FX2N-8ER-ES/UL is an 8-point relay output extension module for Mitsubishi Electric’s MELSEC FX2N series programmable logic controllers, providing 4 DC inputs and 4 relay outputs to expand the I/O capacity of an existing FX2N base unit. The ES/UL suffix confirms compliance with both European (CE) and North American (UL/cUL) safety standards, making this module suitable for machine installations in both markets without requiring additional certification. Atlantech Drives holds stock of the FX2N-8ER-ES/UL. Contact us for fast worldwide delivery and competitive pricing.
What Is the FX2N-8ER-ES/UL?
The FX2N-8ER-ES/UL is a compact right-side extension module that connects directly to the FX2N main base unit or to other FX2N extension modules via the dedicated expansion bus connector. The «8E» denotes 8 extension I/O points, «R» identifies the output type as relay contact, and «ES/UL» confirms dual market certification. Each relay output is rated at 2 A per point for resistive loads, making it suitable for direct switching of solenoid valves, contactors, indicator lamps, and small motor starters without an intermediate relay layer. The 4 inputs are 24 V DC sink type, compatible with standard PNP proximity sensors and pushbutton circuits used across the FX2N I/O range. The module draws its logic power from the FX2N expansion bus and requires no separate external power supply, simplifying installation in retrofit and repair scenarios where cabinet space and wiring changes must be minimised.
Key Technical Specifications
- Total I/O Points: 8 (4 inputs / 4 relay outputs)
- Input Type: 24 V DC sink (compatible with FX2N standard input specs)
- Input Impedance: 3.9 kΩ
- Output Type: Relay contact (Form A, normally open)
- Output Rated Current: 2 A per point (resistive load, 250 V AC / 30 V DC)
- Output Common Configuration: 1 common for all 4 output points
- Relay Electrical Life: 200,000 operations at rated load
- Relay Mechanical Life: 20,000,000 operations
- Power Consumption: 5 V DC, 30 mA (from FX2N expansion bus)
- Certification: CE (EN 61131-2), UL 508, cUL
- Operating Temperature: 0 °C to 55 °C
- Dimensions (W × H × D): 55 × 90 × 87 mm
- Weight: Approx. 200 g
Typical Industrial Applications
The FX2N-8ER-ES/UL is most commonly encountered as a maintenance replacement part in installed FX2N-based machinery that requires additional discrete I/O without a full controller replacement. Typical applications include textile and packaging machines where the original I/O count proved insufficient for retrofitted safety interlocks or additional sensor inputs added during a machine upgrade cycle. In food processing equipment, the relay output type is preferred over transistor outputs for switching 230 V AC solenoid valves directly, as relay contacts provide galvanic isolation between the PLC logic circuit and the load circuit — an important consideration in washdown environments where ground potential differences between equipment can cause transistor output latch-up. In building automation legacy systems, FX2N-based controllers managing HVAC zone control and damper actuators are routinely extended with FX2N-8ER modules to accommodate additional zones added during building refurbishment, deferring a full controller replacement until the next planned maintenance window.
Maintenance Tips
Relay output modules are the highest-wear component in any PLC I/O system due to the mechanical nature of the contact switching. For the FX2N-8ER-ES/UL, track relay operation counts per output point where possible using the PLC’s internal counter registers — assign one counter per output coil address and log cumulative switch counts to a data register for maintenance reporting. The manufacturer’s rated electrical life of 200,000 operations at full rated load drops significantly with inductive loads: a solenoid valve without a suppression diode or RC snubber will reduce relay contact life to as few as 20,000–50,000 operations due to arc erosion. Fit suppression components at the load, not at the relay output terminal. If intermittent output faults occur on a single point while adjacent points remain functional, suspect contact welding or carbon buildup on that relay — replace the module rather than attempting contact cleaning, as abrasive cleaning compounds contaminate adjacent contacts. When storing FX2N-8ER-ES/UL units as spares, exercise each relay output once per 6 months by briefly energising the output coil — static storage causes oxide buildup on silver-alloy contacts that increases contact resistance on first operation after long idle periods.
Frequently Asked Questions
Q: Is the FX2N-8ER-ES/UL compatible with the FX2NC or FX3U base units?
A: The FX2N-8ER-ES/UL is mechanically and electrically compatible with the FX2N series only. It is not directly compatible with the FX2NC (which uses a different compact connector format) or the FX3U (which has a different expansion bus protocol). FX3U systems require FX3U-series extension modules. For FX2NC systems, Mitsubishi offers the FX2NC-8ER equivalent with the appropriate connector format.
Q: How many FX2N-8ER-ES/UL modules can be connected to a single FX2N base unit?
A: The FX2N system supports a maximum of 8 extension modules on the right-side expansion bus, subject to the total I/O point limit of 256 points (including the base unit). The combined current draw of all extension modules must not exceed the expansion bus power supply capacity of the FX2N base unit — verify the power budget in the FX2N Hardware Manual (JY992D66301) before adding multiple extension modules to an existing system.
Q: Can the relay outputs on the FX2N-8ER-ES/UL switch AC and DC loads on different points simultaneously?
A: Yes. Because all 4 relay outputs share a single common terminal, all output points in that common group must use the same load voltage. If mixed AC and DC switching is required across the 4 output points, an external interposing relay layer is necessary to isolate the different load voltages from the shared common — the FX2N-8ER-ES/UL output common cannot be split internally.
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