I like to know the advantage and disadvantage of using sinking or sourcing? What's the reason to use sink and source? Is it also same for PNP and NPN? I like to know the reason why choose sink or source, sink and source
Thanks

I don't have a preference either way but usually when I buy sensors I try to get them PnP/NpN combined (Dip switch or jumper). That way I don't have to stock (2) of the same sensors with the only difference being the Sink/Source.

For us the primary concern is when a grounded DC supply is used. If so the inputs and outputs should switch the ungrounded line.

Thus if the minus side of the DC supply is grounded then PNP inputs (sourcing) and outputs whould be used to prevent errors possible due to an unexpected grounding of either the input or output line.

If the grounded line is being switched then a false true input or false true output takes place in event of a short circuit to ground.

Good summary "B". I've also noticed that sink/source can be a systemic or national thing. A majority of Omron and Toshiba systems I worked on in the 90's came from Japan and were sinking with a grounded positive terminal. When I went to work for a "Detroit" connected concern in 2000 everything was AB and setup Sourcing.

The terms source and sink are not the same across different parts of the world. Hence the reason that most folks adopted the terms NPN and PNP.

Typically I ground the DC common bus, and switch the positive voltages across everything. So read your manuals closely and follow the same. If you don't do this, then you could run into trouble if your DC bus ever "floats" on you. And you may not trip the fuses/circuit breakers if you are running an ungrounded system, making troubleshooting a nightmare. Imagine a chafed wire touching a conduit or fitting some place with an ungrounded system and what kinds of strange voltages could be all over the place.

This has been discussed in previous posts in detail. Check out the following posts.

NPN vs. PNP

pnp or npn sensors

Ground the 24VDC Power Supply Common?