As a data gathering device for plant automation systems that integrate process,

instrument, and electrical requirements, all monitored values are available via one of two

RS485 communication ports running the Modbus protocol. If analog values are required

for direct interface to a PLC, any of the monitored values can output as a 4 to 20 mA (or 0

to 1 mA) signal to replace up to four (4) separate transducers. A third RS232

communication port connects to a PC from the front panel for simultaneous access of

information by other plant personnel.

With increasing use of electronic loads such as computers, ballasts, and variable

frequency drives, the quality of the power system is important. With the harmonic analysis

option, any phase current or voltage can be displayed and the harmonic content

calculated. Knowledge of the harmonic distribution allows action to be taken to prevent

overheated transformers, motors, capacitors, neutral wires, and nuisance breaker trips.

Redistribution of system loading can also be determined. The PQMII can also provide

waveform and data printouts to assist in problem diagnosis.

Applications of the PQMII

• Metering of distribution feeders, transformers, generators, capacitor banks, and

motors

• Medium and low voltage three-phase systems

• Commercial, industrial, utility

• Flexible control for demand load shedding, power factor, etc.

• Power quality analysis

• System debugging