Inductive Sensors - PNP vs NPN - N.O. vs N.C. - Datalogic

In this video we go over the basics of what an inductive sensor is and how they work. We also define the difference between momentary and maintained switches, NPN and PNP transistors, and normally open verses normally closed switches.

[nullfield]

I needed to know this, and watched a couple of videos.

This is the best explanation in the shortest amount of time without skimping on important details that were crucial for me to really get it, kudos!

[industrialautomation]

To better understand it, in NPN sensor drawing (4:16), top part is actually PLC input (could be relay or something else). There is permanent 24VDC on PLC input and wire going from PLC input to sensor is going to the collector of transistor which is switching negative (N pn - switching negative).

If you take DC voltage multi-meter and connect black probe to 0VDC and red probe to PLC input and there is 24VDC, that's mean you have to use NPN sensor. On other side, if you want to test the sensor, connect red probe to 24VDC and black probe to sensor output, if multi-meter display 24V, then it's NPN sensor. Sensor have to be in ON state of course.


IN PNP sensor drawing (4:16), bottom part is actually PLC input (could be relay or something else). There is permanent 0VDC on PLC input and wire going from PLC input to sensor is going to the collector of transistor which is switching positive (P np - switching positive).

If you take DC voltage multi-meter and connect red probe to 24VDC and black probe to PLC input and there is 24VDC, that's mean you have to use PNP sensor. On other side, if you want to test the sensor, connect black probe to 0VDC and red probe to sensor output, if multi-meter display 24V, then it's PNP sensor. Sensor have to be in ON state of course.

[michaelcoxfitness]

I need to watch this video again loads of information! Thank you for the video.

[mrbookends]

Thumbs up for that awesome Toyota MR2 turbo at the stop light!

[sriramgoutamputcha]

Thanks, the video was good. I have two questions:
1. Why do I need an oscillator to generate magnetic field? I think current through a coil is enough
2. Why the amplitude of is oscillation gets dampened when metal comes in contact with the magnetic field?

[Devloper]

thank you nice explanation ## thanks again

[TheCalibso]

Too many thanks, you're help me to understand

[MrVlax]

I have just one question: Where can i get this keyboard with cruise ctrl??

[Sham_samuraui]

can you show the internal components of the proximity switch and how its working in detail. Does all the proximity sensor will have switch itself or externally need to connect

[kennethenrico]

Can you adjust the distance sensing of the inductive sensor? Say for example, 1 inch away from the sensor, would it be able to detect the object? Thank you in advanced for the answer.

[RixtronixLAB]

Nice video clip, keep it up, thank you for sharing it :)

[azizullah]

how NPN and PNP relates with concept of sinking and sourcing?

[deepakkumarparida]

Is there a clear advantage of NPN over PNP? Or they are suitable for different purposes? Can U give some examples?

[gsharmand]

It looks like these sensors have a low sensitivity. The sensing distance is 5 mm or even less. Is there some way to have a 25 or 30 mm distance for sensing very small metallic objects like 1-2 mm dia screws/nails ?

[jacek-jan]

How about 110/230V AC sensors? Are they PNP and NPN too? And does it matter if they are connected to L or N?

[govindraj]

Kindly tell me difference between sourcing and sinking with practical purposes

[stalinsubbiah]

crown cork is stainless steel type of material then how it isattracted by inductive proximity and refro reflective photo sensor?

[mikewilson]

What about PNP/NPN 3 wire sensors? Efector offers a lot of sensors that say PNP/NPN but the wiring isn't a plug n play the way you would think.

[Travelwith_Joe]

Hi what is the name they tool you use to turn on the sensors?

[Limeayy]

i want to know how much voltage for a ECU in a automotive vehicle is required to turn on the base, i heard 5v is short to ground or something..?