GE Fanuc IC693CPU372 Central Processing Unit

The GE Fanuc IC693CPU372 is a high-performance CPU module for the Series 90-30 programmable logic controller platform. This module serves as the central processing unit for industrial automation systems requiring robust logic execution, fast I/O scanning, and extensive memory capacity. Powered by an Intel 386 processor running at 80 MHz, the IC693CPU372 delivers significant processing power for complex control applications including batch processing, material handling, and machine tool control. The module supports up to 6,000 inputs and outputs, making it suitable for medium to large-scale automation projects. The CPU incorporates floating point math capability, a real-time clock, and a built-in RS-232/485 serial port for programming and communication. It is compatible with the full range of Series 90-30 I/O modules and can be expanded using remote I/O networks such as Genius and Profibus DP.

Technical Specifications

The IC693CPU372 features a user memory of 240 KB, providing ample space for ladder logic programs, configuration data, and register storage. Execution speed for bit instructions is 0.15 µs per contact, while word instructions execute at 0.74 µs per operation. The maximum discrete I/O capacity is 4,096 inputs and 4,096 outputs (total 8,192 points), with a maximum of 2,048 analog I/O channels. The CPU includes a built-in floating point processor (math coprocessor) for efficient handling of real-number calculations. The serial communication port (COM1) is RS-232/485 configurable, supporting SNP (Series Ninety Protocol), RTU, and Modbus master/slave protocols. The module also features a second port (COM2) that can be configured as an additional RS-232 or as a data port for external devices. The CPU includes a real-time clock with a battery backup. Power consumption from the backplane is 5 V DC at 1.2 A. The module is housed in a single-slot form factor compatible with Series 90-30 racks (5-slot, 10-slot, or expansion racks). Operating temperature range is 0°C to 60°C.

Key Features

• 80 MHz Intel 386 processor with floating point coprocessor

• 240 KB user memory (battery-backed RAM) for ladder logic and data

• Supports up to 8,192 discrete I/O and 2,048 analog I/O channels

• Two built-in serial ports: RS-232/485 (programming/communication) and RS-232

• SNP, Modbus RTU master/slave, and CCM protocols supported

• Floating point math, real-time clock, and watchdog timer

• Supports Genius, Profibus DP, and Ethernet remote I/O networks (via optional modules)

• Compatible with all Series 90-30 I/O and option modules

• Single-slot design for space-efficient installation

• Battery-backed RAM retains program and data during power loss

Memory and Data Storage

The 240 KB of user memory is divided into several areas: program memory (ladder logic, function blocks, and structured text), register memory (holding registers for data storage), and system memory (configuration and I/O tables). The battery-backed RAM retains all program and register data during power outages. The battery life is typically 5 years. An optional EEPROM memory card can be used for permanent storage of the user program, allowing the CPU to automatically reload the program after a complete power loss without requiring a programming device. The CPU supports up to 999 program blocks (subroutines) and 255 function blocks. Data can be stored in up to 2,048 analog input registers and 2,048 analog output registers, as well as 8,192 discrete inputs and 8,192 discrete outputs internally.

Communication Capabilities

The IC693CPU372's built-in COM1 port (RS-232/485) supports multiple protocols. SNP (Series Ninety Protocol) is the standard protocol for programming and HMI communication using GE Fanuc's Logicmaster or Proficy Machine Edition software. The Modbus RTU master capability allows the CPU to read/write data from Modbus RTU slave devices such as drives, power meters, and temperature controllers. As a Modbus RTU slave, the CPU can be polled by a Modbus master (e.g., SCADA system). CCM (Computer Communications Module) protocol enables communication with host computers. The COM2 port (RS-232) is typically used as a programming port or can be configured for SNP or Modbus RTU slave. For high-speed networking, optional modules can be added to the Series 90-30 rack, including Ethernet (TCP/IP, Modbus TCP, SRTP), Profibus DP master/slave, Genius (GE Fanuc's proprietary I/O bus), and DeviceNet modules.

Programming and Software

The IC693CPU372 is programmed using GE Fanuc Proficy Machine Edition (versions 5.0 and later) or Logicmaster 90-30 software. Supported languages include Ladder Diagram (LD), Structured Text (ST), Function Block Diagram (FBD), and Sequential Function Chart (SFC). The CPU supports advanced instructions such as PID control, matrix operations, table functions, and trigonometric calculations. The built-in floating point math capability allows direct handling of real numbers without scaling. Online editing is supported, allowing program changes while the CPU is running. The CPU also supports a user-defined configuration of the serial ports via the programming software. The diagnostic capabilities include a built-in fault history log and online monitoring of I/O and registers.

Applications

The IC693CPU372 is suitable for industrial applications such as packaging machinery (filling, sealing, labeling), material handling systems (conveyors, sorters, palletizers), machine tools (CNC controllers, lathe automation), batch processing (chemical, pharmaceutical), water and wastewater treatment (pump control, filtration), and building automation (HVAC, lighting). Its large memory capacity and fast execution speed allow it to handle complex control algorithms and extensive data logging. The Modbus RTU capability simplifies integration with third-party instrumentation. The CPU is often used in installations requiring remote I/O networks, where it serves as the master controller for Genius or Profibus DP remote racks.

Installation and Maintenance

The IC693CPU372 installs into any slot of a Series 90-30 rack (IC693CHSxxx). Ensure the rack's power supply is sized appropriately to handle the CPU and all I/O modules. The CPU includes a lithium battery (type BR-2/3A) that must be replaced periodically (typically every 5 years). Battery replacement can be performed with the CPU powered on to avoid data loss. The CPU includes a multi-turn potentiometer for adjusting the real-time clock. Status LEDs on the front panel include: PWR (power), RUN (CPU in run mode), OK (CPU healthy), and I/O (I/O bus active). The module has a memory protect switch that prevents accidental program overwrites. For firmware updates, the CPU can be upgraded via the serial port using the appropriate update utility.

Conclusion

The GE Fanuc IC693CPU372 CPU module provides a powerful, feature-rich control solution for Series 90-30 PLC systems. With its 80 MHz processor, 240 KB memory, floating point math, and built-in serial communications, it remains a viable choice for maintaining and expanding existing GE Fanuc installations or for new projects requiring compatibility with the Series 90-30 platform.