5.3
Calibration Messages
1. If a temperature calibration has been successfully performed, the
WP-
84
will display the following message and the offset value of the
sensor.
Calibrate OK
Offset=
1.0
o
c
2. If a temperature calibration has failed, the
WP-84
will display the
following message and the failed offset value of the sensor.
Calibrate Failed
Offset= 10.5
o
c
6.
ATC Coefficient
The Automatic Temperature Compensation (ATC) Coefficient is the rate at
which the WP84 compensates for temperature effects on the Conductivity
of the solution. The following all affect the ATC Coefficient of a solution…
�
The type of salts dissolved in the solution.
�
The concentration of the salts dissolved in the solution.
�
The temperature of the solution.
It is therefore impossible to set a single ATC Coefficient in the factor
which will be correct for all solutions which the
WP-84
will be used to test.
The ATC Coefficient is set to 2.0 %/
O
C in the factory. This figure is suitable
for environmental waters whose predominant dissolved salt is Sodium
Chloride
at
moderate
concentrations,
being
measured
between
approximately 15 and 30
O
C.
The calculation of Salinity from the Conductivity reading incorporates the
ATC Coefficient as defined for sea water. The user set ATC Coefficient is
not used.
6.1
Setting the ATC Coefficient
1. Select the ATC entry screen (
�
F1:Cal.
�
F4:ATC %
).
2. The ATC entry setting screen is displayed…
Enter ATC
�
2.0
�
��
:Set
F1:Store
Use the
and
keys to scroll to the desired ATC Coefficient
setting. The available range is 0.0 to 4.0 %/
O
C.
3. Press
to store the new setting.
Press
to quit and retain the current setting.
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