Siemens MS Series, Instruction Manual, Page: 98 / 130

SITRANS P, MS series
98
C79000-B5674-C40-04
Functions/Operation via HART®
4.15.1 Trimming the Lower Sensor Correction Point
The pressure at which the lower sensor correction is to be made is applied to the
transmitter. The transmitter is instructed by the SIMATIC PDM or the HART® hand-
held to accept this pressure. This represents an offset shift of the characteristic (1.,
Figure 18, p. 98).
4.15.2 Trimming the Upper Sensor Correction Point
The pressure at which the upper sensor correction is to be made is applied to the
transmitter. The transmitter is instructed to accept this pressure by SIMATIC PDM or
the HART® communicator. This corrects the slope of the characteristic (2., Figure
18, p. 98). The lower sensor correction point is not affected by this. The upper cor-
rection point must be greater than the lower correction point.
4.16 Current Transmitter Correction
The current output by the transmitter can be corrected independently of the pressure
measuring circuit. The correction can only be made at 4 mA and 20 mA. This function
is suitable for compensating inaccuracies in the processing chain following the
transmitter.
A: output characteristic
B: characteristic after lower sensor correction
C: characteristic after upper sensor correctio
Figure 18 Sensor correction
A
1.
2.
B
C
measured
pressure
B: Parallel shift
C: Slope change
1.: A
2.: B
lower
correction point
upper
correction point
default pressure