Wiring diagram of Mitsubishi PLC and rotary encoder - News - Global IC Trade Starts Here.

A rotary encoder is a photoelectric device that converts angular displacement into digital signals, typically in the form of high-speed pulse outputs. These pulse signals can be directly connected to a PLC (Programmable Logic Controller), where they are processed by the PLC’s high-speed counter. The measured data can then be displayed on an OMRON touch screen for real-time monitoring and control.

Rotary encoders come in different types, with varying numbers of output phases. Some models provide three-phase signals—A, B, and Z—while others only offer two phases: A and B. The simplest configuration involves just phase A, which is often used for basic position detection.

The diagram above shows the wiring setup between a two-phase rotary encoder and the FX2N series PLC. This example illustrates how the encoder connects to the PLC for accurate angular measurement.

The encoder typically has four wires: two for the pulse outputs (A and B), one for the common (COM) terminal, and one for the power supply. Depending on the application, the encoder can be powered externally or directly from the PLC’s DC24V power supply.

When connecting the power supply, make sure to connect the negative (-) terminal to the encoder’s COM port and the positive (+) terminal to the encoder’s power input. The COM terminal of the encoder should also be connected to the PLC’s corresponding input terminal.

The A and B pulse signals are connected directly to the PLC’s input terminals. It's important to consider the PLC’s input response time when making these connections. Some encoders may include a shielded wire, which should be grounded to reduce electrical noise and interference.

This article uses the Mitsubishi FX2N series PLC and the Omron E6B2-CWZ6C rotary encoder as examples to demonstrate the hardware connection process. For other PLC models or when using high-speed counting modules, it's recommended to consult the respective user manuals. To accurately interpret the counter values, refer to the high-speed counter section in the Mitsubishi FX Programming Manual.