Reliance Electric 57C442B Data Highway Plus Interface Module

Reliance Electric 57C442B Data Highway Plus Interface Module is the direct DH+ bridge that lets an AutoMax rack communicate on the Allen-Bradley Data Highway Plus network, making the AutoMax chassis appear as a single DH+ station to other network devices. Designed for installation in any slot of an AutoMax rack that contains at least one AutoMax Processor, it can communicate with up to four AutoMax Processors within the same rack. The module uses an 8 MHz microprocessor and shares 32K of dual-port memory with the AutoMax backplane, enabling data transfers between PLC-5–lookalike registers and remote Allen-Bradley equipment using commands such as Word Range Read, Word Range Write, and Read-Modify-Write. Station addressing is configured with two thumbwheel dials (0–77), and the faceplate provides status indicators, including a green OK LED and a seven-segment fault-code display.