Reliance Electric 57C413B Common Memory Module

Technical Dossier

Product Details And Specifications

Reliance Electric 57C Series: Comprehensive Module Range and Technical Overview

The Reliance Electric 57C series represents a foundational control platform deployed across global heavy industry, including petrochemical refineries, nuclear power generation facilities, pulp and paper mills, and continuous-process chemical plants. Engineered under Reliance Electric's AutoMax distributed control architecture, the 57C series provided deterministic scan-cycle control, high-density I/O integration, and multi-rack backplane communication in environments where mean-time-between-failure (MTBF) requirements exceed 100,000 hours. Installed base estimates place the 57C platform in thousands of production-critical applications across North America, Europe, and Asia-Pacific, many of which remain in active service under long-term maintenance contracts. The 57C413B Common Memory Module is a shared-memory arbitration card that enables deterministic data exchange between multiple CPU racks within a single AutoMax control node, making it a single point of continuity for multi-processor configurations.

The Evolution of 57C Series Architecture

The 57C platform was introduced by Reliance Electric in the mid-1980s as part of the AutoMax Programmable Controller system, designed to bridge the gap between relay-logic replacements and full distributed control systems (DCS). Early revisions used parallel backplane buses operating at TTL logic levels, with memory modules providing static RAM (SRAM) arbitration between co-resident processors. The architecture evolved through several hardware revisions to address bus contention latency, expanding addressable memory from 16KB in early variants to 256KB+ in later production runs.

Following Rockwell Automation's acquisition of Reliance Electric in 1995, the 57C series was maintained under the Rockwell/Allen-Bradley support umbrella but received no new hardware development. By the early 2000s, the platform entered a formal end-of-life (EOL) phase, with Rockwell discontinuing factory repair services for most 57C modules by 2010. The recommended migration path is to Allen-Bradley ControlLogix (1756 series) or PlantPAx DCS, though the capital cost and process downtime associated with full migration has led the majority of installed-base operators to pursue third-party lifecycle extension strategies instead.

Compatibility note: 57C modules are backplane-specific and are not interchangeable with the earlier 57C300 or 57C400 sub-families without verifying firmware revision and backplane slot addressing. Mixed-revision installations require careful revision-level matching to avoid bus arbitration faults.

57C Series Full Catalog & Functionalities (SKU List)

CPU & Controller Modules

• 57C401: AutoMax CPU module, single-processor, 16KB user memory, base controller card
• 57C402: AutoMax CPU module, enhanced scan rate, 32KB user memory, relay ladder support
• 57C404: AutoMax CPU module, high-speed version, extended instruction set for math-intensive loops
• 57C405: AutoMax CPU module, dual-port RAM interface, supports peer-to-peer data sharing
• 57C406: AutoMax CPU module, 64KB user memory, supports structured text and function block programming

Memory Modules

• 57C413B: Common Memory Module, shared SRAM arbitration, multi-CPU rack data exchange, 128KB capacity
• 57C413A: Common Memory Module, earlier revision, 64KB capacity, single-arbitration bus
• 57C414: Extended Memory Module, battery-backed SRAM, retains program on power loss, 256KB
• 57C415: Flash Memory Module, non-volatile program storage, field-programmable, 512KB

Digital I/O Modules

• 57C420: 16-point 24VDC digital input module, sink/source configurable, LED status per channel
• 57C421: 32-point 24VDC digital input module, high-density, common return bus
• 57C430: 16-point 24VDC digital output module, 0.5A per channel, short-circuit protected
• 57C431: 32-point 24VDC digital output module, transistor output, group isolation
• 57C435: 16-point relay output module, Form C contacts, 2A per channel, 120/240VAC rated

Analog I/O Modules

• 57C450: 8-channel analog input module, 4–20mA / 0–10V selectable, 12-bit resolution
• 57C451: 16-channel analog input module, differential input, 13-bit resolution with sign
• 57C460: 4-channel analog output module, 4–20mA, 12-bit DAC, loop-powered

Communication & Adapter Modules

• 57C480: AutoMax Network Adapter, coaxial token-ring network interface, 5Mbps
• 57C481: AutoMax Network Adapter, fiber-optic version, noise-immune for high-EMI environments
• 57C490: Remote I/O Adapter, interfaces 57C backplane to Allen-Bradley 1771 remote I/O network

Power Supply Modules

• 57C500: AutoMax Power Supply, 5VDC/3A backplane power, 120/240VAC input, single-slot
• 57C501: AutoMax Power Supply, redundant configuration support, hot-swap capable with 57C502

Sourcing Hard-to-Find & Obsolete 57C Series Parts

The 57C series has been formally discontinued by Rockwell Automation. OEM factory repair and new-manufacture availability ceased for the majority of modules between 2008 and 2015. DriveKNMS maintains a dedicated inventory of tested surplus and refurbished 57C modules sourced from decommissioned plant equipment, controlled-environment warehouses, and verified industrial surplus channels.

For the 57C413B specifically, DriveKNMS stocks units that have passed full functional verification including shared-memory arbitration cycle testing, bus termination resistance measurement, and SRAM data retention validation. All units are shipped with a documented test report. Exchange programs are available for core-return credit. Lead times for in-stock units are typically 1–3 business days for international shipment.

For operators running multi-CPU AutoMax nodes where the 57C413B is the sole arbitration point, DriveKNMS recommends maintaining a minimum of one cold-spare unit on-site. Failure of the common memory module in a multi-processor configuration results in a full node fault with no graceful degradation path.

Quality Control for the 57C Series Range

All 57C series modules received by DriveKNMS undergo a structured incoming inspection and functional test protocol before being listed as available inventory. The process for memory and CPU modules includes: visual inspection for PCB damage, corrosion, and component substitution; SRAM cell integrity test using a walking-ones/walking-zeros pattern across the full address space; backplane edge connector resistance measurement (target: <0.1Ω per pin); bus arbitration timing verification using a dedicated AutoMax backplane test fixture; and 48-hour burn-in at 45°C ambient to screen for early-life failures.

For I/O modules, each channel is individually stimulated and measured against the published accuracy specification. Analog modules are calibrated using NIST-traceable reference standards. Digital output modules are load-tested at 100% rated current per channel. All test data is retained for a minimum of 5 years and is available to customers on request.

Modules that fail any test parameter are either repaired to specification by component-level technicians or quarantined and scrapped. No module is listed as available inventory without a passing test record.