Interfacing Rotary Encoder to Mitsubishi FX5U PLC
Objective:
- Interfacing Incremental Rotary Encoder to Mitsubishi FX5U PLC by utilizing High Speed I/O.
Hardware:
1) Mitsubishi FX5U PLC
2) Incremental Encoder
3) 24V SMPS
Software Required:
- GX Works3 (Version 1.054G)
Wiring Diagram :
Connect both A and B phase of Encoder to X0 and X1 input of PLC

Procedure:
- Start the GX Works 3, and create new project.
.

- In the left navigation panel expand options as follows:
Project > Parameter > FX5UCPU > Module Parameter > High Speed I/O.

Click on Detailed settings in front of High Speed Counter Option.
- Enable Channel 1 (CH1) and Channel 2 (CH2) by selecting > Use/Not Use to ‘Enable’ from drop down list.

- Set the pulse input mode of both CH1 and CH2 to ‘2 Phase 1 Multiple’ as shown.

- Expand Input Response Time from Module Parameter navigation in left.

Set the Response type for X0 to X7 to ‘High-Speed’ and set response time to ‘No Settings’ for X0 and X1.
- Click the Check button, and the No Error Found Dialogue should pop up. If so, Click Apply and proceed further. If no, click Restore Default Settings and Set up again.
- Create Ladder program in main program body as shown

- Build all and download the program into PLC including modified CPU parameters.
Select ‘Parameter + Program(F)’ and then ‘Execute’ and wait for the download to finish. After the Download is completed, Reset the PLC.
- After download is completed, reset the PLC
- Verify the Count in SD4500 register in the PLC memory by rotating the encoder shaft to a full rotation .This count should match with PPR rating of encoder relative to initial value of counter and direction of rotation with respect to its sign.
Conclusion:
We understood the working and Interfacing of Incremental Rotary Encoders to Mitsubishi FX5U PLC and also, we verified the output count.