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7. Temperature Mode
The temperature readout must be calibrated before attempting pH or ppM Dissolved Oxygen
calibration and measurements.
The decimal point is replaced by a “
∗∗
” if the reading is not calibrated.
The
90-FL
is able to take Temperature readings from the Conductivity/TDS sensor or a separate
Temperature probe. Only one or the other can be connected at any one time. Ensure that the
90-FL
has been calibrated on the correct sensor.
7.1 Temperature Calibration
1.
Plug Conductivity/TDS or separate Temperature sensor into the
Cond/Sal
socket.
2.
Switch the meter on.
3.
Place the sensor into a beaker of room temperature water, alongside a good quality mercury
thermometer. Stir the sensor and the thermometer gently to ensure an even temperature
throughout the beaker.
4.
Select Temperature Calibration (
→
→
F1:Calibrate
→
→
F4:Temperature
).
The Temperature Calibration screen is now displayed…
Enter Actual Temperature : _ 24.0
O
c
Temperature Calibration Menu Quits
5.
The current reading from the sensor is displayed on the far right of the top line.
When this reading has stabilised, use the Numeric Keypad to enter the same temperature as
measured by the mercury thermometer.
6.
Press the
key to calibrate the temperature readout.
Alternatively, press the
key to abort temperature calibration.
The
90-FL
is now 1 point temperature calibrated. This will provide precision to approximately
±0.5
O
C. The following screen is displayed…
1 Point Calibration OK, Offset=0.1
o
c
Press Enter for Span Cal. or Menu Quits
Press
if ±0.5
O
C is adequate for your application. The
90-FL
will now return to normal
measurement mode and the “
∗∗
” in the Temperature readout will have been replaced by a
decimal point.
Press
to go on to a second point calibration if a higher degree of precision is required.
7.
When a second point calibration is being performed, the
90-FL
will now display the second
calibration screen..
Enter Actual Temperature : _ 36.0
o
c
15.0 > Temp > 35.0 Menu Quits
Please note that the sensor must now be placed into a container of water that is at least 10
O
C
higher or lower than the first calibration point.
An insulated container with around 1 Litre or more of water will provide a stable environment
to do the second point Temperature calibration. The Temperature of the water in a small,
uninsulated container will change too rapidly, making a successful second point calibration
virtually impossible.