Remote Processing Units (RPUs) for refrigeration control are dedicated, self-contained controllers, with modular expansion capability.

Each RPU has 16 analog inputs, which may be configured for temperature, pressure, current, or versatile 4-20 mA signals. Each RPU has 8 digital outputs on board, and may be expanded up to 64 digital inputs and 64 digital outputs, using modular expanders. Up to 16 analog outputs with D/A expanders.

An RPU can support up to eight control 'devices'. Devices may be a chiller, compressor, pump controller, barrel room, etc. Each 'device' has a software module in the RPU, and a corresponding module in the PC software.

RPUs record data at ten minute and hourly intervals. The hourly data is kept for 72 hours on-board, in case the PC may be down. Eight channels of digital 'status' history is kept for each of the eight control channels. This data is also recorded at ten minute and hourly intervals.

The RPU programs are written in Forth and assembly code.