Description

Key Technical Specifications

Parameter	Value
Model	IC695CPU315 (catalog 1C695CPU315)
Manufacturer	GE Fanuc
Platform	PACSystems RX3i
Processor	1 GHz Intel Celeron-M
User Memory	20 MB RAM (battery-backed)
Flash Storage	20 MB
I/O Capacity	32K discrete bits / 32K analog words
Program Blocks	Up to 512 blocks, 128 KB max per block
Serial Ports	2 onboard — one RS-232 (9-pin), one RS-485 (15-pin)
Serial Protocols	SNP, Serial I/O, Modbus RTU master/slave
Programming Languages	Ladder (LD), Structured Text (ST), Function Block Diagram (FBD), plus C; SFC and IL not supported
Operating Temperature	0°C to 60°C
Backplane	Dual backplane bus; supports IC695* and IC694* modules
Battery Options	IC695ACC302 / IC693ACC302; not compatible with IC698ACC701

Product Introduction

A paper mill I know lost a Saturday shift because a RX3i CPU threw a battery fault at 2 a.m. and nobody had the spare on the shelf. The plant had the I/O spares. They didn’t have the CPU. That’s the whole reason you keep an IC695CPU315 on the rack shelf.This is the workhorse CPU of the GE Fanuc PACSystems RX3i line. 1 GHz Celeron-M, 20 MB of user memory, 20 MB of flash, and two onboard serial ports — one RS-232, one RS-485 — so you can talk to a legacy drive on one port and a Modbus RTU slave on the other without buying a CMM002. It handles up to 32K I/O operations per second and supports up to 512 program blocks at 128 KB each, which covers most mid-size process and material handling applications without breaking a sweat.Engineers pick it for one unglamorous reason: it accepts most older GE Fanuc Series 90-30 modules and expansion racks. That matters when you’re extending a 2005-era panel in 2026 and don’t have budget for a full I/O refresh. My honest note: this platform is long in the tooth. It works, but plan your exit — GE Vernova’s support runway for RX3i legacy CPUs is finite, and firmware revisions matter more than people admit.

Quality SOP & Tech Pitfalls

The Lab Report (SOP)Every unit gets the same treatment before it ships:

Visual / counterfeit check. Nameplate laser depth, PCB solder joints, capacitor bulging, any sign of board cleaning or reflow.
Live test on test rack. Seated in a spare RX3i chassis, 24 V DC supply, 24-hour soak. Program downloaded, run mode confirmed.
Port verification. Both serial ports exercised — RS-232 loopback, RS-485 Modbus RTU master test against a slave simulator.
Battery circuit check. IC695ACC302 or IC693ACC302 fitted and load-tested. Fluke 115 on the battery terminals.
Firmware version logging. Read via PAC Systems, recorded in the shipping report.
Anti-static sealing. ESD bag, desiccant, foam, serial-labeled.

No photo-only shipping. If I can’t hand you a test record, I don’t sell the module.The Engineer’s Warning (Pitfalls)Pitfall 1 — Firmware revision mismatch. The RX3i reference manual is explicit that features are gated on firmware — HART pass-through on CPU315, for example, requires firmware 8.50 or later. Drop in a module with older firmware and your function blocks won’t compile, or worse, will compile and behave differently. Record the firmware version of the CPU you’re replacing before you pull it.Pitfall 2 — The “-CD” suffix gamble. Suffix letters on GE parts often denote revision, region, or packaging. Two resellers I found list this part with completely different specs — one calls it a bus receiver for IC697 racks. Field disaster I watched happen: a buyer ordered “IC695CPU315” from a cheap listing, got a module that physically seated, and the rack threw a backplane config fault for six hours because the firmware and the project’s PAC Systems version didn’t line up. Photograph the nameplate. Send the photo. Get the firmware version in writing.

Installation & Configuration Guide

Phase 1 — Pre-Installation (⚠️)

Notify operations. Place the loop in manual or bypass per your MOC.
⚠️ De-energize the rack. Confirm 0 V at the power module output with a meter — not by panel LEDs.
Wait 60 seconds for bus capacitor discharge.
⚠️ Photograph the old CPU: nameplate, front serial cabling, and the PAC Systems project file. Export the project and note the firmware version.

Phase 2 — Removal
5. Disconnect the RS-232 and RS-485 cables. Label each with its port.
6. Release the module ejector levers evenly. Pull straight out — no prying against the backplane.
7. Inspect the slot and backplane connector for corrosion or bent pins.Phase 3 — Installation
8. Confirm the replacement’s firmware version matches your project before seating it. This single check prevents most startup failures on RX3i swaps.
9. Fit the battery pack (IC695ACC302 or IC693ACC302) if the old one was present.
10. Seat the module until the ejectors latch. Reconnect serial cables to the correct ports — RS-232 is 9-pin, RS-485 is 15-pin.Phase 4 — Power-On & Testing
11. Restore power. Confirm the CPU RUN LED and check for SYS FLT.
12. Download the project. Verify the firmware version reports as expected.
13. Confirm I/O modules come online with no bus faults.
14. Exercise the loop: force a known input, confirm output response, then return to automatic with operations’ sign-off.

Compatible Replacement Models

Model	Compatibility	Notes
IC695CPU315 (any suffix)	✅ Drop-in Replacement	Same hardware. Suffix differences are usually revision/packaging. Price spread is extreme — I’ve seen 99 to 999 listings for the same base number.
IC695CPU320 / CRU320	⚠️ Software Compatible	64 MB memory, same family. Requires project recompile and possibly a PAC Systems version upgrade. Estimate 4–8 hours engineering.
IC695CPE305 / CPE310 / CPE330	⚠️ Software Compatible	Different memory and port config (CPE330 has no serial ports). Logic recompile plus I/O remap. Budget 8–16 hours.
RX7i or newer platform	❌ Hardware Mod Required	New chassis, new I/O, full re-engineering. Only do this as a planned capital project — not as a failure workaround.

Frequently Asked Questions (FAQ)

“What does the ‘-CD’ suffix actually mean?”
Honestly? I don’t have a GE document that defines it. On GE parts, suffix letters typically denote hardware revision, region, or packaging variant — not a functional change. But since resellers list this part number with contradictory specs, don’t guess. Ask the supplier for a nameplate photo and confirm the base number is 1C695CPU315.“Can I hot-swap this safely?”
Not without redundancy. If you’re running a hot-standby pair, yes — swap the standby. Single CPU feeding a live process? No. Put the loop in manual, de-energize, and swap it properly. Hot-swapping a CPU into a running rack is how a 30-minute job becomes a shift-long outage.“Will my existing program load onto a replacement?”
Usually — if the firmware revision is compatible. That’s the “if” that bites people. Export the project, note the old CPU’s firmware version, and confirm the replacement matches or is newer. An older firmware version will reject newer function blocks.“Is this new or used?”
Assume surplus unless the supplier shows factory-sealed packaging with a legible date code. The RX3i CPU315 is a legacy part; genuine factory-fresh stock is scarce. Ask for the date code — if they can’t provide one, it isn’t sealed.“Why is the price so different between suppliers?”
Because the aftermarket for legacy GE parts is unregulated. I’ve seen listings from 99 to 999 for the same base model number, and one page describing it as an entirely different module type. Get three quotes, demand test records, and treat suspiciously low prices as a condition warning.“My CPU threw a battery fault. Is the CPU dead?”
Nine times out of ten, no — it’s the battery. Check IC695ACC302 or IC693ACC302 first and replace it. Note that IC698ACC701 is not compatible with this CPU. Only after a fresh battery and a confirmed 24 V supply do you start blaming the module.