20 OI/ATS430–EN Rev. H
| Aztec ATS430 | Turbidity sensor
6.4.4 In process calibration
In process calibration is used when it is not possible to remove
the sensor from the process to perform the calibration. In this
calibration mode the actual sample is used to calibrate the
sensor.
The in process calibration takes place in two steps. During the
first step a grab sample is taken from the process, and the
sensor records the turbidity of the sample at that time. The
suspended solids content of the grab sample is then measured
in the laboratory and entered into the transmitter during the
second step.
Due to the inherent variability of both the turbidity and
suspended solids measurements, using a single point to
calibrate the suspended solids measurement can lead to sudden
jumps in the suspended solids value reported by the sensor.
(The ATS430 sensor supports an adaptive calibration mode,
which mitigates the occurrence of such jumps.) – refer to
AN/ANAINST/021-EN for details of adaptive calibration.
1.
At the Calibration Type screen, use the
/
keys to
select
Sample Collection
and press the
key (below the
OK
prompt):
2. Proceed to Section 6.4.5 (Sample collection) to start the
first part of the calibration.
6.4.5 Sample collection
1.
This is the first step of the calibration. On the next screen,
press the
key (below the
Next
prompt).
Performing this step erases any sample collection
performed previously. Only the last sample collection
performed is stored in the sensor.
2. On the following screen press the
key (below the
Continue
prompt) to start the data collection. The grab
sample should be taken as close to the sensor as possible
during this period.
The calibration process screen is displayed – the acquisition
can be cancelled at any time during the process by pressing
the
key (below the
Abort
prompt):
3. Once the acquisition is complete, Press the
key (below
the
Exit
prompt) to return to the main menu.
The value of the sample turbidity is now stored.
4. Proceed to Section 6.4.6 (Sample collection) to start the
second part of the calibration once the suspended solids
value has been determined.
Calibration Type
Sample Collection
Cancel
OK
1-Point Cal
2-Point Cal
Collection Complete
Manual Coefficient
Collect Sample
Abort
Continue
Start Collection?
Collect Sample
Abort
PV
0.000 mg/l
NTU
2000 NTU
Settling-Please Wait
Collect Sample
Exit
Procedure Complete
PV
0.000 mg/l
NTU
2000 NTU
