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WIKA operating instructions pressure transmitter, model IS-3
EN
14243628.02 10/2018 EN/DE
6. Commissioning, operation / 7. Adjusting the zero point and span
6.4 Function of the test circuit for 2-wire
This function is only possible for instrument designs with a field case.
Using the test circuit, it is possible to carry out a current measurement during normal operation without disconnecting
the pressure transmitter. For this purpose, connect an ammeter suitable for your Ex applications (internal resistance < 15
Ω) to the t
est
+
and test- terminals.
Functional check
The output signal must be proportional to the prevailing pressure. If this is not the case, this may indicate a damaged
diaphragm of the process connection. In this case, see chapter 9 “Faults”.
7. Adjusting the zero point and span
The span-setting potentiometer is used for factory adjustment and should only be readjusted if calib-
ration equipment is available which has at least three times the accuracy of the pressure transmitter.
7.1 Access to potentiometer
To gain access to the potentiometers, open the instrument as follows:
Clamping nut (figure A)
1. Disconnect the electrical connection (1) from the instrument.
2. Remove the clamping nut (2).
3. Carefully pull the instrument connector (3) from the instrument.