available on the FA2J—Leo found a glitch in a high-speed counter. With a few clicks on the handheld programmer and a quick swap of a replaceable relay , the FA2J hummed back to life.

A: The FA2J-CPU models use a lithium battery (CR2032) to retain the data registers (D) and internal relays (M) during power loss. The manual specifies changing this battery every 5 years. Location: Under the front access cover.

The manual generally follows the standard progression of PLC documentation from that era.

The IDEC FA2J series (often referred to as the FA-2 Junior) is a legacy flat-pack modular programmable logic controller known for its reliability in industrial and marine automation. Although the series has been discontinued by the manufacturer, it remains widely used in existing control panels due to its high-density design and flexible expansion capabilities.

: This Product Catalog PDF from Galco provides a detailed overview of the FA2J series, including its modular design, memory capacity (

The FA2J manual provides detailed information on programming, operating, and maintaining the PLC. The manual covers the hardware and software configuration, programming instructions, and troubleshooting guidelines for the FA2J PLC.