GE IC693CPU311 — High-Reliability Compact CPU for Modicon 90-30 Series PLC Systems

Key Features

• 32-bit RISC processor — Delivers ~1.2 Klogic/sec performance; sufficient for small-to-mid complexity ladder logic tasks (e.g., conveyor sequencing or pump staging).
• 256 KB user memory (RAM + flash) — Enough for typical 90-30 applications; retains logic and data through power loss when a backup battery (IC693BEM331) is installed.
• Integrated RS-485 serial port — Supports SNP (Serial Network Protocol) for programming via Hand-Held Programmer or PC with IC693CBL302 cable — no extra interface cards needed.
• Real-time clock (RTC) — Built-in, battery-backed; enables time-stamped logging and scheduled routines (e.g., shift-based reporting or daily calibration triggers).
• Hot-swappable in backplane — You can replace it without powering down the entire rack — critical for minimizing downtime during maintenance windows.

Application Fields

This CPU shows up most often where long-term stability matters more than raw speed: municipal water pump stations running 20+ years on original hardware, food packaging lines needing consistent batch timing, and legacy HVAC controllers in university campuses or hospitals. A customer in Ohio recently used six IC693CPU311CAs to replace failing CPUs in their chilled water plant — they kept all existing I/O and wiring, cut commissioning time by ~60%, and avoided retraining operators on new HMI layouts. It’s not ideal for motion control or high-speed analog loops, but for discrete logic and basic PID regulation? It holds up.

GE IC693

Advantages & Value

From a procurement standpoint, this module makes sense when you’re balancing risk, cost, and compatibility. Unlike newer PACs or cloud-connected PLCs, the IC693CPU311CA doesn’t require cybersecurity audits, TLS configuration, or license renewals. Spare parts are still available — and because it’s been around since the early 2000s, there’s a large pool of used units and refurbished stock with traceable service history. In many cases, replacing an IC693CPU311 with a newer 90-30 CPU (like IC693CPU364) isn’t necessary unless you need Ethernet or larger memory. So if your project budget is tight and your application hasn’t changed much in a decade — this is often the pragmatic choice.

Installation & Maintenance

Install it in a NEMA 12 or IP54-rated cabinet with at least 50 mm clearance above/below for airflow. Avoid mounting near heat-generating devices like VFDs or transformers — thermal stress is the top cause of premature RTC or RAM failure. Always verify backplane voltage (5.0 ±0.25 VDC) before insertion. For maintenance: replace the lithium backup battery (IC693BEM331) every 3–5 years — even if the clock seems fine, degraded voltage can corrupt memory during brief outages. Firmware updates aren’t typical (firmware is stored in mask ROM), but always confirm version compatibility before loading logic from older software versions (e.g., Logicmaster 90 vs. Proficy Machine Edition). No routine cleaning is needed, but inspect the backplane contacts annually for oxidation — especially in humid or coastal environments.

Quality & Certifications

The IC693CPU311CA carries UL 508 (Industrial Control Equipment), CE (EN 61000-6-2/6-4), and RoHS compliance — verified on original production batches. While GE no longer manufactures new units, our tested and functionally validated units meet full OEM electrical and timing specs. Each unit ships with a 365-day warranty covering defects in materials and workmanship. We test every CPU for backplane communication, RTC accuracy, memory integrity, and boot sequence before shipping — and include a short test report upon request.