Greetings Maintenance Man ...
before we go any further with the “positive electrons” idea, let’s look at the picture below ...
suppose that you have a SOURCING-TYPE PLC input module (for example type 1746-IV16) ... that module would play the part of the “LOAD” in Figure A above ... the solid-state sensor that you’d need to connect would be a SINKING-TYPE sensor - also known as an NPN-type sensor ...
notice that the description above gives us ONE “sourcing-type” device and ONE “sinking-type” device to use in our circuit ... the “sourcing device” goes on the PLUS/POSITIVE side ... the “sinking device” goes on the MINUS/NEGATIVE side ...
now then ...
suppose that you have a SINKING-TYPE PLC input module (for example type 1746-IB16) ... that module would play the part of the “LOAD” in Figure B above ... the solid-state sensor that you’d need to connect would be a SOURCING-TYPE sensor - also known as a PNP-type sensor ...
notice that (just like before) the description above gives us ONE “sourcing-type” device and ONE “sinking-type” device to use in our circuit ... and (once again) the “sourcing device” goes on the PLUS/POSITIVE side ... the “sinking device” goes on the MINUS/NEGATIVE side ...
going one step further ...
now instead of input modules suppose that we talk about the PLC output modules instead ...
suppose that you have a SINKING-TYPE PLC output module (for example type 1746-OV16) ... that module would play the part of the “SWITCH” in Figure A above ... the “LOAD” that you’d need to connect would be a SOURCING-TYPE field device ...
notice that (as before) the description above gives us ONE “sourcing-type” device and ONE “sinking-type” device to use in our circuit ... and (once again) the “sourcing device” goes on the PLUS/POSITIVE side ... the “sinking device” goes on the MINUS/NEGATIVE side ...
now then ...
suppose that you have a SOURCING-TYPE PLC output module (for example type 1746-OB16) ... that module would play the part of the “SWITCH” in Figure B above ... the “LOAD” that you’d need to connect would be a SINKING-TYPE field device ...
notice (again) that the description above gives us ONE “sourcing-type” device and ONE “sinking-type” device to use in our circuit ... the “sourcing device” goes (as always) on the PLUS/POSITIVE side ... the “sinking device” goes on the MINUS/NEGATIVE side ...
nailing down the “big picture” ideas:
your basic DC circuit needs ONE “SOURCING” type device - and ONE “SINKING” type device ... the “SOURCING” device always goes on the PLUS/POSITIVE side ... the “SINKING” device always goes on the MINUS/NEGATIVE side ...
survival tip: don’t think of the words “source” and “sink” of telling where the “juice” is actually coming from - and where it’s going to ... instead just remember that the “source” thing goes with PLUS/POSITIVE - and that the “sink” thing goes with MINUS/NEGATIVE ...
is it starting to come together? ...
I hope this helps ... and I apologize in advance for any Copy-Paste errors I might have made - I’m pretty tired at this time of day ...