All this internal wiring...

[Singapore_Mats]

I installed a small expansion card for a S7200, 4*DO, and it need
voltage on eight places! Why couldnt siemens supply this internally... should have saved a lot of time...

 

[jacokapp]

I dont know the s7-200 modules that well but the new s7-300,400 you only give one supply voltage per output card the rest is done internally.

Why do you need to supply 8 places with voltage?

 

[Singapore_Mats]

0M, 1M, 2M and 3M need -24V and four more for the plus. Its a relay
card, 4 I/O.

 

[tragically1969]

Because some people may want to swithc different voltages, hence the different commons ?