The board is using 16 (8*2) screw terminals (3.5mm grid) for the outputs and is also using an additional set of 16 (8*2) screw terminals for the inputs and power.

And some simple scenarios:

To control, say, the standard 24V DC for use with industrial applications you just power-up with 24V on terminal no. 15 (+) and 16 (-) on the input side and let your sequence / code control the output solid state relays as you want. Next, if you want some industrial 24V photoelectric sensors - just connect it to the power and a input terminal on the board. Now you can also check the status of the sensor in your sequence.

And now, if you want to monitor or control everything using a PC or similar, you can connect the computer directly to the Nidingen Board using a USB to Serial cable (can also be used to reprogram the board, see below). Or if you instead prefer to make the Nidingen Board a stand-alone "Internet-of-Thing" you can connect the board to the network using a cable, or WiFi, for example - this is made possible using one of the different shields (yes, a bit like the Arduino shields) that is available (see below).

You can also make your system use a simple, but effective, touch-screen for presenting status, change parameters, control outputs and so on. Support for this is already built-in "out of the box" - just to let you start doing the creative magic instead of the basic "boring stuff", because, well, one of the concepts behind the Nidingen Board (and its perpherials) is to simplifie things as far as possible and let you start doing your things/ideas within that minimal "start-up-time". :)

Only through-hole components used so it's a fairly "easy" job if you have the time and skill. ;)