The FX3G-40MT/ESS is Mitsubishi Electric’s 40-point transistor output compact programmable controller from the MELSEC FX3G series — providing 24 digital inputs and 16 transistor (sink) outputs in a single base unit with built-in RS-422 programming port and USB mini-B port, designed for cost-effective standalone machine control requiring transistor output switching speed, high-speed counter capability, and the FX3G platform’s straightforward GX Works2 programming environment. Atlantech Drives holds stock of the FX3G-40MT/ESS. Contact us for fast worldwide delivery and competitive pricing.
What Is the FX3G-40MT/ESS?
The FX3G-40MT/ESS is a MELSEC FX3G series compact PLC base unit providing 24 digital inputs (24 VDC sink) and 16 transistor sink output points (24 VDC, 0.5 A per point) in a 40-point total I/O configuration. The «40MT» designates 40 total I/O points with transistor output type; «/ESS» identifies the 200–240 VAC power supply with sink output transistors (NPN — the output transistor pulls the output terminal to 0 VDC when ON, sourcing current from the load’s positive supply). The transistor output type provides significant advantages over relay outputs in the FX3G-40MT/ESS — unlimited electrical switching life, faster output response time (approximately 0.2 ms versus 10 ms for relay), and compatibility with the FX3G’s built-in high-speed pulse output function for step motor and servo axis positioning. The FX3G-40MT/ESS includes 6 built-in high-speed counter inputs (up to 60 kHz per channel) for encoder feedback in positioning applications, and 2 built-in pulse output channels (up to 100 kHz) for step motor or MR-J4-A servo amplifier positioning via open-collector pulse train. The built-in USB mini-B port enables direct GX Works2 programming connection from any modern PC without requiring a USB-to-RS-422 adapter, providing a convenient alternative to the built-in RS-422 port for programming and online monitoring access.
Key Technical Specifications
- Model: FX3G-40MT/ESS
- Total I/O Points: 40 (24 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: 32,000 steps
- Built-in Communication: RS-422 (programming/HMI), USB mini-B (programming)
- Built-in High-Speed Counters: 6 channels (up to 60 kHz single-phase, 30 kHz AB-phase)
- Built-in Pulse Outputs: 2 axes (up to 100 kHz open-collector)
- Extension Modules: Up to 8 modules (FX3G/FX3U extension I/O and special function modules)
- Special Function Modules: Up to 4 (FX3U special function modules via FX3U-CNV-BD adapter)
- Operating Temperature: 0°C to 55°C
- Dimensions (W × H × D): 130 mm × 90 mm × 75 mm
- Weight: Approx. 0.55 kg
Architecture & Design Overview
The FX3G-40MT/ESS implements the FX3G series controller architecture — a cost-optimised compact PLC platform positioned between the entry-level FX3S and the higher-capability FX3U in the MELSEC FX3 product family. The FX3G CPU processes the ladder diagram (or structured text/function block in GX Works2) at a basic instruction execution time of 0.21 µs per step — approximately 3× faster than the FX2N generation and adequate for the majority of machine control applications. The transistor sink outputs use NPN open-collector transistors switching the output terminal between 24 VDC (load common, output OFF) and 0 VDC (output ON, transistor conducting) — the 0.5 A per point continuous rating covers standard solenoid valve coils (typically 0.1–0.3 A), step motor driver step/direction inputs (typically <10 mA), and DC relay coils (typically 0.05–0.1 A), while exceeding the 0.5 A limit requires an external relay. The FX3G-40MT/ESS's built-in pulse output function uses two dedicated high-speed output channels (Y0 and Y3 in the 40-point model) capable of generating pulse trains at up to 100 kHz for open-collector step motor driver or MR-J4-A servo amplifier pulse train input — the DDRVI (relative position drive) and DDRVA (absolute position drive) special function instructions control the pulse output from the FX3G ladder program, providing basic single-axis positioning without a separate positioning module. The FX3G program memory (32,000 steps) is approximately 4× the FX2N's capacity (8,000 steps standard), accommodating more complex machine programs with structured subroutines and data handling routines within the FX3G's instruction set.
Frequently Asked Questions
Q: Can the FX3G-40MT/ESS be programmed with GX Works3, or is GX Works2 required?
A: The FX3G-40MT/ESS requires GX Works2 for programming — GX Works3 supports only the MELSEC iQ-F (FX5U, FX5UC) and iQ-R series, not the FX3G. GX Works2 provides full FX3G programming capability including ladder diagram, function block, and structured text (SFC) programming, as well as online monitoring, device monitoring, and parameter configuration for the FX3G platform.
Q: What is the maximum total I/O count achievable with the FX3G-40MT/ESS including extension modules?
A: The FX3G-40MT/ESS supports up to 8 extension modules, with a maximum total I/O count of 256 points (built-in 40 points + up to 216 extension points). FX3G extension modules (FX3G-16EX, FX3G-16EYT, and others) and FX3U extension modules (via FX3U-CNV-BD conversion adapter) can both be used in the FX3G extension chain, providing access to the wider FX3U special function module range including communication modules and special analog/high-speed modules.
Q: Does the FX3G-40MT/ESS support absolute position detection with servo amplifiers for homing-free operation?
A: The FX3G-40MT/ESS’s built-in pulse output function supports absolute position detection with MR-J4-A servo amplifiers equipped with 22-bit absolute encoders — the DSZR (zero return) instruction combined with the servo amplifier’s absolute encoder data output enables the FX3G to read the motor’s absolute position at power-up without a homing cycle. Configure the servo amplifier’s absolute position detection parameters in MR Configurator2 and set the FX3G’s zero return parameters accordingly to enable homing-free absolute positioning from the built-in pulse output axes.
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