Correcting For Positional Error - Siemens SITRANS P DS III Operating Instructions Manual

Operator control functions via PROFIBUS

7.12 Correcting for positional error

Calibrating the lower point
To calibrate the lower point, proceed as follows:
1. Call up the dialog "Sensor Trim".
2. Apply the reference pressure for the lower sensor trim point.
3. Enter the value of the reference pressure in the field "Lower Sensor Trim Point".
4. Click on "Transfer".
In the field "Pressure cleaned raw value", observe the effect of the calibration. In the "Lower
Sensor Trim Point" box, you can see whether the new trim point was applied.
Calibrating the upper point
To calibrate the upper point, proceed as follows:
1. Call up the dialog "Sensor Trim".
2. Switch to the "Upper Sensor Trim" tab.
3. Apply the reference pressure for the upper sensor trim point.
4. Enter the value of the reference pressure in the field "upper sensor trim point".
5. Click on "Transfer".
In the field "Pressure cleaned raw value", observe the effect of the calibration. In the "Upper
Sensor Trim Point" box, you can see whether the new calibration point was applied.
After both points have been calibrated, the status of the measured value must be "Good". If
the status "Bad, configuration error" is displayed, the calibration was smaller than the
smallest calibration span. You must move the trim points away from one another by moving
one of the two trim points.
See also
LO calibration (Page 91)
HI calibration (Page 92)
7.12 Correcting for positional error
External influences can affect the original zero point. External influences include:
● Mounting position
● Ambient temperature
● Installation-caused preset pressures, for instance fluid columns in the pressure line to the
pressure transmitter
● The screw-mounting on the process plant, e.g. measuring ranges from 1 to 20 mbar
(differential pressure), can respond more sensitively to the screw-mounting.
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SITRANS P DS III/P410 with PROFIBUS PA
Operating Instructions, 02/2016, A5E00053276-08