GE IC697CPM790 PROGRAMMABLE LOGIC CONTROLLER CENTRAL PROCESSING UNIT

TECHNICAL SPECIFICATIONS

Manufacturer: GE Fanuc Automation (now Emerson Automation)
Series: Series 90-70
Product Type: Central Processing Unit – CPU with Triple Modular Redundancy support
Slot Width: Single slot

PROCESSOR:

• Microprocessor: Motorola 80486DX2

• Clock Speed: 64 MHz

• Architecture: 32-bit floating point processor

• Boolean Execution Rate: 0.4 microseconds per function

• Arithmetic Support: Floating point calculations

MEMORY:

• Total Battery-Backed RAM: 1 MB

• User Program Memory: Up to 512 KB available for ladder diagram application program

• Data Memory: Configurable allocation

• Memory Protection: Battery-backed with calendar clock

• Battery Life: 10 years at 20°C storage; memory retention of 6 months without power

DISCRETE I/O CAPACITY:

• Simplex Mode: Up to 12,000 discrete inputs and outputs in any combination

• Voted Redundant Mode: 2,048 voted discrete inputs

• Voted Redundant Mode: 2,048 voted discrete outputs

ANALOG I/O CAPACITY:

• Simplex Mode: Up to 8,000 analog inputs and 8,000 analog outputs

• Voted Redundant Mode: 1,024 voted analog inputs

COMMUNICATION PORTS:

• One 15-pin sub-D connector supporting RS-422 and RS-485 serial communication

• Compatible with SNP (Series Ninety Protocol), Modbus RTU, and programming interfaces

• Optional expansion for Ethernet, Genius Bus, and Profibus-DP via additional modules

POWER REQUIREMENTS:

• Backplane Voltage: 5 Volts DC

• Backplane Current Draw: 3.3 Amps maximum

• Maximum Power Dissipation: 6.8 Watts

OPERATING ENVIRONMENT:

• Forced Air Cooled: 0°C to 60°C

• Without Forced Air Cooling: 0°C to 40°C

• Storage Temperature: -40°C to +100°C

PHYSICAL DIMENSIONS:

• Width: 1.0 inch (25.4 mm) – single slot

• Height: 9.5 inches (241.3 mm)

• Depth: 8.5 inches (215.9 mm)

• Weight: Approximately 1.36 kg

STATUS INDICATORS:

• Four green status LED indicators

• Three-position operation mode control switch (RUN/STOP)

• Password-protected machine access control

REDUNDANCY ARCHITECTURE

Triple Modular Redundancy Configuration:
The IC697CPM790 supports full TMR implementation consisting of three separate PLC racks, each containing one CPU module, three independent Genius I/O buses, triple input sensors, and triple output loads . This architecture ensures that a single point of failure does not disrupt system operation. The TMR setup requires a Standalone C program to be included as part of the loaded application, which provides the operating and autotest routines essential for redundant operation .

Redundancy Specifications:

• Redundancy Type: Triple Modular Redundancy

• Switching Time: Less than 10 milliseconds

• System Availability: Greater than 99.999%

• Voting Capability: 2,048 voted discrete inputs; 2,048 voted discrete outputs; 1,024 voted analog inputs

PROGRAMMING AND SOFTWARE COMPATIBILITY

Programming Software:

• MS-DOS based programming software release 3.0 or later

• Windows 95 or Windows NT over Ethernet TCP/IP

• Windows-based programming applications

Programming Languages Supported:

• Ladder Diagram

• Function Block Diagram

• Structured Text

Communication for Programming:

• Direct connection via RS-485 15-pin port

• Requires RS-422/RS-485 to RS-232 converter for standard PC connection (IC690ACC900 or IC690ACC901)

• Ethernet connectivity with TCP/IP for Windows-based programming

SYSTEM COMPATIBILITY

Compatible Backplanes:

• IC697CHS750

• IC697CHS782

• IC697CHS783

• IC697CHS790

• IC697CHS791

Compatible I/O Systems:

• Series 90-70 I/O modules

• GE Fanuc Versamax I/O modules

• Genius I/O bus interfaces

FUNCTIONAL FEATURES

Triple Modular Redundancy Architecture
The IC697CPM790 is specifically designed to operate within a TMR configuration, providing three complete sets of control hardware that vote on all critical inputs and outputs. This architecture eliminates single points of failure and enables the system to continue operating normally even when one of the three modules fails .

High-Speed Boolean Processing
With a boolean execution rate of 0.4 microseconds per function, the 64 MHz 80486DX2 processor delivers the computational performance required for high-speed closed-loop PID control, complex ESD logic, and demanding industrial automation tasks .

Configurable Memory Architecture
The 1 MB battery-backed RAM allows flexible allocation between program and data storage, with up to 512 KB dedicated to the user ladder diagram application. This configuration flexibility enables optimization for different application requirements .

Robust I/O Handling Capabilities
The CPU supports extensive I/O configurations ranging from 12,000 discrete points in simplex mode to voted configurations of 2,048 discrete inputs and outputs in redundant mode. Analog handling includes up to 8,000 analog points in simplex mode and 1,024 voted analog inputs in redundant configurations .

Battery-Backed Calendar Clock
An integrated real-time clock with battery backup maintains accurate time and date information through power cycles. The clock provides 3.5 seconds per day accuracy with 0.01% internal time precision, essential for time-stamped events and scheduled operations .

Integrated Serial Communication
The built-in 15-pin RS-422/RS-485 serial port supports SNP protocol for programming and monitoring, as well as Modbus RTU for connectivity with third-party devices. This allows direct connection to operator interfaces and other serial devices without additional communication modules .

Security and Access Control
Password protection prevents unauthorized access to configuration data and application logic. The three-position mode control switch provides physical control over CPU operational state, allowing operators to select between RUN, STOP, and other operational modes .

Real-Time Clock Precision
The internal calendar clock delivers 3.5 seconds per day timing accuracy with 0.01% internal precision, enabling precise time-based control functions and event logging .

APPLICATION SCENARIOS

Emergency Shutdown Systems
The IC697CPM790 is specifically designed for Emergency Shutdown applications where safety and reliability are paramount. In oil and gas facilities, chemical plants, and power generation stations, the TMR architecture ensures that critical safety functions remain operational even if one control path fails. The CPU continuously monitors process conditions and initiates safe shutdown sequences when dangerous conditions are detected .

Fire and Gas Detection Systems
For fire protection and gas detection applications, the module provides the high reliability required for life safety systems. The TMR configuration with triple voting ensures that spurious alarms are minimized while maintaining genuine threat detection. The CPU processes inputs from flame detectors, gas sensors, and smoke detectors, coordinating alarms and suppression systems .

Turbine and Compressor Control
Gas compression stations and turbine control applications demand continuous operation with zero tolerance for unplanned shutdowns. The IC697CPM790 provides the computational power for complex speed control algorithms while the redundant architecture ensures uninterrupted operation during maintenance or component replacement .

Power Generation Facilities
Electrical power plants require control systems with high availability to maintain grid stability. The IC697CPM790 can be deployed to control boilers, steam turbines, and generator synchronization equipment. The TMR architecture supports online maintenance and repairs without taking the control system offline .

Pipeline Monitoring and Control
Oil and gas pipeline stations distributed across long distances benefit from the IC697CPM790 fault-tolerant design. The CPU processes flow measurements, pressure readings, and valve positions while maintaining continuous operation through any single component failure .

Refinery Process Control
Petroleum refineries contain continuous processes that cannot tolerate control system downtime. The IC697CPM790 provides the processing capability for complex fractionation column control, catalytic cracking unit management, and product blending operations while maintaining the high reliability required for hazardous environments .

Chemical Processing
Chemical manufacturing facilities require precise control of reactions, temperatures, and flows with fail-safe operation. The IC697CPM790 TMR architecture supports Safety Integrity Level requirements while providing the analog I/O capacity needed for continuous process control .

CRITICAL OPERATIONAL REQUIREMENTS
The IC697CPM790 will not operate unless a Standalone C program is included as part of the loaded application. This program provides the TMR operating and autotest routines essential for redundant operation. For simplex mode applications not requiring TMR, this requirement still applies and the Standalone C program must be present .

PRODUCT LIFECYCLE STATUS: Discontinued – Legacy product. Availability through authorized distributors and aftermarket suppliers.