Experimental Physics and
Industrial Control System

Kyle Lanclos <[email protected]> · Thu, 25 Aug 2016 15:41:07 -1000

Hello everyone--

I have a small project that involves capturing telemetry from a
Mitsubishi FX3GE PLC. I need to access the device over ethernet. This
is turning out to be a bit of a deeper dive than I expected; my
limited understanding is that the non-Modbus ethernet interface only
supports the MELSEC Communication Protocol (MC Protocol), a more or
less proprietary communication format.

A reference manual for the MC protocol can be found online:

http://dl.mitsubishielectric.com/dl/fa/document/manual/plc/sh080008/sh080008w.pdf

One can find OPC servers that speak this protocol; one can also buy a
Modbus-capable interface for the PLC. I found mention of an EPICS
driver developed 10+ years ago by a group in Japan:

https://accelconf.web.cern.ch/accelconf/ica03/PAPERS/WP563.PDF
http://www-acc.kek.jp/WWW-ACC-exp/KEKB/control/KEKB-Control-home.html
http://www-acc.kek.jp/epics_gr/products/NetDev/netdev-man.html

...but I can't find the source code for the driver, and the device is
not listed on the hardware support list:

http://www.aps.anl.gov/epics/modules/manufacturer.php

If anyone has any knowledge of open source software interfaces that
are available for these Mitsubishi PLCs I would love to hear more.
Using EPICS is not a strict requirement for this application.

Thanks in advance,

--Kyle

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System