FX3U is a third-generation compact programmable logic controller (PLC) developed by Mitsubishi Electric. It represents the top tier within the FX series of PLCs. Employing a basic unit plus expansion architecture, the FX3U is fully compatible with the entire functionality of the FX2N series while significantly enhancing basic performance through the utilization of a higher-performance CPU compared to its predecessor.

Key features of the FX3U include:

Expanded I/O Capacity:

Capable of controlling up to 256 I/O points directly, with full compatibility with FX2N's I/O expansion units and modules. Through remote I/O connection, this capacity can be extended to a maximum of 384 points.
Enhanced Programming Capabilities:

Strengthened application instructions, offering functionalities such as communication with Mitsubishi inverters, CRC calculation, and generation of random numbers.
Increased software component availability, including expanded internal relays, status relays, and timers.
Improved Speed and Memory:

Executes basic instructions at a rate of just 0.065μs per instruction and application instructions at 0.642μs per instruction, significantly faster than the FX2N series.
Offers a user program memory capacity of up to 64K steps, expandable via flash cards.
Enhanced Communication:

Built-in programming port supporting high-speed communication up to 115.2Kbps, with the capability to utilize up to 3 communication ports simultaneously, including the programming port.
Addition of RS-422 standard interface and communication modules for network connectivity, alongside compatibility with USB interfaces through conversion devices.
Advanced Counting and Positioning Control:

Incorporates high-speed counting functionality, with 6 points capable of simultaneous counting at up to 100kHz, including quadruple frequency counting in two-phase operations.
Basic units feature built-in 3-axis independent positioning functions, supporting speeds of up to 100kHz, with additional positioning instructions enhancing control capabilities.
Versatile Special Adapters:

Introduction of adapters for high-speed input/output, analog input/output, and temperature input, enhancing the speed of high-speed counting and positioning control without consuming system points.
Option for installation of high-performance display modules (FX3U-7DM) for added functionality.

In essence, FX3U represents a significant advancement in industrial automation technology, offering users increased flexibility, performance, and efficiency for a wide range of applications.