Mitsubishi MELSEC-F Series Modules: FX3U-32M SAC-DE03C2/I, FX2N-16EYR-ES/UL, FX2N-8AD, 853-030675-001, 000-1106-100

Technical Dossier

Product Details And Specifications

Mitsubishi MELSEC-F Series: Comprehensive Module Range and Technical Overview

The Mitsubishi MELSEC-F Series — encompassing the FX1S, FX1N, FX2N, FX3U, FX3G, and FX3GE sub-families — represents one of the most widely deployed compact PLC platforms in global heavy industry. Installed across petrochemical complexes, nuclear auxiliary systems, refinery process lines, automotive assembly plants, and water treatment facilities, the MELSEC-F architecture has maintained a continuous production lineage from the early 1980s through to the present FX5U generation. Its modular I/O expansion architecture, deterministic scan-cycle performance, and broad third-party communication compatibility have made it the reference platform for compact automation in Asia-Pacific, EMEA, and North American markets. The FX3U sub-series, in particular, achieved dominant market penetration in the 2005–2020 period and remains the most common legacy platform requiring spare parts support globally.

The Evolution of MELSEC-F Architecture

The MELSEC-F Series originated with the F1/F2 generation in the early 1980s, offering fixed I/O configurations with relay and transistor output options. The FX0/FX0N generation introduced compact form factors with limited expansion. The FX1S and FX1N lines (mid-1990s) added onboard analog capability and high-speed counter inputs. The FX2N (released 1998) marked the first full-featured expansion bus architecture, supporting up to 256 I/O points via FX2N-series extension modules and a broad library of special function modules including analog, temperature, positioning, and communication adapters.

The FX3U (released 2004) introduced a 32-bit RISC CPU, USB programming port, built-in high-speed I/O (100 kHz), and compatibility with the FX3U-ENET Ethernet adapter and CC-Link IE Field Basic. The FX3G and FX3GE variants offered cost-optimized alternatives with integrated Ethernet (FX3GE). The current generation FX5U (released 2016) features a built-in Ethernet port, SD card slot, and iQ Works integration, but is not backward-compatible with FX3U expansion modules — a critical consideration for system integrators managing mixed-generation installations. Sites running FX2N or FX3U hardware must source original-series modules; cross-generation substitution is not supported at the backplane level.

MELSEC-F Series Full Catalog & Functionalities (SKU List)

Main Units / CPU Modules

• FX3U-32M SAC-DE03C2/I: FX3U 32-point main unit, AC power supply, sink/source mixed I/O, with DE03C2/I connector set
• FX3U-16M: FX3U 16-point main unit, compact form, AC power, relay output
• FX3U-48M: FX3U 48-point main unit, AC power, transistor sink output
• FX3U-64M: FX3U 64-point main unit, high-density I/O, relay or transistor output
• FX3U-128M: FX3U 128-point main unit, maximum onboard I/O configuration
• FX3G-24M: FX3G 24-point main unit, cost-optimized, relay output, RS-422 port
• FX3GE-24M: FX3GE 24-point main unit with integrated Ethernet port

Digital Output Modules

• FX2N-16EYR-ES/UL: FX2N 16-point relay output expansion module, UL/cUL listed, 2A per point, 250VAC/30VDC rated
• FX2N-16EYT: FX2N 16-point transistor sink output expansion module, 0.5A per point
• FX2N-32EYR: FX2N 32-point relay output expansion module
• FX2N-32EYT: FX2N 32-point transistor sink output expansion module

Analog Input Modules

• FX2N-8AD: FX2N 8-channel analog input module, 12-bit resolution, voltage/current selectable per channel, ±10V / 4–20mA
• FX3U-4AD: FX3U 4-channel analog input, 16-bit resolution, high-accuracy voltage/current input
• FX3U-8AD: FX3U 8-channel analog input, 16-bit resolution, thermocouple/voltage/current multi-mode
• FX2N-4AD: FX2N 4-channel analog input, 12-bit, voltage/current selectable

Analog Output Modules

• FX3U-4DA: FX3U 4-channel analog output, 12-bit, voltage/current output
• FX2N-4DA: FX2N 4-channel analog output, 12-bit resolution

Communication & Network Adapters

• FX3U-ENET: Ethernet communication module for FX3U, 100BASE-TX, SLMP/MC protocol support
• FX3U-232ADP-MB: RS-232C communication adapter with Modbus RTU master/slave support
• FX3U-485ADP-MB: RS-485 communication adapter, Modbus RTU, up to 16 nodes
• FX2N-232IF: FX2N RS-232C interface module, full-duplex serial communication

Positioning Modules

• FX3U-20SSC-H: FX3U SSCNET III/H high-speed positioning module, 2-axis servo control
• FX2N-10PG: FX2N pulse output positioning module, 1-axis, 100 kHz max output

Accessories / Connector Sets (Current Product SKUs)

• 853-030675-001: Assembly/connector reference part number associated with FX3U main unit installation kit
• 000-1106-100: Supplementary component reference, cross-referenced to FX-series wiring accessory
• SAC-DE03C2/I V1.0A: Connector assembly version 1.0A for FX3U-32M SAC variant I/O terminal block

Sourcing Hard-to-Find & Obsolete MELSEC-F Series Parts

The FX2N sub-series reached end-of-production in 2013 and entered full end-of-life status in 2020. Mitsubishi Electric no longer manufactures FX2N main units or expansion modules through standard distribution channels. The FX3U series entered a managed lifecycle phase in 2022 with the FX5U designated as the strategic successor. However, the absence of backplane compatibility between FX3U and FX5U means that installed FX3U and FX2N systems cannot be upgraded incrementally — full panel redesign is required for migration.

Quality Control for the MELSEC-F Series Range

MELSEC-F modules use a proprietary FX-BUS backplane communication protocol operating at 2.5 Mbps between the main unit and expansion modules. Failure modes specific to this architecture include backplane connector oxidation (common in high-humidity environments), EEPROM parameter corruption on analog modules after power cycling, and relay contact wear on high-cycle EYR output modules.

DriveKNMS applies the following test protocol to all MELSEC-F units: (1) Visual inspection of PCB, relay contacts, and terminal blocks. (2) Power-on functional test with GX Works2/GX Developer to verify CPU scan cycle, I/O map, and error register status. (3) For analog modules (FX2N-8AD, FX3U-4AD, etc.): channel-by-channel signal injection test across full input range with calibration verification. (4) For relay output modules (FX2N-16EYR-ES/UL, FX2N-32EYR): contact resistance measurement and rated-load switching endurance test. (5) Communication adapter loopback test for RS-232C/RS-485/Ethernet modules. All units are dispatched with a test report.