Precision Control Systems 930 User Manual

Page 22

Model 930 ControlIR

Instruction Manual

Maintenance and Trouble Shooting

Research, Inc.

Page 18 of 25

Panel Voltmeter
Calibration

Temperature Controller
Option

2. Voltmeter Option or No Options: When REMOTE setpoint mode is selected, use

a 0-5 VDC source for an input. Adjust the zero and span potentiometers on the
power controller. The SPAN potentiometer is adjusted for 90 percent of rated line
voltage for 4.5 VDC input. The ZERO potentiometer is adjusted for 0 Volts
output when the local setpoint is set to 000 dial divisions.

3. Temperature Controller option only: When AUTO setpoint mode is selected, the

temperature controller is used as the source for the input. Adjust the zero and span
potentiometers on the power controller. The SPAN potentiometer is adjusted for
90 percent of rated line voltage for 90 percent output of the temperature controller.
The ZERO potentiometer is adjusted for 0 volts output when the temperature
controller is set to 0 percent.

The front panel load voltmeter is calibrated to match as closely as possible the true
RMS voltage measured at the load terminals.

1. Connect a true RMS DVM to load 1 and load 2.

2. Connect another DVM across pins 1(+) and 2(-) of the EXT 200 RMS voltage

transmitter.

3. Turn the HEATER switch to OFF. Measure the voltage of EXT 200 pins 1(+) and

2(-) to be 0.0 VDC +/- 10 millivolts. Adjust the EXT 200 zero potentiometer if
necessary.

4. Verify the panel voltmeter reads 0 volts. If necessary, carefully remove the front

cover of the meter and adjust the zero potentiometer for 000 +/- 1 reading.

5. Turn the Heater switch to ON. Adjust the LOCAL SETPOINT potentiometer for

the following load voltage based on the voltage your system is configured for:

480 VAC units: 450 VAC
240 VAC units: 225 VAC

6. Measure the voltage of EXT 200 pins 1(+) and 2(-) to be the following voltage +/-

10 millivolts:

480 VAC units: 3.750 VDC
240 VAC units: 1.875 VDC

7. Verify that the panel voltmeter reads the voltage as set in Step 5 above. If

necessary, carefully remove the front cover of the meter and adjust the span
potentiometer for a +/- 1 reading.

Refer to the temperature controller manual for calibration instructions.