Siemens SITRANS P300 Operating Instructions Manual page 52

Operation
6.5 Local operation
The correlation between the measured pressure and the output current generated is linear.
The following formula can be used to calculate the output current.
Figure 6-6
I
p
MA
ME
Example of setting with reference pressure
A
B
C Setting limit point
Explanations for the example of setting with reference pressure
A
B
C 14 bar process pressure is created.
D The output current can be calculated for any input pressure using the "current calculation formula
6-14
Current calculation formula for setting
Output current
Pressure
Zero point
Limit point
Initial situation
Setting zero point
The measuring range is from 0 to 16 bar. You are changing the zero point from 0 to 2 bar and the
limit point from 16 to 14 bar. The span is then 12 bar.
2 bar process pressure is created.
Use the <MODE> key to switch the transmitter to mode 2. To set the zero point, press the keys
<UP> and <DOWN> simultaneously for 2 seconds.
If there is 2 bar input pressure, the transmitter produces an output current of 4 mA.
Use the <MODE> key to switch the transmitter to mode 3. To set the limit point, press the keys
<UP> and <DOWN> simultaneously for 2 seconds.
If there is 14 bar input pressure, the transmitter produces an output current of 20 mA.
for setting".
MA Old zero point
actual
ME Old limit point
actual
MA New zero point
target
ME New limit point
target
SITRANS P300 with HART communication
Operating Instructions, 06/2005, A5E00359579-02