Reliance Electric 57C413B Common Memory Module

Technical Dossier

Product Details And Specifications

Reliance Electric 57C Series Technical Notes

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.

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 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.