Conrad sells AVR based small PLC (programmable logic controller) that was already mentioned in this thread: https://www.avrfreaks.net/index.p.... I wonder if JTAG connector is already on board :-). Basically, most of the hard work has been done by company called Crouzet.
http://www.conrad-int.com/websal...
http://www.crouzet.com/millenium...