The FX3U-32MT/ES-A is Mitsubishi Electric’s 32-point transistor output compact programmable controller from the MELSEC FX3U series — providing 16 digital inputs and 16 transistor sink outputs in a single base unit with built-in RS-422 and RS-485 communication ports, built-in high-speed counter and pulse output capability, and the FX3U platform’s extensive special function module ecosystem for expanding to servo positioning, analog I/O, and communications — the mid-range I/O count base unit in the FX3U series with transistor output for high-cycle switching and pulse output positioning applications. The FX3U-32MT/ES-A is available through Atlantech Drives — quote within 24-48 hours, worldwide express shipping, 12-month warranty.
What Is the FX3U-32MT/ES-A?
The FX3U-32MT/ES-A is a MELSEC FX3U series compact PLC base unit providing 16 digital inputs (24 VDC sink) and 16 transistor sink output points (24 VDC, 0.5 A per point) in a 32-point total I/O configuration. The «/ES-A» suffix identifies the 100–240 VAC wide-range power supply with sink output transistors (NPN) — the «ES» indicating European and world-wide power supply compatibility, and «A» denoting the additional RS-485 port built into this variant alongside the standard RS-422 port, providing dual serial communication capability without requiring an option board. The FX3U-32MT/ES-A includes 6 built-in high-speed counter inputs (up to 100 kHz per channel, with AB-phase encoder input capability) for encoder feedback in positioning and speed measurement applications, and 3 built-in pulse output channels (up to 100 kHz open-collector for Y0, Y1, Y2) for controlling step motor drivers or MR-J4-A servo amplifier pulse train inputs. The dual serial communication ports (RS-422 for GOT HMI and GX Works2 programming, RS-485 for Modbus RTU device communication) enable simultaneous HMI connection and PLC-to-device serial network without option boards — an important differentiator of the «/ES-A» variant versus the standard «/ES» model which includes only the RS-422 port.
Key Technical Specifications
- Model: FX3U-32MT/ES-A
- Total I/O Points: 32 (16 inputs + 16 transistor sink outputs)
- Input Type: 24 VDC sink (NPN-compatible)
- Output Type: Transistor sink (NPN, 24 VDC, 0.5 A per point)
- Power Supply: 100–240 VAC, 50/60 Hz
- Program Memory: 64,000 steps
- Built-in Communication: RS-422 (programming/HMI) + RS-485 (Modbus/device)
- Built-in High-Speed Counters: 6 channels (up to 100 kHz single-phase, 50 kHz AB-phase)
- Built-in Pulse Outputs: 3 axes (Y0, Y1, Y2 — up to 100 kHz open-collector)
- Extension Modules: Up to 8 extension I/O modules
- Special Function Modules: Up to 8 (FX3U/FX2N series)
- Option Boards: Up to 2 (FX3U-□BD series communication option boards)
- Operating Temperature: 0°C to 55°C
- Dimensions (W × H × D): 90 mm × 90 mm × 87 mm
- Weight: Approx. 0.50 kg
Architecture & Design Overview
The FX3U-32MT/ES-A implements the FX3U series controller architecture — the highest-performance compact PLC in the MELSEC FX3 family, with 0.065 µs per basic instruction execution time versus the FX3G’s 0.21 µs and the FX2N’s 0.08 µs. The transistor sink outputs use NPN open-collector transistors providing 0.5 A per point at 24 VDC — the transistor output’s unlimited switching life (versus the FX3U-32MR relay output’s 200,000-operation relay life) and 0.2 ms response time (versus relay’s 10 ms) are critical for the built-in pulse output positioning function, as the pulse output’s 100 kHz pulse frequency requires output switching at 200,000 transitions per second — well beyond relay contact switching capability. The FX3U’s built-in pulse output function uses the DRVI (incremental position drive) and DRVA (absolute position drive) special function instructions to generate pulse trains for servo or step motor positioning from the FX3U ladder program, with the positioning parameters (target position, speed, acceleration time) specified as operands in the instruction. For multi-axis coordinated positioning from the FX3U-32MT/ES-A without a separate positioning module, the simultaneous independent positioning of all 3 pulse output channels (Y0, Y1, Y2) from separate DRVI/DRVA instructions enables 3-axis independent simultaneous positioning for Cartesian robot and gantry applications within the FX3U platform’s 64,000-step program memory. The built-in RS-485 port in the FX3U-32MT/ES-A communicates using Mitsubishi’s RS-485 communication instructions (RS instruction for free protocol, or IVDR/IVRD for inverter multi-drop control) enabling communication with multiple FR-series inverter drives for coordinated speed control from the FX3U ladder without a separate communications module.
Frequently Asked Questions
Q: What is the difference between the FX3U-32MT/ES-A and the FX3U-32MT/ES without the «-A» suffix?
A: The FX3U-32MT/ES-A includes a built-in RS-485 port in addition to the standard RS-422 port, providing dual serial communication capability. The standard FX3U-32MT/ES includes only the RS-422 port — a second serial port (RS-485, RS-232C) requires an FX3U-□BD option board to be fitted. The «/ES-A» variant is the correct selection when RS-485 device communication (Modbus RTU, inverter multi-drop) and RS-422 HMI communication are both required simultaneously without consuming an option board slot for the RS-485 port.
Q: Can the FX3U-32MT/ES-A’s built-in pulse outputs control MR-J4-A MELSERVO servo amplifiers for absolute positioning?
A: Yes. The FX3U-32MT/ES-A’s 100 kHz open-collector pulse outputs connect directly to MR-J4-A servo amplifiers’ open-collector pulse input for positioning control using the DRVA (absolute position drive) or DRVI (incremental position drive) instructions. For absolute position detection without homing at power-up, configure the MR-J4-A amplifier’s absolute position detection parameters (parameter PC30) and use the DSZR (zero return) instruction in the FX3U program to read the servo motor’s absolute encoder position at startup — the FX3U-32MT/ES-A supports absolute position detection with MR-J4-A amplifiers equipped with 22-bit absolute encoders through the built-in high-speed counter input receiving the servo amplifier’s encoder output signal.
Q: What is the maximum number of special function modules that can be connected to the FX3U-32MT/ES-A?
A: The FX3U-32MT/ES-A supports up to 8 special function modules (FX3U-4AD analog input, FX3U-4DA analog output, FX3U-20SSC-H SSCNET III/H servo, FX3U-ENET-ADP Ethernet, and others) in the right-side extension chain, in addition to up to 8 extension I/O modules. The special function module count includes both FX3U-series modules and compatible FX2N-series special function modules — the total combination of special function modules and extension I/O modules must not exceed 8 each. For the FX3U-20SSC-H SSCNET III/H servo adapter (providing 2 MR-J4-B SSCNET III/H servo axes), count it as one special function module, enabling simultaneous SSCNET III/H servo control alongside other FX3U-32MT/ES-A special functions.
Do you need more references from this brand? Explore our full catalog of Mitsubishi here: https://atlantechdrives.com/manufacturers/mitsubishi/
