POSITION TRANSMITTERS
CALIBRATION
A - 6
3. Connect the field wiring to the terminal block. Connect a DC
voltmeter between TB1-1 (-) and TB1-2 (+).
4. Move the actuator to the 80% position. Adjust the resistor in
series with the 24-VDC supply until the voltmeter reads five VDC.
5. Move the actuator to the 0% position to verify that the voltme-
ter reads less than five VDC.
6. Move the actuator to the 100% position to verify that the volt-
meter reads greater than five VDC.
Calibrating the 4 to 20-mA Position Transmitter
Labels located inside the positioner cover show the location of
jumpers, test points, calibration potentiometers and field connec-
tion terminals for the position transmitter (Figs. A-1 and A-4).
1. Remove the FOR/REV jumpers, and place the CAL/OPER
jumpers in the calibrate (CAL) position (Fig. A-4).
2. Move the actuator to the 50% output position.
3. Insert ohmmeter leads into test jacks TP1 (-) and TP2 (+). If
the resistance value is between 940 and 1060 Ω, remove the ohm-
meter leads and proceed to Step 4. Otherwise continue with Step
3.
Figure A-4. Calibration Features for
4 to 20-mA Position Transmitter
FORWARD
C A LIB R AT E Z E RO SPA N
OPERATE
TP2(+) TP1(–)
REVERSE
T00789A
WARNING
The pneumatic supply pressure must be turned off before
removing the positioning cam. The final control element will
go to one end of the stroke and can cause a process upset.
Some process upsets may cause damage to equipment and
endanger personnel.
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