Idec Plc Fa2j Manual ((hot)) May 2026

This is a deep review and analysis of the IDEC FA2J PLC User Manual.

Although the FA2J is a legacy model (often succeeded by the FA3S, MicroSmart, and currently the SmartAxis series), it remains a staple in many maintenance environments. Because it is older technology, the manual itself becomes a critical tool for troubleshooting existing machinery.

Here is a detailed breakdown of the manual’s structure, usability, technical depth, and limitations.

The "Special Internal Relays" (M8120 - M8199)

The back of the FA2J programming manual contains a cheat sheet of special relays. For example:

  • M8120: "Initial Pulse" (ON for one scan at power-up).
  • M8121: "Always ON" contact.
  • M8122: "Always OFF" contact.
  • M8123: 0.1 second clock pulse.

Without the manual, you would never know these exist.

Decoding the FA2J Hardware Manual (Installation & Wiring)

If you open the IDEC PLC FA2J Manual to the hardware section, pay attention to three critical areas:

What the FA2J is

  • Compact, entry-level programmable logic controller (PLC) from IDEC.
  • Used for small automation tasks: motor control, timers/counters, simple sequencing, and I/O monitoring.
  • Typically features a modest number of built-in inputs/outputs and supports ladder logic programming.

Example search terms

  • “IDEC FA2J user manual PDF”
  • “FA2J programming manual ladder logic”
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If you want, I can draft a full blog post (600–900 words) targeted to technicians, with step-by-step setup instructions and example ladder snippets; tell me the audience (technician, engineer, hobbyist) and desired length. idec plc fa2j manual

IDEC FA2J Series PLC Specification Report (also known as the FA-2 Junior

) is a modular, flat-pack programmable logic controller designed for industrial automation. It is a legacy system often compatible with older software and hardware standards. 5.imimg.com 1. System Overview Design Architecture

: Flat-pack modular design, allowing for flexible configuration of input and output modules. Processing Speed : Approximately Programming Languages : Supports standard Ladder Logic Boolean instructions 2. Technical Specifications Specification Details I/O Capacity total inputs and outputs. Memory Capacity Options for Input Modules Available in both configurations. Output Modules Choices between Transistor Internal Features

Includes internal relays, counters, timers, and bidirectional shift registers. 3. Software and Connectivity Programming Software : Modern programming can be performed using IDEC WindLDR software , which supports the FA-2J series. Computer Interfacing

: Supports computer linking to personal computers (originally IBM 5150/5160 compatible) for program management and printing. Third-Party Integration

: The series can interface with SCADAPack E RTUs using specific serial port drivers. device.report 4. Critical Support Documents Official User Manual : Reference number Analog I/O Support 8-Bit Analog I/O Manual ( 12-Bit Analog Input Manual ( Cross-Reference Square D SFW50 PLC This is a deep review and analysis of

is physically and functionally similar to the FA2J and its manual can often serve as a technical reference. Galco Industrial Electronics current replacement parts for this legacy system? IDEC FA2J PLC Specifications Guide | PDF - Scribd

One interesting feature detailed in the IDEC FA2J PLC manual is its replaceable relay system within a flat-pack modular design. This design allows you to maintain high reliability in harsh industrial environments without needing to replace entire modules when a single relay reaches its end-of-life. Key Technical Features

Modular Architecture: The FA2J uses a low-profile, flat-pack design specifically engineered for shallow panels where space is at a premium.

High-Speed Processing: It offers a processing speed of 6ms per 1K basic instructions, which was a significant improvement (roughly 5x faster) over the earlier FA1J series.

Scalable I/O: The system can handle up to 128 inputs and 128 outputs, totaling 256 points, providing substantial flexibility for expanding automation tasks.

Robust Diagnostic Suite: The manual highlights built-in self-diagnostics, including a watchdog timer (WDT), communication error detection, and CRC checks in user programs to ensure operational stability. The "Special Internal Relays" (M8120 - M8199) The

Memory Versatility: It supports 1K or 4K CMOS-RAM (with battery backup) and 4K EEPROM memory packs, allowing for flexible program storage options. Performance Specifications Specification Available Instructions 15 basic, 57 advanced instructions Timer Capabilities 80 points of 10ms subtracting timers (0 to 999.9s) Counter Capacity 45 adding counters (0 to 9,999) and 2 reversible counters Power Failure Protection

Protects internal relays, shift registers, and data registers

While the FA2J is now a discontinued product, it remains a reliable solution for many existing automation systems due to its durability and easy-to-integrate modular setup. IDEC FA2J PLC Specifications Guide | PDF - Scribd

Otherwise, absolutely not. Recommendations:

  • For identical footprint/relay replacement: Use IDEC SmartRelay (FL1E) – similar size, modern software, same I/O count.
  • For upgrade path with existing IDEC: Move to IDEC MicroSmart (FC6A) – retains ladder logic feel but has Ethernet, SD card, and free programming software (WindLDR or Automation Organizer).
  • For lowest cost new: AutomationDirect CLICK PLUS – $69 CPU, free software, USB programming.

2. Input Wiring (Sink/Source Configuration)

The FA2J manual contains a famous diagram showing how to wire switches. You must configure the common terminal (C) based on your sensor type:

  • Sink Input (NPN): Common terminal connects to +24V.
  • Source Input (PNP): Common terminal connects to 0V.
  • Warning from the manual: Mixing these up without an opto-isolator will short the power supply.

1. Overview & Positioning

The IDEC FA-2J is a micro/nano PLC from the 1990s–early 2000s era. It is the direct predecessor to the popular MicroSmart series. Its primary claim to fame is being one of the smallest PLCs at its time with a built-in power supply, CPU, I/O, and programmer port in a housing slightly larger than a deck of cards.

Target Audience (Legacy): Machine builders needing simple relay replacement, standalone sequence control, or OEM cost-sensitive applications.
Current Use Case: Only for maintaining existing machinery. Do not use for new designs (discontinued; parts scarce; software obsolete).