Mitsubishi MELSEC FX0N Series Modules – FX0N-485ADP

Technical Dossier

Product Details And Specifications

Mitsubishi MELSEC FX0N Series Technical Notes

The Mitsubishi MELSEC FX0N series is a compact, fixed-I/O programmable logic controller platform developed by Mitsubishi Electric for deployment in space-constrained industrial automation environments. Installed across petrochemical processing units, water treatment facilities, pharmaceutical batch lines, and light manufacturing cells globally, the FX0N occupies a defined position in the MELSEC FX family between the entry-level FX0S and the more capable FX2N. Its 24 VDC input architecture, relay and transistor output variants, and RS-422/RS-485 communication support made it a standard selection for OEM machine builders throughout the 1990s and early 2000s. Units remain operational in legacy installations across chemical plants in Southeast Asia, packaging lines in Europe, and material handling systems in North America, driving sustained demand for spare parts and replacement modules.

The Evolution of FX0N Architecture

The FX0N was introduced as part of Mitsubishi Electric's second-generation compact PLC strategy, succeeding the FX0 and FX0S platforms. Its architecture centers on a fixed main unit with integrated power supply, CPU, and I/O, supplemented by a limited range of special function modules connected via the FX0N expansion bus. The CPU executes a standard MELSEC instruction set compatible with GX Developer and GX Works2 programming environments, enabling program migration from earlier FX-series hardware.

The FX0N supports up to 128 I/O points when expanded, using dedicated extension units and blocks. Communication is handled via the built-in RS-422 programming port and optional RS-485 adapters such as the FX0N-485ADP, which enables MODBUS RTU and non-protocol serial communication with HMIs, inverters, and SCADA systems. The series does not support the FX3U/FX3G-generation high-speed counters or the CC-Link field network natively, marking a clear generational boundary.

FX0N Full Catalog & Functionalities (SKU List)

CPU / Main Units

• FX0N-24MR-ES/UL: 24-point relay output main unit, 100–240 VAC power supply, 14 inputs / 10 outputs.
• FX0N-24MT-ESS/UL: 24-point transistor sink output main unit, 100–240 VAC, high-speed pulse output capable.
• FX0N-40MR-ES/UL: 40-point relay output main unit, 24 inputs / 16 outputs, expandable to 128 I/O.
• FX0N-40MT-ESS/UL: 40-point transistor sink output main unit, 100–240 VAC, suitable for stepper/servo positioning.
• FX0N-60MR-ES/UL: 60-point relay output main unit, 36 inputs / 24 outputs, maximum base I/O configuration.
• FX0N-60MT-ESS/UL: 60-point transistor sink output main unit, 36 inputs / 24 outputs.

Extension I/O Units & Blocks

• FX0N-8EX: 8-point digital input extension block, 24 VDC sink/source, DIN rail mount.
• FX0N-8EYR: 8-point relay output extension block, 2A per point, 250 VAC / 30 VDC rated.
• FX0N-8EYT: 8-point transistor sink output extension block, 0.5A per point.
• FX0N-16EX: 16-point digital input extension block, 24 VDC, compact form factor.
• FX0N-16EYR: 16-point relay output extension block, general-purpose discrete control.
• FX0N-16EYT: 16-point transistor sink output extension block, high-frequency switching.

Analog & Special Function Modules

• FX0N-3A: 2-channel analog input (0–10 VDC / 4–20 mA) + 1-channel analog output, 8-bit resolution.

Communication Adapters

• FX0N-485ADP: RS-485 communication adapter, supports MODBUS RTU master/slave and non-protocol serial communication; connects to the FX0N programming port via dedicated adapter interface; enables multi-drop network topology with up to 32 nodes; operating voltage 5 VDC supplied from main unit.
• FX0N-232ADP: RS-232C communication adapter, single-channel serial interface for HMI and barcode reader connectivity, non-protocol and MELSEC protocol support.

Power Supply & Accessories

• FX0N-65EC: Extension cable, 65 cm, connects FX0N main unit to remote I/O extension blocks.
• FX0N-30EC: Extension cable, 30 cm, short-run I/O expansion connection.
• FX0N-CNV-BC: Bus conversion module, enables connection of FX2N-series special function modules to FX0N main units.

Quality Control for the FX0N Range

FX0N modules present specific verification challenges due to their integrated bus architecture and age-related component degradation. DriveKNMS applies a structured inspection protocol to all FX0N units prior to dispatch:

• Visual inspection for PCB corrosion, relay contact wear, and capacitor bulge on power supply sections.
• Functional power-on test with voltage measurement at 5 VDC and 24 VDC internal rails.
• I/O point verification using a dedicated test fixture that cycles all input and output channels under load.
• Communication port validation for RS-422 and RS-485 adapters using loopback testing at 9600, 19200, and 38400 baud rates.
• Program read/write cycle test via GX Developer to confirm CPU memory integrity and battery-backed data retention.
• Burn-in period of minimum 24 hours under simulated load conditions before final packaging.

Units that fail any stage of this protocol are quarantined, documented, and either routed for component-level repair or classified as non-functional for parts-only disposition.