Specifications

The Drive Multimeter positions are defined and detailed in the
Sections where the meter resistors are located.
4.7.4
Multimeter Probe
The multimeter uses a flexible coiled patch cord with a clip-on
probe for convenient measurement of voltages in the non-
interlocked compartment. Measurement ranges available are 0
to 30 VAC Peak, 0 to +3 VDC, 0 to +30 VDC, and 0 to -30 VDC.
Resistor R5, 29.4K 1%, is the multiplier resistor for the 0-3 Volt
range. The total 30K resistance required for this range includes
the meter resistance.
Resistor R3, a 301K 1% resistor, is the multiplier resistor for the
0-30 Volt range. Positive and negative voltage ranges are ob-
tained by grounding either the negative or positive meter termi-
nal through S1.
For AC Voltage measurements, CR1, R4, C1 and R1 make up a
peak detector. Resistor R2 is the multiplier resistor for the ac
voltage range.
4.7.5
Maintenance
There are no maintenance adjustments on the Drive Multimeter
board.
4.7.6
Troubleshooting
The followinginformation contains general troubleshooting tips
and any precautions if applicable.
Check connectors to be certain they are properly and firmly
inserted. Check ribbon cables for possible damage, such as
crimping.
Visually check S1. Liquid or spray contact cleaners should be
used with caution; don’t use any cleaner that could leave a
residue that might collect dirt and dust.
Use an accurate digital multimeter to measure resistances. It
may be necessary to remove plug-in modules or other connec-
tors to eliminate parallel resistance paths that could affect the
measurement.
CAUTION
When measuring resistances in any metering circuit, change the mul-
timeter position to some OTHER range. Ohmmeters could provide
enough current to damage the sensitive meter movement.
When checking the meter, remove all power from the transmitter
and disconnect P4 and P5 from the multimeter board to elimi-
nate any possible parallel current paths. Use a battery or low-
voltageDC power supply and current limiting resistor to provide
a low current (50 to 100 microamperes) through the meter
movement,with a low-current meter of knownaccuracy in series
with M1.
12/16/03 888-2339-002 4-17
WARNING: Disconnect primary power prior to servicing.