Interfacing Rotary Encoder to Mitsubishi FX5U PLC

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Interfacing Rotary Encoder to Mitsubishi FX5U PLC


Interfacing Incremental Rotary Encoder to Mitsubishi FX5U PLC by utilizing High Speed I/O.


            1) Mitsubishi FX5U PLC

            2) Incremental Encoder

            3) 24V SMPS

Software Required:

1)      GX
Works3 (Version 1.054G)

PLC Diagram :

Interfacing Rotary Encoder to Mitsubishi FX5U PLC
Interfacing Rotary Encoder to Mitsubishi FX5U PLC



1) Start the GX Works 3, and create new project.


2) 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.


3) Enable Channel 1 (CH1) and Channel 2 (CH2) by selecting > Use/Not Useto ‘Enable’ from drop down list.



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



5)      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.



6)      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.



7)      Create Ladder program in main program body as shown


8)      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.


9)      After download is completed, reset the PLC


10)  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.



We understood the working and Interfacing of Incremental Rotary Encoders to Mitsubishi FX5U PLC and also, we verified the output count.


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