IC697CPU788 - 16 MHz, 32-Bit Expandable Central Processing Unit for Triple Modular Redundancy Systems

The IC697CPU788 is a 16 MHz, 32-bit central processing unit (CPU) designed for IC66 Triple Modular Redundancy (TMR) systems. It provides high availability for critical control applications, such as emergency shutdown (ESD) and fire and gas systems. This CPU supports 512 Kbytes of expandable memory and a range of input/output options for robust and reliable performance.

Key Features of IC697CPU788

    Single Slot CPU: The CPU occupies a single slot in the rack and supports 512 Kbytes of battery-backed expansion memory.
    I/O Capacity: Handles up to 352 discrete inputs/outputs in simplex mode and up to 1024 voted analog inputs in TMR systems.
    High-Speed Processing: Executes boolean functions in 0.4 microseconds with a 16 MHz 80386DX microprocessor.
    Redundancy Support: Provides triple modular redundancy to ensure high system reliability and fault tolerance.
    Programmed by MS-DOS/Windows: Compatible with both MS-DOS and Windows programming environments via Ethernet TCP/IP or SNP port.
    Battery-Backed Clock and Memory: Includes a battery-backed calendar clock and memory protection via keyswitch.
    Flexible Memory Configuration: Features configurable program and data memory, with up to 200 Kbytes available for user applications.
    Status Monitoring: Equipped with four status LEDs to monitor CPU operation, program status, and memory protection.

Triple Modular Redundancy (TMR)

The IC697CPU788 is a crucial component for Triple Modular Redundancy (TMR) systems, which are commonly used in critical applications like emergency shutdowns and fire detection. The CPU must operate with C program blocks to execute TMR operations, ensuring redundancy and fault tolerance. A typical TMR system configuration involves three PLCs, each handling redundant input and output channels, and continuously verifying the integrity of the signals.

Memory and Protection

    Expandable Memory: The CPU features an expansion memory board that provides 512 Kbytes of CMOS RAM, up to 200 Kbytes of which can be allocated for user applications. The memory is battery-backed to ensure data retention even in the event of a power failure.
    Memory Protection: The memory protect keyswitch ensures that data and configuration are secured from unauthorized changes, with access limited to authorized personnel via a parallel programmer.

Installation and Configuration

The IC697CPU788 is easy to install, requiring proper alignment of expansion memory and CPU connectors. Configuration is performed via MS-DOS or Windows-based programming software, with no need for DIP switches or jumpers. The system checks the configuration at power-up and reports any deviations to the CPU’s alarm processor function.

Installation Steps:

    Connect the battery to the module's connectors.
    Place the toggle switch in STOP mode and ensure the keyswitch is set to Memory Protection OFF.
    Install the CPU in slot 1 of rack 0, ensuring the rack power is off.
    Power up the module, and check the status LEDs for diagnostics. After successful diagnostics, the CPU is ready for programming.

Communication Ports

    RS-485 Serial Port: Provides communication between the CPU and a programmer or other serial devices using RS-485 compatible connections.
    Parallel Programmer Interface: The Bus Transmitter Module (IC697BEM713) connects to the programmer for parallel programming, especially for MS-DOS users.
    Ethernet TCP/IP: Optional Ethernet connectivity is available with the installation of an Ethernet Interface Module (IC697CMM741/742) to enable remote programming and control over TCP/IP.

Conclusion and Recommendations

The IC697CPU788 offers a robust and reliable solution for critical control systems requiring high availability through triple modular redundancy. Its expandable memory, high-speed processing, and fault-tolerant architecture make it ideal for applications where system failure is not an option. By supporting multiple I/O configurations and secure memory protection, this CPU ensures seamless control even in the most demanding environments.

For critical industries like oil and gas, power generation, or emergency systems, the IC697CPU788 provides the reliability and redundancy needed to keep systems running smoothly and safely.

>> GE Fanuc IC697CPU788 User manual (pdf)

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