Reliance Electric 57409-G Analog Input Module

The Reliance Electric 57409-G (also cataloged as 57C409) is a two-channel isolated analog input module designed for Reliance AutoMax PLC racks. It provides galvanic isolation between the input signals and the controller backplane, helping protect the AutoMax system from noise and ground-loop issues in harsh industrial environments. Each channel accepts either a voltage input or a current loop signal, with voltage ranges selectable from +1 V, +5 V, +10 V, and +20 V, and a 4–20 mA current input range. The module performs a 12‑bit analog-to-digital conversion and delivers results to the AutoMax backplane, with documentation tied to instruction manual J-3637 (and related 57C409/J-3709 references). In practice, the 57409-G is used to read analog signals from sensors such as potentiometers and tachometers, as well as other drive-control and process-control instrumentation, feeding the local rack in an AutoMax or DCS 5000 system. The 57C409/57409 family variant is widely described in catalogs and surplus listings, reflecting its long-standing role as a compact, two-channel input option for legacy automation setups. When deployed in the appropriate AutoMax rack, this module enables reliable, isolated two-channel data acquisition for monitoring and control tasks across a range of industrial applications.