This is an introduction and tear down of a couple of Arduino based industrial PLCs that RS-Components provided for me to review and tryout in various projects
The brand is "Industrial Shield" and they are from a company in Barcelona, Spain called "Boot and Work S.L."
One of the really cool things about these PLCs is that they are based on Open Source Hardware in the form of an Arduino Leonardo or the Arduino MEGA2560... yes the real thing, no modifications aside from providing an industrial strength interfacing circuits around them, wrapped up in a nice industrial DIN rail mountable package including full 24V operation, 0-10V analog in and out as well as isolated relay outputs and OPTO isolated digital inputs and outputs
These modules come in a variety of sizes ranging from 19 I/O through to 58. and that is just within a single module. 
ALL modules fully support I2C, SPI, MODBUS, RS485, RS232 etc. and as such can be expanded to the limit of those bus limits and of course the size of program space.
the ATMEGA based M-Duino modules also sport an Ethernet port further expanding on its capabilities including WEB interfacing, HMI interaction and Smart Device remote control
Basically these Industrial PLCs are limited in capability by your imagination and in follow-up videos I will be exploring some of these capabilities including interfacing to my CNC project, interpreting the G-Code into X, Y, Z motion instructions for the CNC with optional VFD control
The RS Details can be found here:- http://uk.rs-online.com/web/b/industr...
With their intro marketing video here:- https://www.youtube.com/watch?v=b4u5_...
Industrial Shield community site is here where the community pages provide many example projects users have completed using these modules: - http://blog.industrialshields.com/en/...