Reliance Electric 57404C Network Communication Module

Reliance Electric AutoMax Network Communication Module (57404C/57C404C) provides the network interface that lets AutoMax PLC racks share control and status data over the AutoMax DCS-NET network, a distributed communications fabric for AutoMax controllers. The module connects to the network via a coaxial cable and offers an RS-232-compatible asynchronous link through a 25-pin D-shell connector; two thumbwheel switches configure the drop number, and a seven-segment LED displays error codes to guide troubleshooting. The device is designed for use within AutoMax rack networks, with every rack on the network typically containing a Network Communication Module to enable inter-rack communication, as described in AutoMax operation manuals (e.g., J2-3001). In operation, it transmits and receives data between racks, with status indicators and watchdog-related diagnostics (for example, if the OK indicator LED is off, a local watchdog failure is likely; an LED code “A” indicates an invalid drop number, and “C” signals a network fault).