GE Fanuc IC697CPM790-GD CPU Module

GE Fanuc IC697CPM790-GD Series 90-70 Central Processor Unit

The GE Fanuc IC697CPM790-GD is a Central Processing Unit (CPU) designed for the Series 90-70 Programmable Logic Controller platform. Powered by an Intel 64 MHz 80486DX2 32-bit floating-point microprocessor, the IC697CPM790-GD delivers rapid deterministic execution (0.4 µs per Boolean function) specifically engineered to execute complex algorithms in safety-critical, high-availability installations.

This module natively supports Triple Modular Redundancy (TMR) architectures when integrated with a standalone C application environment and Genius I/O networks (IC660/IC661), making it a standard automation core in marine propulsion control, emergency shutdown (ESD), fire & gas detection, turbine governors, and offshore power generation systems. The IC697CPM790-GD features 1 Mbyte of battery-backed CMOS RAM (with up to 512 Kbytes allocatable to user ladder logic/data registers), an onboard calendar clock, hardware key-switch memory protection, and a front-panel 15-pin D-sub RS-485 serial communication port.

Model Details

• Manufacturer: GE Fanuc
• Product Line: Series 90-70 PLC
• Model: CPM 790
• Exact MPN / Catalog Number: IC697CPM790-GD
• Hardware Revision: GD (Compatible with earlier revision backplanes and firmware revs)
• Form Factor: Single-slot VMEbus C.1 Eurocard standard

Technical Specifications

Compatibility

• Base Racks / Chassis: GE Series 90-70 VME chassis including IC697CHS750 (5-slot), IC697CHS782 / IC697CHS783 (9-slot), and IC697CHS790 (17-slot base racks) — occupies Slot 1 exclusively.
• Power Supply Modules: IC697PWR711 (55W standard rack power supply) and IC697PWR724 (High-capacity 100W/120W power supply).
• Genius Bus Controllers: IC697BEM731 for integration with Genius I/O blocks (IC660/IC661) in TMR and dual-redundancy layouts.
• Communication Modules: Ethernet interface IC697CMM742, Programmable Coprocessor IC697PCM711, and Bus Transmitter IC697BEM713.
• Programming Software: GE Fanuc Logicmaster 90-70 (MS-DOS), Control 90, VersaPro, and GE Fanuc / Emerson Proficy Machine Edition (PME).

Frequently Asked Questions

What is the exact difference between the standard IC697CPM782 and the IC697CPM790-GD?

The IC697CPM790 is a specialized 64 MHz high-performance CPU configured for native Triple Modular Redundancy (TMR) architectures and standalone C programming routines. While general-purpose 90-70 CPUs run simplex ladder applications, the CPM790 includes dedicated internal micro-routines to execute voted discrete and voted analog inputs across multiple Genius Bus Controllers.

Can I install the IC697CPM790-GD in any slot of the Series 90-70 rack?

No. The CPU module must always be installed in Slot 1 of the primary base rack (Rack 0). All subsequent slots are designated for communication adapters, coprocessors, and high-density I/O cards.

What should I do if the “OK” LED fails to turn solid after power-on self-test?

A blinking or unlit OK LED indicates a failed power-on self-test (POST). Check whether the rack power supply +5 VDC bus voltage is dropping below 4.90 VDC under load. If bus voltage is stable at 5.0 VDC and the LED continues blinking, access the controller through your programming software to extract the hardware diagnostic fault table.

Does the IC697CPM790-GD require programming jumper configuration?

No. The module is fully software-configured through programming tools such as Proficy Machine Edition or Logicmaster 90-70. There are no internal DIP switches or jumpers required for address or baud-rate setup.

How do I maintain program memory when replacing the battery?

The unit is built with dual battery connection terminals on the front assembly. Always connect the new charged battery to the open terminal before removing the discharged battery pack. This parallel connection prevents interruption of bias power to the volatile CMOS RAM chips.