Pulsafeeder ELMA NEMA 4X, Installation, Operation & Maintenance Manual

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c. With the voltmeter in the DC mode, measure and record the voltage across
TB-1 and TB-3 at 0% and 100% process signal
d. Remove the process signal from the board
e. Manually adjust the micrometer hand knob to 0% stroke setting
f. Locate the positive lead of the voltmeter to the wiper terminal (black lead) of
the feedback potentiometer while the negative lead is on TB1-1. Adjust the
“Low Cal” potentiometer so that the wiper voltage equals that read in Step C
at 0% process signal.
g. Manually turn the hand knob to the 100% setting and adjust the “High Cal”
trim potentiometer so that the wiper voltage now equals that read in Step C at
100% process signal.
h. Repeat Steps f and g until the voltage from the feedback wiper and stabilized
to match the respective voltages read from Step C.
i. Reconnect the process signal and place the override toggle switch to Auto
position. Verify proper operation. If the actuator fails to fully adjust to either
endpoint or does not switch off, then readjust the “Low” or “High Cal” trim
potentiometer depending on which endpoint is off, until proper adjustment is
achieved.
Remote Auto/Manual Calibration
2. Comparator calibration procedure to be used with units supplied for MANUAL
control from a remote manual potentiometer or units supplied for AUTO/MANUAL
control from a remote process signal and remote manual potentiometer.
a. With the override toggle switch in the "man" position wire the actuator and
remote enclosure per the supplied wiring diagram.
b. For AUTO/MANUAL units turn the remote control switch to the "auto"
position.
c. Perform steps b-i as outlined in Procedure 1). For MANUAL units substitute a
signal generator in place of the process signal.
d. Place both the override toggle i switch and remote control switch in the' "man"
position.
e. With the manual stroke adjustment potentiometer at 0% measure the voltage
across TB1-1 and TB1-3. Adjust the "Low" trim potentiometer on the back of
the remote potentiometer assembly until the measured voltage equals that
measured in Step 1-c at 0% process signal.
f. Turn the manual stroke adjustment potentiometer to 100%. Now adjust the
"High" trim potentiometer on the back of the potentiometer assembly until the
voltage across the TB1-1 and TB1-3 equals that measured in step 1-c at
100% process signal.
g. Repeat steps e and f until the measured voltages are stabilized to match the
respective voltages read from step 1-c.
h. Place the override toggle switch in the “auto” position. Verify proper operation
of the controller through the stroke adjustment potentiometer. If the actuator
fails to fully adjust to either endpoint or reaches one endpoint and does not
switch off, then readjust the “Low” or “High” trim potentiometer on the back of
the potentiometer assembly depending on which endpoint is off, until proper
adjustment is achieved.