GEIC630CPU301ASeries Three CPU / Programmer Unit — 4K Words CMOS RAM, 400 I/O Points, Built-In Ladder Programmer and Diagnostics

Product Description

What this part is

This is the CPU for a GE Fanuc Series Three programmable controller, and it is also the programmer. That combination is the whole point of the part and it is the thing most listings leave out. The IC630CPU301 contains the microprocessor that executes the ladder logic, scans the I/O and holds the user program — and on the same unit, a keypad and display for entering programs, editing them, adjusting timer and counter presets, monitoring coil and contact status, starting and stopping the program, and reading out error codes and diagnostic reports. On most PLC platforms of this era those are two purchases. On Series Three they are one.

Decoding the order code

IC630: GE Fanuc Series Three product line, distinct from IC610 Series One, IC600 Series Six and IC693 Series 90-30.

CPU: central processing unit; on this platform the CPU and programmer are the same module.

301: the 4K-word CPU / programmer unit.

A: hardware revision letter. Revision B (IC630CPU301B) is the other commonly traded revision; revisions in this family are functionally equivalent.

Also written IC630-CPU-301-A, IC630 CPU 301 A, IC630CPU301 and, in the shorthand many maintenance departments use, GE Series 3 CPU board.

Published specifications

User memory: 4096 sixteen-bit words (4K words) of CMOS RAM; optional EPROM module available separately.

Memory retention: on-board lithium battery, accessible under a plastic cover on the underside of the module.

Battery life: up to approximately 2 years under load, 8–10 years unloaded shelf life.

Maximum I/O: 400 discrete input and output points per system.

Internal relays: 368, of which 64 are retentive.

Timers and counters: 128.

Shift registers: up to 128 words.

Data registers: up to 128 words.

Program scan rate: 28.5 ms.

Base units per system: up to 3 — one CPU base unit plus up to two I/O base units.

Base unit sizes: 4-slot, 6-slot and 8-slot I/O module base units.

Maximum I/O modules: 8 per base unit, 24 per system.

System supply: external 115 VAC or 230 VAC, ±15%, selected by internal jumper.

Input frequency: 48–63 Hz.

Maximum load: 60 VA per base unit.

I/O expansion distance: up to 19 inches (approximately 50 cm) from the CPU base unit to the last I/O base unit.

Programming language: ladder.

Mounting data

Mounting position: the CPU position of the Series Three main base unit only; it cannot occupy an I/O slot and cannot go on an I/O base unit.

Handheld operation: the unit runs handheld on a 1.5 m CPU connector cable.

Battery location: the lithium cell holder sits under the plastic cover on the bottom of the module.

Supply selection: the base unit carries an internal 115/230 VAC jumper.

Diagnostics: the built-in diagnostic error code readout reports more detail than the base unit LEDs.

What these specs mean in practice

The I/O expansion figure catches people out. Series Three expansion is limited to about 19 inches total from the CPU base unit to the last I/O base unit. This is not a remote I/O architecture — the three base units are intended to sit side by side in the same enclosure. A drawing showing I/O racks in separate panels is not a Series Three installation.

The 1.5 m CPU connector cable is the feature that makes this unit pleasant to work with. Unplugged from the base unit and hung on the cable, it can be carried to the machine to watch contact states live rather than leaning into a panel. That is genuinely useful during commissioning and fault-finding, and it is why these units are still sought after by anyone maintaining Series Three plant.

4K words is small. A 28.5 ms scan is slow by modern standards. Neither matters for what Series Three was sold to do — small to medium sequential machine control, 400 points maximum — but both are hard ceilings with no upgrade path within the platform.

The lithium battery is the risk item on any surplus unit. Under load it lasts around two years, so a module that has been on a shelf for a decade has a flat cell and CMOS RAM contents cannot be assumed.

Quantity and configuration

CPU / programmer unit only, one unit per purchase. The 4-, 6- or 8-slot base unit, the input and output modules, the 1.5 m CPU connector cable for handheld operation, the optional EPROM memory module, a lithium battery, the I/O expander cable between base units, and the cassette tape unit, PROM writer and printer peripherals are each ordered separately. The base unit takes 115 or 230 VAC directly.

Interchange guidance

Search forms include IC630CPU301A, IC630CPU301, IC630-CPU-301-A, IC630 CPU 301 A, IC630CPU301B, GEC0IC630CPU301A and GE Series 3 CPU board. Revisions A and B interchange. Series Three, Series One, Series Six and Series 90-30 are entirely separate platforms with no shared modules — an IC610, IC600 or IC693 part number will not fit a Series Three base unit and vice versa. Series Three is long discontinued with no factory replacement; surplus, reman and board-level repair are the supply channels, and CPU / programmer units are the scarcest item in the family because every system needs exactly one and there was no separate programmer to cannibalise.