The PCM500 is Unipower's basic-level DC power plant control and monitoring unit, compact enough for 1RU rack mounting in 19- or 23-inch racks. It centralizes float voltage adjustment for the entire DC bus while independently monitoring battery sense, current, temperature, and fuse status across the plant.

What does the PCM500 control and monitor?

The controller manages up to 16 rectifiers distributed across a maximum of 4 shelves. Current share and remote adjust signals keep all rectifiers balanced. On the monitoring side, it accepts two low-voltage disconnect inputs, five fuse alarm inputs, battery voltage and current (via external 50mV shunt), and an optional temperature compensation probe with 20 ft cable.

How do the alarm outputs work?

Eight front-panel LEDs indicate system status, each backed by an isolated Form C relay contact. The alarms cover equalize mode (EQA), rectifier failure minor (1 unit) and major (2+ units), AC failure, fuse/breaker failure, low-voltage disconnect, and battery overvoltage/undervoltage thresholds — giving the NOC or site technician a complete fault picture without additional hardware.

Which options are available?

The model code PCM500 – [Voltage] – [Option] – [Option] – [Option] lets the user specify plant voltage (1 = −48V Pos. Gnd., 2 = +48V Neg. Gnd., 3 = −24V Pos. Gnd., 4 = +24V Neg. Gnd.) and add up to three option modules: EV (equalize voltage mode), MP (digital voltmeter/ammeter panel — requires specifying a 50mV shunt rating from 25A to 2000A), and TC (battery temperature compensation). All options are field-orderable at time of purchase.

Frequently Asked Questions

Can the PCM500 be used with non-Unipower rectifiers?

The controller is designed for Unipower Mercury and Vanguard rectifier shelves. Its current-share and remote-adjust interfaces are proprietary to those shelves and have not been validated with third-party rectifier systems.

What is the difference between the PCM500 and a more advanced controller?

The PCM500 provides essential DC plant supervision — centralized float voltage, eight alarm relays, and basic battery monitoring. It does not include a network interface, SNMP, or web-based management. Sites needing remote monitoring should consider a gateway-equipped system upstream of the PCM500.