sensor Type...........................................Ryton®plastic body with two platinised platinum plates
with in-built ATC.
Temperature Compensation.................Automatic, 0 to 100 OC
(standard Conductivity sensor is limited to 60 OC)
Calibration............................................Automatic zero and span calibration.
Sensor Span Range ...............................±25% of nominal k factor.
1.10.4 pH
Range Resolution Accuracy
0 to 14.00 pH 0.01 pH ±0.01 pH
Sensor Type...........................................Glass bulb pH sensor, combination or half cell.
Input Impedance...................................>3 x 1012 Ohms
Temperature Compensation.................Automatic, 0 to 100 OC
Calibration............................................Automatic asymmetry and slope calibration.
Automatic Buffer Recognition..............pH4.00, pH6.88, pH7.00, pH9.23 & pH10.06.
Any other can be entered during calibration.
Sensor Asymmetry Range ....................-1.00 to 1.00 pH
Sensor Slope Range...............................85.0 to 105.0 %

8
1.10.5 Temperature
Range Resolution Accuracy
-30.0 to 110.0 OC 0.1 OC ±0.2 OC
Note : When using Conductivity/TDS sensor for Temperature readout, sensor is limited to 60 OC.
Sensor Type...........................................Silicon transistor built into tip of Conductivity/TDS
sensor, or separate Temperature sensor if Conductivity /
TDS sensor is not in use.
Calibration............................................Automatic offset and span calibration
Sensor Offset Range..............................-15.0 to 15.0 OC
Sensor Span Range ...............................93 to 107 %
1.10.6 General Specifications
Memory.................................................2032 readings including date and time with A&B function
disabled.
1632 readings including date and time with A&B function
enabled.
Automatic Logging ...............................Rate per Day
1 to 288 readings per day.
Time of Day
1 to 12 discrete times of the day, in 24 hour format.
Sampling Period and Duration
One reading every 1 to 300 seconds for a duration of 1 to
720 minutes or continuous.
RS232 Port ............................................300, 9600 & 19200 baud.
8 bits, no parity, 1 stop bit, XON/XOFF Protocol.
Clock......................................................Calendar clock displays date, month, hours, minutes &
seconds. Year is Y2K compliant and is attached to all
stored data.
Good Laboratory Practices ..................Date, time and results of last calibration for all parameters
are stored. This information can be recalled or sent to the
RS232 port at any time.
Power.....................................................7.2V, 1300mAH NiCad battery built in.
Battery charger for country of destination is included.
Solar panel and external battery clip lead optionally
available.
Battery Saver ........................................Auto switch-off after 5 minutes or 1 hour. Battery saver
can be switched off to allow continuous use.
Dimensions............................................230 x 140 x 100 mm
Mass.......................................................Instrument only :Approx. 1.5 kg
Full Kit :Approx. 5.0 kg
Environment .........................................Temperature :0 to 45 OC
Humidity :0 to 90 % R.H.

9
2. 90-FL Menu Structure
A detailed breakdown of the menu system of the 90-FL is shown below. This diagram provides a
quick reference for the menu functions available for the 90-FL.
→F1:Calibrate →F1:Oxygen
F2:Conductivity
or: F2:TDS
F3:pH
F4:Temperature
→F2:Mode →F1:Oxygen →F1:ppm
F2:ppM (Sal)
F3:%Sat
F4:%Gas
F3:Conductivity
F4:TDS
→F3:Logger →F1:Recall
F2:Erase →F1:Erase All
F2:Erase Last
F3:Print Log
F4:Start
or: F4:Stop
F5:Program →F1:Rate per Day
F2:Time of Day
F3:Sampling Period
and Duration
→F4:Setup →F1:Standards →F1:Conductivity
F2:TDS
F3:pH Buffers
F2:GLP →F1:Recall
F3:Print
F4:Initialise Meter
F3:Set AB →F1:A=Pond,No B
F2:A=Pond,B=Data
F3:A=Data,NoB
F4:A&B=Data
F5:OFF
F4:k factor * →F1:k=.1 *
F2:k=1 *
F5:System →F1:Bat. Saver →F1:OFF
F2:5 minutes
F3:1 hour
F2:Set Clock
F3:Baud Rate →F1:300
F2:9600
F3:19200
F4:Stirrer Enable
or: F4:Stirrer Disable
* This function not available when a TPS k=10 sensor is connected.

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3. Dissolved Oxygen Mode
3.1 Selecting Dissolved Oxygen Mode
1. Select Dissolved Mode ( →→ F2:Mode →→ F1:Oxygen).
2. The Dissolved Oxygen readout units selection screen is now displayed…
MODE F1:ppm F2:ppM (Sal)
>F3:% Sat F4:% Gas
The arrow indicates the current selection.
Press to select Dissolved Oxygen readout in ppm units. This selection will not apply
Salinity correction to the displayed readings.
Press to select Dissolved Oxygen readout in Salinity-corrected ppM units. This selection
will use the Conductivity or TDS reading for automatic salinity correction.
Press to select Dissolved Oxygen readout in % Saturation units.
Press to select Dissolved Oxygen readout in % Gaseous units.
Press to quit without changing the current setting.
3.2 Dissolved Oxygen Calibration
1. Plug the Dissolved Oxygen sensor into the Oxygen socket.
2. Switch the meter on.
3. Select the Dissolved Oxygen readout mode to be used, as detailed in section 3.1.
4. Ensure that the Temperature readout has been calibrated (see section 7.1) or manually set (see
section 7.4) when calibrating either of the ppM modes..
5. Rinse the Dissolved Oxygen sensor in distilled water and blot dry.
3.2.1 Zero Calibration (all Oxygen modes)
1. Place the Dissolved Oxygen sensor into an oxygen-free solution. This solution may be prepared
by dissolving 2g of Sodium Sulphite in 100mL of distilled water. A 50g bottle of Sodium
Sulphite powder (part number 123302) is supplied with a new Dissolved Oxygen sensor or
Membrane Kit for this purpose.
2. Allow the reading to stabilise at or near zero. This may take 2-3 minutes.
3. Select Oxygen Calibration. ( →→ F1:Calibrate →→ F1:Oxygen)
When the reading is below approximately 25 % Saturation, 2 ppM or 5% Gaseous, the
90-FL will display the ZERO calibration screen…
1*0%Sat 25.0oc
Oxygen ZERO Calibration, Press Enter
4. Press to calibrate.
A “∗” will not be removed from the display after a Zero Calibration.
5. Remove the sensor from the Zero solution, rinse well in distilled water and blot dry.
The 90-FL will now prompt you to perform an AIR calibration.

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3.2.2 Span Calibration in Air (all Oxygen modes)
1. Hang the Dissolved Oxygen sensor in air. The tip of the Dissolved Oxygen sensor should be
pointing downwards.
Allow the reading to stabilise. After a zero calibration, this may take up to 5 minutes.
2. Select Oxygen Calibration. ( →→ F1:Calibrate →→ F1:Oxygen)
When the reading is above approximately 25% Saturation, 2 ppM or 5% Gaseous, the
90-FL will display the AIR calibration screen…
101.0%Sat 25.0oc
Oxygen AIR Calibration, Press Enter
Press to calibrate.
A “∗” in the display will be replaced by a decimal point after a successful air calibration.
3. The 90-FL is now calibrated and is ready for Dissolved Oxygen measurements. Rinse the
Dissolved Oxygen sensor in distilled water and blot dry before placing it into unknown
samples.

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3.2.3 Span Calibration in Solution (Salinity-corrected ppM Mode only)
This span calibration provides an alternative to calibrating the Dissolved Oxygen sensor in air. It is
only available when the 90-FL is in Salinity-corrected ppM mode. Please note that the normal AIR
calibration (section 3.2.2) is still available for Salinity-corrected ppM mode.
1. Measure the Dissolved Oxygen content of the solution to be used for calibration. This is
generally done with a Winkler titration. The 90-FL span calibration should be performed
immediately the Dissolved Oxygen content of the solution is known, as the value may not be
stable.
2. Place the Dissolved Oxygen and Conductivity/TDS sensors into the calibration solution. Ensure
that the Conductivity/TDS sensor is calibrated and is correctly immersed (see sections 4.4 and
5.4).
The solution must be stirred at a moderate rate.
Allow the reading to stabilise. After a zero calibration, this may take up to 5 minutes.
3. Select Oxygen Calibration. ( →→ F1:Calibrate →→ F1:Oxygen)
When the reading is above approximately 2 ppM, the 90-FL will display the AIR/SPAN
calibration screen. Note the cursor underlining the “A” in “Air”.
9.10ppM 25.0oc
Oxygen AIR/SPAN Calibration, Press Enter
Use the numeric keypad to enter the Dissolved Oxygen value of the solution. The words
“AIR/SPAN” are deleted and the value being entered is displayed. The Conductivity or TDS
reading also appears as soon as the first numeric key is pressed.
Press the to correct any errors.
Ensure that the Dissolved Oxygen, Conductivity/TDS and Temperature readings are fully
stable.
Press to calibrate.
A “∗” in the display will be replaced by a decimal point after a successful air calibration.
4. The 90-FL is now calibrated and is ready for Dissolved Oxygen measurements. Rinse the
Dissolved Oxygen sensor in distilled water and blot dry before placing it into unknown
samples.

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3.3 Dissolved Oxygen Calibration Notes
1. The relationship of % Saturation and ppM depends on a number of variables, so always
calibrate in the mode required. Do not try to infer Oxygen content from one mode to another.
2. A zero calibration should be performed at least monthly. In applications where there is a low
level of dissolved oxygen, a zero calibration may have to be done weekly.
3. An air calibration should be performed at least weekly. Of course, more frequent calibration
will result in greater confidence in results.
4. All calibration information is retained in memory when the 90-FL is switched off. This
information can be recalled or printed later using the GLP function (see section 8).
3.4 Dissolved Oxygen Calibration Messages
1. If a Zero calibration has been successfully performed, the 90-FL will display the following
message and the Zero value of the sensor…
0.0%Sat 25.0oc
Calibration OK, Zero=0.5%
2. If a Zero calibration has failed, the 90-FL will display the following message and the failed
Zero value of the sensor. The unit will return to normal display mode with a “ ∗∗ ” in place of
the decimal point in the Dissolved Oxygen reading.
15.0%Sat 25.0oc
Calibration Failed, Zero=15.0%
3. If an Air/Span calibration has been successfully performed, the 90-FL will display the
following message and the Span value of the sensor…
100.0%Sat 25.0oc
Calibration OK, Span=100.0%
4. If an Air/Span calibration has failed, the 90-FL will display the following message and the
failed Span value of the sensor. The decimal point will be replaced by a “ ∗∗ ” when the unit
returns to normal display mode.
205.0%Sat 25.0oc
Calibration Failed, Span=205.0%
5. The allowable Span range for a Dissolved Oxygen sensor is 65.0 to 200.0 %. If calibration fails
due to the Span value being outside these limits, then please consult the Troubleshooting guide
(section 16.2) for possible remedies.

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3.5 Dissolved Oxygen Stirrer
The 90-FL is equipped with a 4.5V DC output to power a stirrer for the Dissolved Oxygen sensor.
This power output is suitable for the TPS submersible DO2stirrer (part number 123306).
3.5.1 Enabling and Disabling the Dissolved Oxygen stirrer output
1. Select the System menu ( →→ F5:System).
2. Select F4:Stirrer Enable or F4:Stirrer Disable from the menu as required.
3.5.2 Connecting the Dissolved Oxygen stirrer
To connect the Dissolved Oxygen stirrer…
1. Plug the Dissolved Oxygen stirrer into the Oxygen socket on the meter.
2. Plug the Dissolved Oxygen sensor into the in-line socket that is provided on the stirrer cable.
Please refer to the diagram below.
3.5.3 Starting and Stopping the Dissolved Oxygen stirrer
1. Ensure that the Dissolved Oxygen stirrer output has been enabled, as per section 3.5.1.
2. Press once in normal display mode to start the stirrer. The stirrer will stay on for 40
seconds and then stop. A countdown is provided on the screen.
3. Press a second time any time during the 40 second period to set the Dissolved Oxygen
stirrer to operate continuously.
4. Press a third time to stop the Dissolved Oxygen stirrer.
The Dissolved Oxygen stirrer starts and stops automatically when the 90-FL is in Rate per Day or
Time of Day automatic datalogging mode. See sections 9.3.1 and 9.3.2.

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4. Conductivity Mode
4.1 Selecting Conductivity Mode
1. Select Conductivity Mode ( →→ F2:Mode →→ F3:Conductivity).
2. The 90-FL now proceeds to Conductivity measurement mode. Note that a “ ∗∗ ” is shown in
place of the decimal point until a successful calibration has been performed (see section 4.4).
4.2 Setting the Conductivity calibration standard
The factory default for this item is 2.76mS/cm. If this is satisfactory, go directly to section 4.3.
1. Select the Conductivity Standard entry
(→→ F4:Setup →→ F1:Standards →→ F1:Conductivity).
The following screen is now displayed…
Conductivity Standard:2760 uS
Range 20uS/cm to 2000mS/cm
2. Type in the value of the Conductivity standard that is to be used for calibration, including the
decimal point. Use the key to make any corrections.
3. Press to save the value of the standard solution.
Alternatively, press to quit without changing the current setting.
4. The 90-FL will now ask you to enter the units for the Conductivity standard…
Conductivity Standard:2760
Select Units F1:uS/cm F2:mS/cm
Press to set the Conductivity Standard as µS/cm.
Press to set the Conductivity Standard as mS/cm.
5. The Conductivity standard is now programmed for use at calibration.

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4.3 Setting the Conductivity sensor k factor
The 90-FL automatically recognises a k=10 sensor. If a k=10 sensor is being used, go directly to
section 4.4.
The 90-FL does not automatically recognise k=0.1 or k=1 sensors. When a k=0.1 or k=1 sensor is
used, the 90-FL must be set to the correct k factor before use.
To select a k=0.1 or k=1 sensor…
1. Select k factor entry ( →→ F4:Setup →→ F4:k factor).
2. The k factor entry screen is now displayed…
Select nominal k factor,
F1:k=.1 >F2:k=1
The arrow indicates the current selection.
Press if a k=0.1 sensor is being used.
Press if a k=1 sensor is being used.
Press to quit without changing the current setting.
Notes
1. The manual k factor selection is kept in memory when the meter is switched off.
2. The manual k factor selection is reset to k=1 during initialisation.
3. The 90-FL will always automatically recognise a k=10 sensor, regardless of the manual k
factor selection.
4. Calibration settings for k=0.1, k=1 and k=10 sensors are NOT stored separately.
The 90-FL requires re-calibration when a new k factor sensor is connected.

17
4.4 Conductivity Calibration
Before attempting a Conductivity calibration, ensure that the 90-FL has been set up correctly
according to sections 4.1 to 4.3.
1. Plug the Conductivity sensor into the Cond/Sal socket.
2. Rinse the Conductivity sensor in distilled water. Shake off as much water as possible. Blot the
outside of the sensor dry. DO NOT BLOT THE ELECTRODE WIRES.
Zero Calibration
3. Let the sensor dry in air.
4. Select Conductivity Calibration ( →→ F1:Calibrate →→ F2:Conductivity).
5. The 90-FL will recognise the low conductivity signal and attempt a Zero calibration. For
example…
0*01uS 25.0oc
Cond. ZERO Calibration,Press Enter
6. When the reading has stabilised at or near zero, press to calibrate or to quit. The “ ∗”
will not be removed after a zero calibration.
Standard Calibration
7. Place the Conductivity sensor into a sample of Conductivity standard. Ensure that it is
immersed correctly, as per the diagram below.
DO NOT place the sensor directly into the bottle of standard. Discard the used sample of
standard after use.
8. Select Conductivity Calibration ( →→ F1:Calibrate →→ F2:Conductivity). The
calibration screen will be displayed with the Conductivity standard to be used. For example…
2*86mS 25.0oc
Cond. 2760uS Calibration,Press Enter
9. When the reading has stabilised, press to calibrate. The “ ∗” will now be replaced by a
decimal point if calibration was successful.
10. The 90-FL is now calibrated for Conductivity and is ready for use in this mode.
Ensure that the sensor is immersed at least as deeply as per the diagram in step 7 for all sample
measurements.

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4.5 Conductivity Calibration Notes
1. A Zero calibration should be performed at least monthly. In low conductivity applications
(where a zero error is particularly significant), a zero calibration may have to be done weekly.
2. A Standard calibration should be performed at least weekly. Of course, more frequent
calibration will result in greater confidence in results.
3. Conductivity and TDS calibration data is stored separately in memory. Ensure that the
90-FL has been correctly calibrated for the mode in which it will be used. The 90-FL does not
require re-calibration when alternating between Conductivity and TDS modes, providing the
instrument has been correctly calibrated for each mode on the k factor sensor to be used.
4. All calibration information is retained in memory when the 90-FL is switched off. This
information can be recalled or printed later using the GLP function (see section 8).
5. The 90-FL 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 4.2).
6. Calibration settings for k=0.1, k=1 and k=10 sensors are NOT stored separately.
The 90-FL requires re-calibration when a new k factor sensor is connected.
4.6 Conductivity Calibration Messages
1. If a Zero Calibration has been successfully performed, the 90-FL will display the following
message…
0.00uS 25.0oc
Calibration OK, Zero=0.01uS
2. If a Standard Calibration has been successfully performed, the 90-FL will display the following
message and the calculated k factor of the sensor. For example…
2.76mS 25.0oc
Calibration OK, k=0.99
3. If a Standard Calibration has failed, the 90-FL will display the following message and the
calculated k factor of the sensor. For example…
Calibration Failure. Check STD=2760uS/cm
k=3.64, Exceeds Limit
Notes
1. The allowable k factor range is +/-25% of nominal. This range is ample to allow for correctly
functioning Conductivity sensors. If calibration fails due to the k factor being outside these
limits, then please consult the Troubleshooting guide (section 16.3) for possible remedies.

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5. TDS Mode
5.1 Selecting TDS Mode
1. Select TDS Mode ( →→ F2:Mode →→ F4:TDS).
2. The 90-FL now proceeds to TDS measurement mode. Note that a “ ∗∗ ” is shown in place of the
decimal point until a successful calibration has been performed (see section 5.4).
5.2 Setting the TDS calibration standard
The factory default for this item is 36.00 ppK. If this is satisfactory, go directly to section 5.3.
1. Select the TDS Standard entry
(→→ F4:Setup →→ F1:Standards →→ F2:TDS).
The following screen is now displayed…
TDS Standard:36.00ppK
Range 20 ppM to 500 ppK
2. Type in the value of the TDS standard that is to be used for calibration, including the decimal
point. Use the key to make any corrections.
3. Press to save the value of the standard solution.
Alternatively, press to quit without changing the current setting.
4. The 90-FL will now ask you to enter the units for the TDS standard…
TDS Standard:36.00
Select Units F1:ppM F2:ppK
Press to set the TDS Standard as ppM (parts per Million).
Press to set the TDS Standard as ppK (parts per Thousand).
5. The TDS standard is now programmed for use at calibration.