Overview

The 57C423 is a Common Memory Module for the Reliance Electric AutoMax PLC and DCS 5000 systems. It stores configuration and shared data required by all processor modules in the rack, including I/O definitions, task scheduling parameters, and shared variables. Equipped with a lithium battery backup, the module ensures non-volatile memory retention during power outages. In multiprocessor AutoMax racks, the 57C423 must be installed in Slot 0 to enable full shared-memory functionality and coordinated control.

Technical Data

Typical Applications

The 57C423 enables high-performance distributed control in industrial systems by providing a shared memory space for multiple CPUs:

• Metal rolling mills – coordinating high-speed motor drive control with sequential I/O logic

• Large printing presses – synchronizing multiple processors managing motion control and peripheral devices

• Any multiprocessor AutoMax configuration – reducing inter-processor latency and ensuring tight synchronization across tasks

By centralizing shared configuration data, the module supports flexible and reliable multi-CPU architectures.

FAQ

Q1: Is the 57C423 mandatory in every AutoMax rack?
A: No, it is optional for single-CPU racks. However, in multiprocessor configurations, it is required to provide shared memory and bus arbitration.

Q2: How does the battery backup function?
A: The lithium battery powers the on-board CMOS RAM after the main rack power is removed, preserving critical configuration and shared data. The BAT OK LED confirms battery health.

Q3: What happens if the module is installed in a slot other than Slot 0?
A: In other even-numbered slots, the module can function as generic memory expansion, but it will not support common memory or multiprocessor coordination.

Q4: What software is required to configure the 57C423?
A: Configuration is handled via the ReSource AutoMax Programming Executive, typically versions 2.1E, 3.1C, or later, running on a host computer connected to the AutoMax system.