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

A rotary encoder is a type of photoelectric device used to measure angular displacement and convert it directly 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) for processing. The PLC then uses its high-speed counter function to count these pulses, and the data can be displayed or monitored using an OMRON touch screen.

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

As shown in the diagram, this is a typical wiring setup for a two-phase rotary encoder connected to a Mitsubishi FX2N series PLC. Understanding how these components interact is essential for accurate signal interpretation and system performance.

The encoder typically has four wires: two for pulse outputs (A and B), one for the common (COM) terminal, and one for the power supply. Depending on the model, some encoders may also include a shielded wire for noise reduction and electromagnetic interference (EMI) protection.

The power supply for the encoder can either be an external DC source or directly taken from the PLC's internal 24V DC power supply. It’s important to connect the negative (-) terminal of the power supply to the COM terminal of the encoder, while the positive (+) should be connected to the encoder’s power input. This ensures proper operation and prevents signal distortion.

The COM terminal of the encoder is connected to the corresponding COM input terminal on the PLC. The A and B pulse signals are directly connected to the PLC’s input terminals. When connecting, it's crucial to consider the PLC’s input response time, especially when dealing with high-speed applications. If the encoder has a shielded wire, it should be properly grounded to minimize electrical noise and improve signal integrity.

Description: This article provides an example using the Mitsubishi FX2N series PLC and the Omron E6B2-CWZ6C rotary encoder to demonstrate the hardware connection process. While the wiring method described here is specific to these models, other PLCs or encoders may require different configurations. For more complex systems that use high-speed counting modules, always refer to the manufacturer’s technical manual. To accurately interpret the counter values from each terminal, consult the high-speed counter section in the Mitsubishi FX Programming Manual for detailed instructions.