The FX3U-80MR/ES-A is Mitsubishi Electric’s 80-point relay output base unit for the MELSEC FX3U compact PLC series — the largest relay output base unit in the FX3U range — providing 40 digital inputs and 40 relay contact outputs in a self-contained AC-powered controller for complex standalone machine control applications requiring a high I/O count with relay output versatility, without the size and cost of a modular MELSEC-Q or MELSEC iQ-R system. As the maximum I/O density relay output model in the FX3U family, the FX3U-80MR/ES-A is specified for machines where 32-point base units with I/O expansion prove bulkier or more expensive than a single 80-point base unit, and where relay output capability for direct AC load switching is required across a large number of output points. Atlantech Drives holds stock of the FX3U-80MR/ES-A. Contact us for fast worldwide delivery and competitive pricing.
What Is the FX3U-80MR/ES-A?
The FX3U-80MR/ES-A is a MELSEC FX3U series compact PLC base unit providing 40 input points (X0–X47, octal numbering) and 40 relay contact output points (Y0–Y47), in a widened housing that accommodates the additional I/O terminal capacity while maintaining the standard FX3U mounting height and depth for DIN rail installation. The relay outputs are organised in five common groups of 8 points each, with independent common terminals per group — enabling different output groups to control loads at different voltages simultaneously across the five zones. The FX3U CPU in the 80MR model is identical to all other FX3U base units: 0.065 µs per basic instruction, 64,000-step program memory, 6 built-in high-speed counter inputs, and 3 pulse output points (Y0, Y1: 100 kHz; Y2: 10 kHz). The high-speed pulse output points are available on the FX3U-80MR/ES-A despite its relay output designation — Y0, Y1, and Y2 are driven by transistor output circuits internal to the relay output model specifically to support pulse generation, while the remaining 37 output points (Y3–Y47) use standard relay contacts.
Key Technical Specifications
- Model: FX3U-80MR/ES-A
- Total I/O Points: 80 (40 inputs + 40 outputs)
- Input Type: 24 VDC sink (X0–X47)
- Output Type: Relay contact (Y3–Y47), 2 A per point, 240 VAC / 30 VDC; Y0/Y1 transistor (100 kHz pulse); Y2 transistor (10 kHz pulse)
- Output Common Groups: 5 groups of 8 points (independent commons per group)
- Power Supply: 100–240 VAC, 50/60 Hz
- Program Memory: 64,000 steps
- Execution Speed: 0.065 µs per LD instruction
- Built-in High-Speed Counters: 6 inputs (100 kHz)
- Communication: RS-422 (built-in)
- Real-Time Clock: Built-in
- Battery Backup: Yes
- Expansion: Up to 8 extension units, up to 4 special adapter modules
- Operating Temperature: 0°C to 55°C
- Dimensions (W × H × D): 220 mm × 90 mm × 87 mm
- Weight: Approx. 1.25 kg
Series Comparison & Selection Guide
The FX3U base unit range spans four relay output I/O counts: 16 points (FX3U-16MR/ES-A), 32 points (FX3U-32MR/ES-A), 48 points (FX3U-48MR/ES-A), and 80 points (FX3U-80MR/ES-A). The FX3U-80MR/ES-A is the correct specification when 40 or more relay outputs are required in a standalone compact PLC format without I/O expansion modules. When evaluating whether to specify the FX3U-80MR/ES-A or a smaller base unit with relay output expansion modules (FX3U-16EYR), the FX3U-80MR/ES-A is typically more economical and compact for configurations requiring 40 outputs than a 32-point base unit with three 16-point relay expansion units — the single large base unit avoids the cumulative cost and DIN rail space of multiple extension connectors and units. For applications requiring more than 80 I/O points, the FX3U-80MR/ES-A with up to 8 extension units can reach a maximum of 256 total I/O, covering the majority of compact machine control requirements. When the required I/O exceeds 256 points or when more than 4 special function adapter modules are needed, migrating to the MELSEC-Q or MELSEC iQ-F (FX5U) platform is recommended — the FX5U-80MR/ES is the direct successor offering built-in Ethernet, larger program memory (128,000 steps), and SD card data logging as standard.
Installation Advice
The FX3U-80MR/ES-A’s five independent output common groups provide significant wiring flexibility — plan the common group assignments during panel design to minimise inter-group wiring complexity. Assign all outputs controlling loads at the same voltage to the same common group where possible — for example, assign one common group exclusively to 230 VAC contactor coils, another to 24 VDC solenoid valves, and a third to 24 VDC indicator lamps — this avoids accidental cross-connection of different voltage levels within a common group and simplifies fault isolation during maintenance. The FX3U-80MR/ES-A’s wider housing (220 mm) requires more DIN rail space than the 32-point model (150 mm) — verify the available panel DIN rail length and adjacent module clearance before specifying, as some compact machine panels designed around FX3U-32MR/ES-A dimensions cannot accommodate the wider 80MR model without panel modifications. For applications in environments with significant vibration, use cable ferrules on all output wiring connections at the FX3U-80MR/ES-A terminal block — the higher number of terminals increases the total panel wiring time, and loose connections from vibration-induced terminal loosening are proportionally more likely with 80 output terminals than with 16. Mount the FX3U-80MR/ES-A with adequate vertical clearance above and below the unit for convection cooling — the higher power dissipation of the 80-point model compared to smaller base units requires unobstructed airflow through the ventilation slots on the top and bottom of the housing.
Frequently Asked Questions
Q: Does the FX3U-80MR/ES-A support simultaneous pulse output on Y0 and Y1 while the relay outputs are also actively switching?
A: Yes. The pulse output function on Y0 and Y1 uses dedicated transistor output circuits that operate completely independently of the relay output circuits — the relay outputs switching on Y3–Y47 do not affect Y0 and Y1 pulse generation. Both functions operate simultaneously without interference, enabling the FX3U-80MR/ES-A to simultaneously control relay-switched AC loads and generate high-speed positioning pulses for stepper or servo drives from the same base unit.
Q: Can the FX3U-80MR/ES-A’s relay output common groups be used at different AC voltages simultaneously?
A: Yes. Each of the five common groups has an independent common terminal — connecting different groups to different AC voltage levels (for example, 110 VAC on one group and 230 VAC on another) is fully supported, as there is no internal connection between common groups. Ensure clear circuit documentation identifying which voltage level each common group is connected to, and use appropriately rated fusing for each common group circuit to prevent cross-voltage hazards during maintenance.
Q: Is the FX3U-80MR/ES-A suitable for use in food industry applications where IP65 enclosure is required?
A: The FX3U-80MR/ES-A itself is rated IP20 (open wiring terminals, not splash-proof). For food industry applications requiring IP65 or IP67 protection, the FX3U-80MR/ES-A must be installed inside an IP65-rated sealed electrical enclosure. The enclosure must provide adequate thermal management — calculate the heat dissipation of the fully loaded FX3U-80MR/ES-A and install a panel air conditioner or heat exchanger if the enclosure internal temperature would exceed 55°C under worst-case ambient conditions and full output loading.
Do you need more references from this brand? Explore our full catalog of Mitsubishi here: https://atlantechdrives.com/manufacturers/mitsubishi/
