Control PLC with SLMP over ethernet

Thread Starter


Joined Nov 29, 2020
I did a lot of research for being able to control my Mitsubishi FX-5U PLC.

I want to control it over network using SLMP with 3E frame messaging, but I am unable to understand the message frame.

I am referring this manual. But despite spending days I haven't been able to understand how to control the PLC using SLMP.

I understand that if I use this message frame, I will be able to read data on D200 register, and it does work successfully.

50 00 00 FF FF 03 00 0C 00 10 00 01 04 00 00 C8 00 00 A8 01 00

But, I just don't understand, how to access and control the devices on X and Y. Lets say I have to read data from all inputs (X) or write data to all/few output (Y) at once.

I tried resolving this issue by trying to write to outputs, Y1 and Y2, and set them to high, but it doesn't work (Below frame is in ASCII format)

50 00 00 FF FF 03 00 0D 00 00 10 14 01 00 01 Y* 00 00 01 00 02 11

I know I am doing it wrong, so want to know really what am I doing wrong. A code snippet is very much appreciated.