In Process Calibration; Sample Collection - ABB AWT420 Operating Instruction

AW T4 2 0 | U N I V E R S A L 4 - W I R E , D U A L- I N P U T T R A N S M I T T E R | O I/A W T4 2 0 - E N R E V. B

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:

• Sample collection

– A grab sample is taken from the process and the sensor
records the measured value of the sample at that time.
Note. The grab sample should be taken as close to the
sensor as possible during the data collection period.
• Collection complete
– The Total suspended solids of the sample is measured in the
laboratory and entered into the transmitter.
This sample must correspond to the last sample collection
step performed.
Sample collection
1 At the Calibrate level, press the
The Calibrate menu is displayed:
Calibrate
S1 : Turb TSS
S2 : Turb TSS
Hold Outputs
Back
2 Use the
/ keys to select the sensor to be calibrated,
and press the key to confirm selection.
The Sample Collection menu is displayed:
Calibrate
Sensor Cal
Temperature Cal
Edit Cal
Sample Collection
Collection Complete
Restore Cal Defaults
Back
key:
Select
Select
3 Use the keys to select Sample Collection and
/
press the key to proceed to the next step.
Collect Sample
Start Collection
Abort
4 Press the and key to proceed to the next step.
The collection process screen is displayed:
Calibrate
PV 3985 mg/l
NTU 4000 NTU
Settling - Please Wait
Abort
On completion the collection complete screen is displayed:
Calibrate
PV 3985 mg/l
NTU 4000 NTU
Procedure Complete
Abort
The value of the sample turbidity is now stored.
Note. The calibration can be canceled at any time during
the process by pressing the Abort key (
Continue
).
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