Mitsubishi Serial Communications


Thread Starter

Matyas, Tom

I have been assigned the task of creating a serial communications driver to interface our motion controller product with the Mitsubishi MELSEC line of PLCs. I am having a difficult time finding any specific information on the
protocol that is used. Is the same protocol used to communicate to all series( ie. A, FX, Q, etc ) of MELSEC PLCs or does each series use a
variation of some base protocol?

Can this protocol specification be purchased/download? Is there a developer's toolkit available?

Any help/comments/links would be appreciated...

Tom Matyas
Software Developer
Automation Intelligence
Duluth, GA 30097-4902

Michael Dannhardt

Mitsubishi has the protocol(s) documented in the hardware manuals for each associated interface module. Contact Mitsubishi and they should be
able to give you the part number of the user manuals.

Anthony Holland

What PLC are you using? Several of the PLC can used protocol or non-protocol. What are you talking to?

I have some info, let me know the plc you are using and I'll try to help.

We use Mitsu to talk to PC's and scanners in the package handling industry.


Hi Anthony,
Can I ask you a question? How do I send a protocol query over to the PLC. I am not good with bits and hexadecimals as you can see. I don't understand what is the query doing or how does it work.
Currently, I am using a mitsu melsec A PLC and I would certainly be grateful if you can help out. My email is [email protected]

Thanks and Regards,
Xu Weijie