Passive Distribution Blocks

This is an example of what I'm talking about:

What do people usually use this for? Like which protocols? Profibus? Modbus? DeviceNet?
They often have M12 connectors that are A-coded or B-coded that have 4 pole or 5 pole.
A lot of times if it's 5 pole you'll find that pin 1 is supposed to be V+, pin 2 is N.C., and pin 3 is supposed to be V-.
Why would they specify that on there? What standard are they adhering to, if any?
Hi dear friends,

I have a project and need your advice,

I want to commission this project with AC900F and have a lot of signals non-redundant and redundant,

Please advise me about the limitation for cards (redundant or non-redundant) in every nod. Because, for example, I can implement 15 redundant cards(AI845) in one nod but I am not sure if it's good or not!

Thank you
These ones don't appear to be used for protocols, only for sensor signals. The pin arrangement on each of the connectors (M8 or M12) is a result of how many pins are available in the main harness.

For example, the one you linked to has a panel-mount plug in the back, and each of the M12 connectors has a +, -, and two signal conductors. So with 8 ports, you get 16 device options.

Some of those models have a 12-pin harness connector (like this one: so looking at the datasheet, it has 2 signals for the first two sockets, but only 1 signal for the other6 sockets, so that gives you 10 signal wires, plus the +/- for the input power, and there's all 12.

So the purpose is to get one 12-conductor wire harness span from the controller to a distribution point on the machine for simple discrete I/O only (in contrast to like IO-Link or a com protocol).