The 57552-4 is a Distributed Power System Universal Drive Controller Module (UDC) that was originally produced as a part of the Reliance Electric AutoMax system. It may have also been sold under the ABB or Baldor Reliance product lines, but it has since been discontinued. AX Control still attempts to keep this module in stock though.
The 57552-4 is a user-programmable control system that uses microprocessors to control AC and DC drives in real-time. It has 256 Kbytes of non-volatile read/write flash memory, 512 Kbytes of volatile SRAM, and 4 Kbytes of dual-port SRAM. This module has the ability to connect to two different PMIs using a fiber-optic link. It can be plugged into an AutoMax card rack assembly, taking up only one of its slots. Up to 10 UDC modules can be plugged into a single rack, meaning that a single rack now has the ability to control up to 20 drives. It can communicate with the processor module on the rack using the Multibus.
The 57552-4 has many features on its faceplate. It has a series of six LED indicators. These are labeled Card OK, OS OK, COMM A OK, DRV A FLT, COM B OK, and DRV B FLT. There are test switches that are numerically labeled 1-3 and N.O. There are meter ports that are numerically labeled 1-4 and COM. There are two sets of com ports. COMM A ports are labeled XMT and RCV. COMM B ports are also labeled XMT and RCV.