16
4.4 Conductivity Calibration
To achieve accurate Conductivity/TDS/Salinity results, the
90-FLMV
requires calibration to a
known Conductivity standard. The TDS and Salinity values are derived from the Conductivity
reading and do not require a separate calibration. The conductivity of a solution varies with
temperature. The
90-FLMV
uses Automatic Temperature Compensation (ATC) referenced to the
fixed temperature of 25
o
C.
Before attempting a Conductivity calibration, ensure that the
90-FLMV
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 SENSOR WIRES.
Zero Calibration
3.
Let the sensor dry in air.
4.
Select Conductivity Calibration (
→
→
→
→
F1:Calibrate
→
→
→
→
F2:Conductivity
).
5.
The
90-FLMV
will recognise the low conductivity signal and attempt a Zero calibration. For
example…
0*01uS 25.0
o
c
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 25.0
o
c
Cond. 2760uS Calibration,Press Enter
