GE IC693PCM300N Programmable Coprocessor Module (PCM)

Description

In many industrial automation and process control applications built around the GE Series 90-30 PLC platform, engineers need to offload complex tasks from the main CPU to maintain scan times, handle communication-intensive operations, or implement custom logic without bloating the primary ladder program. Standard PLC processing can become strained when dealing with protocol conversions, data logging, mathematical computations, report generation, or interfacing to third-party devices via serial links. This is especially true in legacy systems where adding another full controller isn’t practical due to rack space, cost, or integration complexity.

GE IC693PCM300N directly tackles these limitations as a high-performance Programmable Coprocessor Module (PCM) designed specifically for Series 90-30 Modular CPUs. It runs independently, executing user-written programs in MegaBasic or C while communicating seamlessly with the PLC CPU over the backplane. This offloading preserves deterministic PLC scan cycles for core control tasks, while the coprocessor manages heavier data handling, custom protocols, or supervisory functions. GE IC693PCM300N becomes essential in setups requiring robust serial communications (like Modbus RTU master/slave or CCM), data buffering, or application-specific algorithms—helping achieve higher system throughput, better response to field devices, and easier maintenance of specialized code in industrial automation environments.

The GE IC693PCM300N operates as an intelligent coprocessor within a Series 90-30 rack, occupying any available slot (except in embedded CPU models or expansion/remote racks). It features its own microprocessor, onboard RAM (with battery backup), and two configurable serial ports (Port 1 and Port 2) accessed via a single front-panel connector. These ports support RS-232/RS-485 configurations for point-to-point or multi-drop networks, enabling the module to act as a Modbus RTU master/slave, CCM device, or host for custom MegaBasic/C applications.

Interfacing with the main PLC occurs transparently through shared memory registers—%R, %AI, %AQ, %I, %Q—allowing bidirectional data exchange without additional ladder logic for basic transfers. The module supports protocol drivers like Modbus and CCM natively, plus user-developed code for tasks such as ASCII messaging, barcode reading, or RTU polling. Status LEDs (COPROC OK, US1, US2, BD OK, P1 OK, P2 OK) provide clear diagnostics, and a RESTART pushbutton enables quick module resets without power cycling. In the automation stack, GE IC693PCM300N sits alongside the CPU as a co-processing resource, ideal for augmenting control with computation-heavy or communication-focused duties while keeping the primary logic simple and fast.

Selecting GE IC693PCM300N delivers practical improvements in system architecture and performance. By offloading non-critical but resource-intensive tasks, it ensures the main CPU remains focused on high-priority control loops, resulting in more consistent scan times and reduced risk of overruns in time-sensitive processes. The dual serial ports and protocol support simplify connections to HMIs, SCADA systems, scales, drives, or remote terminals, often eliminating the need for external protocol converters or additional hardware.

The module’s programmable flexibility—via MegaBasic for straightforward scripting or C for optimized performance—allows engineers to encapsulate custom logic once and reuse it across projects, cutting development time and standardizing maintenance procedures. Built-in diagnostics and battery-backed memory provide confidence in data integrity during power events, while the ability to develop and download applications without halting the PLC minimizes production impact. In legacy Series 90-30 installations, GE IC693PCM300N extends system life by adding modern capabilities without full platform migration.

GE IC693PCM300N is commonly deployed in manufacturing plants for handling barcode scanning, weigh-scale integration, or printer/report generation in assembly or batch processes, where serial data must be processed without interrupting machine control. In water and wastewater facilities, it serves as a Modbus master polling remote sensors or RTUs, aggregating data for the central PLC while managing alarm buffering and timestamping. Oil & gas or material handling sites use it for custom ASCII protocol handling with legacy field devices, ensuring reliable communication in harsh, distributed environments that demand continuous uptime and precise data handling in process control setups.

Related or compatible products in the GE Series 90-30 family include:

• IC693PCM300 – Base version (often listed interchangeably; IC693PCM300N typically denotes a specific revision or packaging).
• IC693PCM301 – Higher-memory variant (192K total, 47K user MegaBasic) for larger programs or more data storage.
• IC693PCM311 – Highest-capacity model (640K total, 190K user) suited for complex applications or extensive code.
• IC693CPU364 – Modular CPU with embedded Ethernet, pairs well when combining coprocessor tasks with network needs.
• IC693CMM311 – Communications Coprocessor alternative focused on CCM/Modbus without full programming flexibility.
• IC693ACC301 – RS-485 adapter for PCM ports when multi-drop networks are required.
• IC693PWR330 – Recommended high-capacity power supply for racks including GE IC693PCM300N and multiple modules.
• IC693MDLxxx series – Standard I/O modules that work alongside the PCM in the same rack.

Before installing GE IC693PCM300N, ensure the rack uses a Modular CPU (CPU331 or higher; not compatible with embedded models like 311/313/323 or expansion racks). Verify backplane power capacity covers the module’s draw plus other components. Install the included lithium battery in the clip for RAM retention, and configure ports via jumpers or software for RS-232/RS-485 as needed. Use Proficy Machine Edition (or VersaPro) to develop/download MegaBasic/C applications and map registers—test communications offline first to avoid live system disruptions.

For ongoing maintenance, monitor the front LEDs: COPROC OK should be steady green; flashing or off indicates faults (check battery, configuration, or hardware). Inspect serial connectors quarterly for secure connections and corrosion, especially in dusty or corrosive areas. Periodically verify battery voltage (replace every 2–5 years) and review application logs via the development software. Run self-tests or restart the module during scheduled downtime if diagnostics show anomalies.