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5. TDS Calibration
5.1 Calibration Procedure
1.
Plug the Conductivity sensor into the
Conductivity/Salinity
socket.
If a k=0.1 or k=10 sensor is being used, ensure that the
WP-81T
is set to the
correct k factor before using the instrument (see section 14).
2.
Switch the meter on.
3.
Select TDS Mode.
→
F3:Mode
→
F3:TDS
4.
Rinse the Conductivity electrode in distilled water. Shake off as much water as
possible. Blot the outside of the electrode dry. DO NOT BLOT THE
ELECTRODE WIRES.
5.
Zero Calibration
Let the electrode dry in air.
Select TDS Calibration.
→
F1:Cal.
→
F1:TDS
6.
When the reading has stabilised at or near zero, press the
key to calibrate.
The
∗
will not be removed after a zero calibration.
7.
Standard Calibration
Allowable TDS standards are 69.5ppM, 2.00ppK, 8.00ppK, and 36.0ppK, and
should be selected according to your range of interest.
If the
WP-81T
does not recognise the standard, it will display the message,
“
NOT STD
” during calibration. Calibration will fail if this message is
displayed.
Place the electrode into a sample of TDS standard, so that it is immersed at
least to the vent hole in the white plastic cover. The white plastic cover
MUST be in place for correct readings.
DO NOT
place the electrode directly into the bottle of standard. Discard the
used sample of standard after use. It is advisable to use a narrow sample vessel
to minimise the use of standard solution.
8.
Select TDS Calibration.
→
F1:Cal.
→
F1:TDS
9.
When the reading has stabilised, press the
key to calibrate.
The
∗
will now be replaced by a decimal point, if calibration was successful.
10.
The
WP-81T
is now calibrated for TDS and is ready for use in this mode.