The Ardbox PLC is a din rail compact industrial controller built around an arduino Leonardo by Industrial Shields. This type of device provides a convenient bridge between the free to use and open source arduino development capability and 24V industrial controls. It’s similar to what I hope to achieve with my esp32 PLC, though I think I’ve come up and will come up more interesting additional capabilities.
The price of this solution is hard to beat for its range of capability. As a connected device, the Ardbox is quite limited (though by no means useless), but as an independent single machine controller, it excels, and it doesn’t require expensive proprietary development software. Don’t get me wrong, that proprietary software can be extremely useful for developing large machines which rely upon network attached sensors and other controllers. But for a simple, pantry sized machine with hardwired sensors and drivers, the Ardbox provides a good cheap way to get it done, which is always highly desirable.
One drawback of the Ardbox is a lack of programming security. It’s ease of development and programming translates to a need for physical security of the device to insure preservation of the program as is where such is critical for safe operation of a machine.