CHAPTER 2: INSTALLATION
PQMII POWER QUALITY METER – INSTRUCTION MANUAL 2–19
2.2.12 RS232 Front Panel Port
A 9-pin RS232C serial port provided on the front panel allows the user to program the
PQMII with a personal computer. This port uses the same communication protocol as the
rear terminal RS485 ports. To use this interface, the personal computer must be running
the EnerVista PQMII Setup Software provided with the relay. Cabling to the RS232 port of
the computer is shown below for both 9-pin and 25-pin connectors.
FIGURE 2–14: RS232 Connection
2.2.13 Dielectric Strength Testing
It may be required to test the complete switchgear for dielectric strength with the PQMII
installed. This is also known as “flash” or “hipot” testing. The PQMII is rated for 1500 V AC
isolation between relay contacts, CT inputs, VT inputs, control power inputs and Safety
Ground Terminal 6. Some precautions are necessary to prevent damage to the PQMII
during these tests.
Filter networks and transient protection clamps are used between the control power, serial
port, switch inputs, analog outputs, analog input, and the filter ground terminal 5 to filter
out high voltage transients, radio frequency interference (RFI) and electromagnetic
interference (EMI). The filter capacitors and transient absorbers could be damaged by the
continuous high voltages relative to ground that are applied during dielectric strength
testing. Disconnect the Filter Ground (Terminal 5) during testing of the control power
inputs. Relay contact and CT terminals do not require any special precautions. Do not
perform dielectric strength testing on the serial ports, switch inputs, analog input or analog
output terminals or the PQMII internal circuitry will be damaged.
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