I/O modules

High-Performance CPU for Series 90-70 GMR Systems

The GE IC697CPM790 central processing unit serves as the primary controller for Series 90-70 GMR (Genius Modular Redundancy) systems. This module executes user logic, processes I/O signals, and manages redundant operations in critical control applications. Emergency shutdown systems and fire and gas detection networks rely on this CPU for uninterrupted, fail-safe operation .

Processing Power and Memory Architecture

This CPU module features a 64 MHz 80486DX2 microprocessor with a 32-bit floating-point coprocessor for complex calculations . The unit provides 1 MB of battery-backed CMOS RAM, with 512 KB available for user programs and data storage . A dedicated flash memory stores the operating system firmware, enabling serial port updates without module removal . Furthermore, the processor executes Boolean functions in 0.4 microseconds, ensuring fast scan cycles .

Triple Modular Redundancy and Fault Tolerance

The GE IC697CPM790 implements triple modular redundancy (TMR) architecture for mission-critical applications . Three independent CPUs run concurrently and vote on outputs, ensuring seamless failover upon single-point failures . A standalone C program provides the autotest and synchronization routines essential for TMR operation . Additionally, the module supports hot-standby configurations with a 100 ms switchover time for maximum uptime .

Physical Design and Environmental Ratings

This CPU module occupies a single slot in the Series 90-70 rack and requires installation in slot 1 of the CPU chassis . The unit requires forced-air cooling when ambient temperatures exceed 40°C, with a 70 CFM fan recommended below the module . Four green LEDs indicate RUN, STOP, BATT, and FAULT status for immediate visual diagnostics . Furthermore, the module includes a three-position run/stop switch and a memory protection keyswitch for security .

System Integration and Configuration

You can install this CPU module in any Series 90-70 rack (IC697CHS750, 782, 783, 790, or 791) . The module communicates with I/O and option modules via the VME C.1 standard backplane . Users program the CPU using Logicmaster 90-70 or Proficy Machine Edition software over the built-in RS-485 SNP port or Ethernet TCP/IP . Moreover, the module supports floating-point calculations and configurable data and program memory allocation.

Applications and Lifecycle Considerations

The GE IC697CPM790 is specifically designed for emergency shutdown (ESD), fire and gas, and other critical control applications requiring high reliability . Common deployments include power generation, oil and gas, chemical processing, and water treatment facilities . This product has entered its end-of-life transition phase, making strategic spare stocking advisable for existing installations . Always verify system compatibility and firmware revisions before deployment.

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