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Tech Support

GE Fanuc PLC Tech Support – FAQs – Series Three

Please click below to find the answers to our most Frequently Asked Questions (FAQ):

My Series Three PLC quit working; how do I troubleshoot the problem myself?

We offer copies of the manufacturer’s troubleshooting guides for the Series Three PLC available for in the Series Three documentation section. If you need additional help, our technical support staff is ready to assist you by phone at 1-866-599-6507 or through email to

How can I view, print, or change the ladder-logic program in my Series Three PLC?

Reviewing and editing the program stored in a Series Three CPU using the built-in display and keypad can often be frustrating because the LED display can only show one program instruction at a time. Thankfully GE produced a Portable Programmer unit that makes it easier for the user to visualize a PLC program by displaying several rungs of ladder-logic at once.

The Portable Programmer is an optional accessory to the Series Three, Series One, and Series One Junior PLCs that allows ladder-logic programs to be viewed, edited, and printed. With its 5-line, dot-matrix LCD display and rugged, industrialized enclosure, the Portable Programmer is a specialized ladder-logic programming device ideal for use in the field.

Program transfer and on-line monitoring are available through the Portable Programmer’s serial interface. Programs can also be transferred to and from the PLC using the unit’s built-in tape port. A printer port allows hard copies of programs to be printed to any parallel printer using the included cable. The part number for the Portable Programmer is IC610PRG110.

We also offer a kit which includes the Portable Programmer, a Series Three Program Pack (IC610PRG117), and a CD containing a complete set of manuals for the Series Three and Series One product families. More information on the kit is available on the Series Three documentation section.

Is there software I can run on a personal computer to communicate with a Series Three PLC?

No such software is currently available. Although the Series Three Programmable Controller User’s Manual refers to a program known as LogicMaster 3, this software was never released to market.

How can I create a backup copy of the program in my Series Three PLC?

The Series Three PLC was designed to allow permanent program backups to be stored on consumer-grade audio cassette tapes. The backup is created by transferring data to a cassette recorder through an audio cable connected to the Series Three CPU’s built-in tape port.

Almost any cassette recorder with a tone control and an external microphone input can be used, but we have put together a kit consisting of a compatible cassette recorder, batteries, and two cassette tapes. More information on the recorder is available by calling our sales representatives at 1-866-599-6507.

What does error code E21 on a Series Three PLC mean?

Error code E21 signifies a memory parity failure and is one of more frequently seen error codes on the Series Three PLC. This error is displayed when the program data stored in RAM has become corrupt and is no longer valid. It is common for this condition to occur following a temporary power outage in cases where the battery is too weak to retain the program stored in memory. The only way to resolve an E21 error is to reload or reenter the program. In rare circumstances, E21 can also indicate a hardware fault within the CPU itself. Our technical support staff can help you determine whether or not hardware replacement is warranted. We can be reached by phone at 1-+866-599-6507 or through email to For information on other error codes, please refer to “Series Three Error Code Definitions” available on the Series Three documentation section.

does error code E22 on a Series Three PLC mean?

For the Series Three PLC, error code E22 indicates that the backup battery in the CPU has reached the end of its useful life. The battery should be replaced as soon as possible to ensure that the ladder-logic program contained in the unit’s RAM will not be lost in the event of a power outage. The replacement part number is IC610ACC150.

What does error code E41 on a Series Three PLC mean?

Error code E41 is displayed when the Series Three CPU detects a change in I/O module configuration or if an error occurs when transferring data between I/O modules and the CPU. It is normal for this error code to appear whenever I/O modules are added or removed from the system, or when I/O modules are relocated from one slot to another in the base unit. In most circumstances, an E41 error can be cleared by placing the key switch on the front of the Series Three CPU in the RUN 1 position and pressing the SET key. If this procedure fails to clear the error, a fault may be present in the hardware of the CPU, one or more I/O modules, or the base unit. Our technical support staff will be glad to assist you in pinpointing the source of this and other Series Three PLC errors. We can be reached by phone at 1-866-599-6507 or through email to For information on other error codes, please refer to “Series Three Error Code Definitions” available on the Series Three documentation section.

How do I know what a particular Series Three PLC error code means?

A table containing descriptions of all possible errors and the actions necessary to correct them is “Series Three Error Code Definitions” available on the Series Three documentation section.