GE Fanuc Series 90-70 Modules - HE693THM884

Technical Dossier

Product Details And Specifications

GE Fanuc Series 90-70 Technical Notes

The GE Fanuc Series 90-70 (also referenced as the GE 90-70 or IC697 / HE693 platform) is a rack-based programmable logic controller system that has accumulated significant installed base across global heavy industry sectors including petrochemical refining, nuclear power generation, offshore oil & gas platforms, pulp and paper mills, and large-scale water treatment facilities. Its modular VMEbus-derived backplane architecture, deterministic scan cycle performance, and broad I/O density made it the preferred DCS/PLC hybrid platform for process-critical applications requiring high channel counts and long operational continuity. Many installations commissioned in the 1990s and early 2000s remain in active service, making lifecycle parts sourcing a primary operational concern for plant maintenance engineers worldwide.

The Evolution of Series 90-70 Architecture

The Series 90-70 platform was introduced by GE Fanuc Automation in the late 1980s as a high-end successor to the Series Six and Series Five PLC families. The original HE693 product line (manufactured under the Horner Electric / GE collaboration) established the foundational rack, backplane, and I/O module form factor. The IC697 designation later became the primary GE Fanuc catalog prefix as the product line was consolidated under GE Fanuc's global manufacturing and distribution structure.

The architecture is built around a parallel VMEbus backplane supporting up to 21 slots per rack (IC697CHS750 / IC697CHS782), with a dedicated CPU slot and mixed analog/digital I/O population. CPU evolution progressed from the IC697CPU731 (early 386-class processor, 512KB user memory) through the IC697CPU771 and IC697CPU781 (Pentium-class, expanded memory, Ethernet-ready) to the IC697CPU788 and IC697CPM790 (the final production CPUs with integrated Ethernet and expanded program store). Communication options expanded from serial RS-232/RS-485 (IC697CMM711) to full TCP/IP Ethernet (IC697ETM001) and Genius Bus Controller (IC697BEM711) integration.

The Series 90-70 platform entered its end-of-life phase progressively between 2010 and 2018. GE (later rebranded as GE Vernova / Emerson after the Automation & Controls divestiture) formally discontinued new production of most IC697 and HE693 modules. The recommended migration path is to the PACSystems RX7i platform (IC698 series), which offers physical rack compatibility with select 90-70 I/O modules via the IC698CHS009 adapter rack, providing a controlled migration route without full I/O rewiring.

Series 90-70 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly sourced modules within the GE Fanuc Series 90-70 platform. Modules are classified by functional category.

CPU & Controller Modules

• IC697CPU731: Series 90-70 CPU, 512KB user memory, RS-232 port, early-generation processor module.
• IC697CPU771: Enhanced CPU, 2MB user memory, floating-point math, expanded I/O scan capacity.
• IC697CPU781: High-performance CPU, 6MB user memory, dual RS-232, supports large program stores.
• IC697CPU788: Advanced CPU with integrated 10/100 Ethernet port, 10MB user memory.
• IC697CPM790: Final-generation CPU module, 32MB memory, dual Ethernet, hot-standby redundancy capable.

Analog Input Modules

• IC697ALG230: 16-channel analog voltage/current input, ±10V / 4–20mA, 12-bit resolution.
• IC697ALG320: 8-channel analog input, high-speed conversion, isolated channel architecture.
• HE693THM884: 4-channel thermocouple input module, supports J/K/T/E/R/S/B type thermocouples, cold junction compensation, 16-bit resolution — the current listing SKU.
• IC697ALG440: 16-channel analog input, current/voltage configurable per channel, 16-bit ADC.

Analog Output Modules

• IC697ALG390: 8-channel analog voltage output, ±10V, 12-bit DAC, individual channel enable.
• IC697ALG432: 4-channel analog current output, 4–20mA, 12-bit resolution, short-circuit protected.

Digital Input Modules

• IC697MDL240: 32-channel 24VDC digital input module, sink/source configurable, LED status per channel.
• IC697MDL250: 16-channel 120VAC digital input, optically isolated, zero-crossing detection.
• IC697MDL340: 32-channel 24VDC digital input, high-density, group isolated.

Digital Output Modules

• IC697MDL940: 32-channel 24VDC digital output, 0.5A per channel, short-circuit protection.
• IC697MDL653: 16-channel relay output module, Form C contacts, 2A per channel, 120/240VAC rated.

Communication & Network Modules

• IC697CMM711: Serial communications module, RS-232/RS-485, supports SNP/SNPX and Modbus RTU protocols.
• IC697BEM711: Genius Bus Controller, manages up to 32 Genius I/O blocks on a single bus segment.
• IC697ETM001: Ethernet TCP/IP module, 10BaseT, SRTP and Modbus TCP server, web diagnostics.

Power Supply Modules

• IC697PWR710: 120/240VAC input power supply, 30W output, standard rack power for 90-70 systems.
• IC697PWR724: 24VDC input power supply, 30W, for DC-powered panel installations.

Quality Control for the Series 90-70 Range

Series 90-70 modules present specific test challenges due to their VMEbus backplane communication protocol, analog signal chain complexity, and age-related component degradation patterns. DriveKNMS applies a structured test protocol to all IC697 and HE693 modules prior to shipment.

Each module undergoes visual inspection for capacitor bulge, PCB corrosion, and connector pin integrity. Functional testing is performed in a live Series 90-70 rack using a reference IC697CPU781 or IC697CPU788 CPU with verified test ladder logic. Analog modules including the HE693THM884 are tested across the full input range for each channel, with cold junction compensation accuracy verified against a calibrated reference source. Digital I/O modules are cycled through all channels under load. Communication modules are tested for bus arbitration, protocol handshake, and data integrity under continuous traffic. All units are burned in for a minimum of 24 hours before final inspection and packaging.