GE Fanuc IC693CPU331-AB Series 90-30 CPU Module

The IC693CPU331-AB is a single-slot modular central processing unit (CPU) for GE Fanuc Series 90-30 programmable logic controllers (PLCs). Built on an 80188 microprocessor operating at 10 MHz, it provides executing logic capabilities with a typical scan rate of 0.4 ms per 1K of Boolean logic. Designed for baseplate Slot 1 installation, it handles up to 512 discrete I/O points and includes a built-in serial port supporting SNP and SNP-X slave communications.

Architecture and Memory Allocation

The module comes equipped with 16 Kbytes of battery-backed RAM user memory to store user logic programs and configuration data. Optional non-volatile EPROM or EEPROM memory chips can be installed for program retention during extended outages.

Internal memory structures are categorized for system mapping, including 512 discrete inputs (%I), 512 discrete outputs (%Q), 128 words of analog inputs (%AI), and 64 words of analog outputs (%AQ). System logic resources include 1,280 bits of discrete global memory (%G), 1,024 internal coils (%M), 256 temporary coils (%T), 128 system status references (%S), 2,048 words of register memory (%R), 16 system registers (%SR), and up to 680 total timers and counters.

System Expansion and Communications

The CPU installs exclusively into Slot 1 of any Series 90-30 baseplate (5-slot or 10-slot). To expand system capacity beyond the local baseplate, the IC693CPU331-AB supports up to four expansion baseplates or four remote I/O baseplates.

Primary serial communications are provided through the D-sub connector on the system power supply, which links directly to the CPU backplane interface. This port operates under SNP and SNP-X slave protocols. For master protocol support (such as SNP/SNP-X master, CCM, or Modbus RTU), separate Communications Option Modules—such as the CMM (e.g., CMM301) or PCM modules—must be added to the rack.

Technical Specifications

Functional Features

• Override Support: Unlike fixed embedded CPUs in the Series 90-30 line, this modular CPU supports the Override function, allowing developers and operators to force I/O states during troubleshooting.
• Real-Time Clock: Includes a battery-backed internal clock for time-stamping events and handling time-based control routines.
• Multi-tasking Option: Compatible with State Logic Processor (SLP) modules to enable multi-tasking control architectures.

Frequently Asked Questions

Q: How do I access the built-in serial communication port on the IC693CPU331-AB? A: The serial port is accessed through the 15-pin D-sub connector located on the Series 90-30 PLC power supply module, which routes signals directly to the CPU across the backplane.

Q: Can the IC693CPU331-AB act as an SNP master on its native serial port? A: No, the native port only supports SNP slave and SNP-X slave protocols. Operating as an SNP master, CCM, or RTU master requires adding dedicated CMM or PCM option modules.