- -
19
8.
Press the CAL key. The CAL symbol is turned on. The unit of measurement (
μ
S/cm or mS/cm)
appears on the comment line. If the calibration solution conductivity is sufficiently close (-30%
to +50%) to one of the standard solutions, the secondary line displays the value. Otherwise it
displays the calculated value according to current settings. In the central line the solution con-
ductivity value is indicated according to the cell constant current settings.
9.
Use the arrows to select the conductivity value
determined at point 4 and confirm using
ENTER. If the ERR indication appears, see the note below.
10.
The cell constant nominal value (KCELL) and the temperature coefficient
α
T
set to 0 are dis-
played. Pressed repeatedly the ENTER key allows the calibration on the point to be repeated,
for example, in order to obtain a more stable value.
11.
To end the probe calibration, press
χ
.
Ω
.TDS/ESC.
12.
Go back to the MENU and select ALPH: re-enter the temperature coefficient as it was before
the calibration.
13.
Rinse the probe with water. If you are then going to perform low conductivity measurements,
we recommend rinsing the probe using distilled or bidistilled water.
The instrument is now calibrated and ready for use.
NOTES:
•
Without having pressed ENTER at all, the calibration is interrupted by pressing
χ
.
Ω
.TDS/ESC;
the previous values will continue to be used.
•
Upon confirming the calibration by using ENTER, the instrument checks that the correction to
the conductivity does not exceed the 70% or 150% limits of the theoretical value. If the calibra-
tion is rejected because it is considered to be excessively corrupted, the
CAL ERR
message will
appear, followed by a long beep. The instrument remains in calibration mode and maintains the
previous calibration values.
•
The most frequent causes of error are due to the probe malfunctioning (deposits, dirt,…) or to the
standard solutions deterioration (bad preservation conditions, alteration due to pollution with dif-
ferent conductivity solutions,…).
•
If the measurement is in TDS, resistivity or salinity, on the pressing of CAL, the instrument goes
automatically in conductivity calibration.