ProMinent DULCOMETER diaLog DACb Assembly And Operating Instruction page 105

Measuring and control behaviour
of the controller during calibration
During calibration the actuating outputs
are deactivated. Exception: a basic
load or a manual control variable has
been set. This remains active. The
measured value output
[standard signal output mA] is frozen,
corresponding to its settings in the mA
output menu.
When calibration/testing has been com‐
pleted successfully, all of the error
checks relating to the measured value
are restarted. The controller saves all
the determined data for zero point and
slope upon a successful calibration.
The measured value frozen at the start of cali‐
bration is suggested as a reference value. The
reference value can be set using the arrow
keys. Calibration is only possible if the refer‐
ence value is ≥ 2 % of the measuring range of
the sensor.
NOTICE!
Prerequisites for correct calibration of
the sensor slope
– The reference method needed is
used, depending on the feed
chemical used (e.g. DPD 1 for free
chlorine).
– The run-in period for the sensor
has been complied with; refer to
the operating instructions for the
sensor.
– There is permitted and constant
flow at the in-line probe housing
– There is temperature balance
between the sensor and the
sample water
– There is a constant pH value in the
permitted range
Material required for calibration of ampero‐
metric sensors:
A reference method suitable for the meas‐
n
ured variable in question
Calibration
105