GE PACSystems RX3i IC695CMM004LT: Serial Communications Module —

Technical Dossier

Product Details And Specifications

GE PACSystems RX3i Series: Comprehensive Module Range and Technical Overview

The GE PACSystems RX3i platform is one of the most widely deployed distributed control architectures in global heavy industry. Installed across petrochemical refineries, nuclear power generation facilities, offshore platforms, and continuous-process chemical plants, the RX3i backplane-based system provides deterministic scan-cycle control with high-availability redundancy options. The IC695CMM004LT is a 4-port serial communications module within this platform, providing RS-232/RS-485 multi-protocol serial connectivity for legacy field device integration — a critical function in brownfield installations where HART, Modbus RTU, and proprietary serial protocols remain the operational standard.

The Evolution of PACSystems RX3i Architecture

The PACSystems RX3i platform was introduced by GE Fanuc Automation (later GE Intelligent Platforms, now part of Emerson) as a successor to the Series 90-30 and Series 90-70 PLC families. The RX3i uses a universal backplane (IC695CHS007, IC695CHS012, IC695CHS016) that accepts both legacy 90-30 I/O modules and native RX3i modules, enabling phased migration without full system replacement.

Early RX3i CPUs (IC695CPU310, IC695CPU315) used a 300 MHz processor with 10 MB user memory. Subsequent generations introduced the IC695CPU320 (1 GHz, 64 MB), and the current IC695CPE330 and IC695CPE400 with multi-core architecture and embedded Ethernet. Communications architecture evolved in parallel: early serial-only connectivity (CMM002, CMM004) was supplemented by Ethernet NIU modules (ETM001, PNC001 PROFINET), and later by the IC695EIS001 EtherNet/IP Scanner. The IC695CMM004LT represents the mature serial communications tier — a stable, field-proven module that remains in active demand for legacy serial device integration in plants where full protocol migration is not economically viable.

PACSystems RX3i Full Catalog & Functionalities — IC695CMM004LT and Related SKUs

Communications Modules

• IC695CMM002: 2-port serial communications module, RS-232/RS-485, Modbus RTU master/slave
• IC695CMM004: 4-port serial communications module, standard temperature range, multi-protocol
• IC695CMM004LT: 4-port serial communications module, extended temperature variant (-40°C to +70°C), RS-232/RS-485, supports SNP, SNPx, Modbus RTU, RTU master
• IC695ETM001: 10/100 Mbps Ethernet module, SRTP, Modbus TCP, EGD
• IC695PNC001: PROFINET IO Controller, 128 IO devices, 2-port managed switch
• IC695EIS001: EtherNet/IP Scanner module, 256 connections

CPU Modules

• IC695CPU310: 300 MHz CPU, 10 MB user memory, single Ethernet port
• IC695CPU315: 300 MHz CPU, 32 MB user memory, dual Ethernet
• IC695CPU320: 1 GHz CPU, 64 MB user memory, redundancy-capable
• IC695CPE330: Dual-core CPU, 64 MB, embedded dual Ethernet, USB programming port
• IC695CPE400: Quad-core CPU, 128 MB, advanced motion and process control

Discrete I/O Modules

• IC695MDL654: 16-point 24 VDC positive logic discrete input module
• IC695MDL664: 16-point 24 VDC discrete output module, 0.5A per point
• IC695MDL740: 32-point 24 VDC discrete input, high-density
• IC695MDL752: 32-point 24 VDC discrete output, high-density

Analog I/O Modules

• IC695ALG600: 8-channel analog input, 4–20 mA / 0–10 V, 16-bit resolution
• IC695ALG608: 8-channel analog input with HART pass-through
• IC695ALG704: 4-channel analog output, 4–20 mA / 0–10 V
• IC695ALG728: 8-channel analog output, high-resolution

Power Supply Modules

• IC695PSA040: 40W AC/DC power supply, 120/240 VAC input
• IC695PSD040: 40W DC power supply, 24 VDC input
• IC695PSA140: 40W AC power supply with diagnostics

Sourcing Hard-to-Find & Obsolete PACSystems RX3i Parts

GE's PACSystems RX3i platform entered its mature lifecycle phase in the mid-2010s. While Emerson (the current platform steward) continues to offer select modules under active support, a significant portion of the catalog — including early CPU variants (IC695CPU310, IC695CPU315), legacy communications modules (IC695CMM002, IC695CMM004), and first-generation analog I/O — has transitioned to limited availability or end-of-life status.

DriveKNMS maintains a dedicated inventory of RX3i spare parts sourced from decommissioned plant assets, authorized surplus channels, and factory-refurbished stock. For the IC695CMM004LT specifically, DriveKNMS holds tested units with full functional verification against GE's serial communications protocol stack. All units are supplied with a 12-month warranty and traceable documentation. For plants operating under IEC 61511 or ISA-84 functional safety requirements, DriveKNMS can provide module-level test records on request.

Quality Control for the PACSystems RX3i Range

RX3i modules use a proprietary high-speed backplane bus (CSST — Common Serial System Transport) operating at 40 Mbps. Functional verification of communications modules such as the IC695CMM004LT requires active backplane enumeration, not bench-level power-on testing alone. DriveKNMS performs the following verification steps for all RX3i communications modules:

• Backplane insertion test using a reference IC695CHS012 chassis with IC695CPU320 host CPU
• Port-level RS-232 and RS-485 loopback verification at 9600, 19200, and 115200 baud
• Modbus RTU master/slave transaction test using a calibrated Modbus simulator
• SNP protocol handshake verification with GE Proficy Machine Edition 9.x
• Thermal cycling inspection for extended-temperature (LT) variant compliance
• Firmware version audit and comparison against GE SIM (Software Information Manual) revision history

© 2026 DriveKNMS. All trademarks belong to their respective owners. Specifications are for reference only and subject to change without notice. Verify all parameters against official documentation before installation.