Sinking and Sourcing PLC Inputs with PNP NPN Sensors

hi this is Tim and today we're gonna talk about syncing sourcing NPN PNP and how to determine what type of sensor you need for your PLC input before we get started please take a moment to subscribe and tap the bell so you get notifications about our videos and click that like button it does a lot to keep us energized making these videos and do these videos also going to show you the power of your comment to change the course of our videos I posted this image over on Instagram LinkedIn and all the other social things mainly just to tell you about a video that was coming up and I couldn't believe the amount of conversation they ended up in those post two in particular stuck out that really showed the confusion over syncing and sourcing Mike Regan said source flows towards negative and sink was flow towards positive and then another person named Aaron Kumar said source provides a path to plus Singh provides a path to minus now both of these guys are right but when you put their answers side-by-side you can see how you can quickly become confused by these terms so the original intent of this video was to clear up syncing and sourcing using this basic template one of my Controls friends Jeremy Ross pointed out that syncing and sourcing is not always the same depending on your PLC manufacturer and at first when he said this I said well that is simply because one is talking about plc inputs and the other is talking about the sensors connected to it but when I got looking at it I found out that he was correct about 90% of major PLC's manufacturers defined syncing and source in one way and about 10% of them define it the opposite way then one manufacturer really confused me because they define PLC outputs seeking and sourcing the way the 90% of the PLC market did but their plc inputs they defined the way the 10% did so they flip-flopped and finally one manufacturer and I'm not going to anybody in particular but halfway through the same user manual they went from defining secretive sourcing one way to the exact opposite way but with that comment from Jeremy this video quickly went from a basic this is sinking this a sourcing type video to a much deeper video of here or how PLC input and output circuits work and here is how to take the diagram from the PLC manual and figure out what sensor you need so we're gonna start off a really broad this is sinking this a sourcing PNP NPN based off of that 90 percent crowd but then I'm gonna go through how exactly to look in your user manual and figure out exactly what type of sensor you need for your application two other notable comments are one was from Ronald steed he stated that these were often the source no pun intended of confusion in the industry he gets kudos for helping us with our title also one commenter pointed out that I had left my load and input out of my diagram and that's why I couldn't figure it out he was sure to tell me at the bottom of his comment that he was an electrical engineer guys leave your credentials out of your comments especially when you're making a Captain Obvious type comment since they were left blank so that I could plug in the various different circuits for this video we are gonna use an Allen Bradley 1769 L 16 compact logics PLC and a 1769 L 24 compact logics PLC and the main reason is this PLC has strictly syncing inputs and sourcing outputs and this one the inputs and the outputs can be sinking or sourcing so these are the two very common set ups you'll see no matter what PLC brand that you're looking at so let's start with our basic circuit diagram and here's our power supply which has a plus and a minus you see I have a blank here and it's gonna go around and I have another blank here and for the majority of applications one of your items will be sinking and one will be sourcing also depending on your diagram you may actually see this symbol here instead of this symbol this is a battery symbol but it's used very often on circuit diagrams so both of these can be considered the same also this is an AC circuit we're not doing AC in this video this is strictly about DC Circuit's so going back to this for the bulk of your applications if you know one you can figure the other out in the case of our compact logics PLC the l16 it has sinking inputs so in that case if we put our PLC input here as sinking then we need a sourcing sensor to go along with it now if you're not quite following this it's okay we're gonna go with more in-depth we're gonna actually pull up the diagram for this and I'll show you how I figure it out exactly now for the outputs they are strictly sourcing so we can do the same thing on our output and we can plug in our PLC output is sourcing so that means our load needs to be sinking and we'll go through some details of exactly what that means now in the case of the l/24 it can actually go sinking or sourcing so if we wanted our plc and puts wired sinking we can plug them in and we would know that we need a sourcing sensor whereas if we wanted our PLC enthis to be sourcing then we would know we need a sinking sensor or the opposite is true also let's say you have an application and your sensor is already SPECT then if you had sourcing sensors then you know you need to wire your PLC inputs as syncing or if you had syncing sensors you would know you need to wire your PLC input as sourcing but how do you actually wire things elicit the easy one first and that is your contact closure so that would be your push buttons your limit switches I really in it well in even any sensor that as a normally open or normally closed contact that is complete let's say is completely isolated and let's say that we're gonna wire to our L 24 and we're gonna wire it sourcing in that case we have a PLC and put the DES sourcing so our PLC input will have plus 24 on it and it's gonna feed 24 to our contact closure and then on the other side of it we're gonna need to connect to the negative sourcing peels the input you connect the PLC input to one contact and the minus your power supply to the other whereas the l16 or if we were doing this one syncing then it would look like this so you would send power to your contact closure which again is your push button your limit switch whatever and then the other wire that would go to your PLC input and then usually through the common terminal or in this in the case of the L 16 which we'll look at closer in a second it's called a field terminal it would go on to the minus so that's really easy that's your contact closures where the issue starts to come in is when you have an actual sensor like this so what is a syncing sensor and what is a sourcing sensor the real basic answer is a PNP sensor is going to be a sourcing sensor and a NPN sensor is going to be a seeking sensor PNP is positive negative positive and NPN is negative positive negative but a guy told me way long ago actually it was a coming he is a competitor man there you go competitors make sure that you help grow the next generation he said to think of PNP has power and NPN as not power and that's always stuck with me so I know if I have a PNP sensor that is going to send power out or plus out which is going to come on around to our PLC input and then on to our minus and if I have an Indian sensor it's going to be not power so here we already have power it's going through our input and we're going to come around and it's going to take it to our minus of our power supply we're gonna go through these a little more detail in the wiring diagrams now all right so we're gonna start by looking up the L 24 just because it shows both ways you can wire it that's a 1769 well 24 yeah that's its manual and all right okay and this actually has so this manual right here actually has both the L 24 and the L 16 on it and let's just see if we can quickly find what we're looking for let's just look for the word sync and okay that's talking about the L 16 all right and here we are so here are the L 24 s n plus here is closer but we're looking at so here is our DC n and there's comm 0 and comm 1 and then here is our 16 outputs and again you have coms 0 and comm 1 so these are broken up into groups of eight so you have eight inputs that are 0 through 7 and another 8 that are 8 through 15 and they can be wired differently so you can actually wire half of these syncing half of them sourcing and same down here you can wire your outputs half syncing up sourcing let's say here's what we're looking at on that diagram and right here you can see here here is that coms 0 so this is that first group of seven and here are the inputs connected to it and depending on what you wire to each of these determines whether it's syncing us or sourcing so if we're going to use this as a seeking input the same as we're actually using it over here on this L 16 then we're going to want to put plus 24 volt to each of our sensors and then the other side of our sensor is going to go to the PLC input and then internally all these are going to go around and they're going to come back to this common this calm zero and then since we wanted to be sinking we're gonna put this to the - DC now if you did want to do these sourcing then you would simply do the opposite you would be the negative DC or the zero boat of your power supply to each of your contact closures and then the other side of those to the plc inputs and then internally they would loop around a comma zero which would now be connected to the plus 24 volt of your power supply okay and I just realized and here's why it's great to look at the wire diagrams to know for sure is I told you that these could be sinking or sourcing on the outputs but now that I look closer they can so here for the outputs they are strictly sourcing outputs or they're gonna be sending 24 volt out so here we have plus 24 volt going into the V plus terminal and then comm 0 is going to the minus 24 volt terminal and then each output is going to go to its load with plus 24 volt and the other side of your output is going to go back to the minus DC so the inputs on it can be sinking or sourcing but the outputs are strictly sourcing on this now for the L 16 it is pretty much just the sinking side so the L 16 you're going to be 24 volt to your switch and then the other side of your switch is going to go to your input and then in the L 16 s case it has these field power connections and it's FP plus FP minus and you just put plus 24 volt to the FP plus and minus 24 volt to the FP minus but they do not have the option of switching so in this case you do have to make sure you have the right type of sensor and that's gonna be a sourcing sensor or a PNP sensor about PNP and NPN that's the one thing I don't think I've covered much of P and P sensor that's gonna be power just remember the P stands for power so it's gonna send plus 24 gold out the NPN no power so it's going to sink power into it so I think that pretty well covers how to wire the PLC then one question that we still have to address is what type of sensor do you need now for the 90% category if it says that it is a sinking input then you'll need a sourcing sensor if it says it is a sourcing input you'll need a sinking sensor but if we go back and we look at this diagram we can figure it out pretty fast even without that so right here if we feed plus 24 volt to our switch and then we're going to our input then we can kind of go back to our diagram and plus 24 to our sensor which could be that switch that they're showing there it's going to go around so we have a PLC sinking input and we need a sourcing sensor oppositely if we had negative going to our sensor then we can look and ok we have negative going to our sensor and then we're going on to our PLC input then our sensor would be sinking now we know we need a sourcing or a sinking sensor how does that equate to pnp and npn very layman's terms here a PNP you can think of as power NPN no power so the PNP is going to send power out or be the source of power so this would be a PNP situation at the end no power so it's going to be on the minus side so this sinking sensor would be an NPN now another question I get a lot is why do we have NPN PNP versus sinking and sourcing and I'll tell you the honest truth I don't know I just arbitrarily went and grabbed a sensor so this is a sensor just like we're talking about here it says source sync on it which just seems to make so much sense to me but some of them don't so i'm use the terms NPN PNP the O and the other question do get a lot is which is better PNP or NPN or which should I use in the case of the L 16 you're gonna want to use PMP because it's the only thing well that will work with this PLC and that's probably the best way to think about it is not which one's wet better but which one fits your application beyond that they're pretty much gonna perform the same there are people who argue that you shouldn't use NPN because if you short it to ground it turns an input on which could do something unsafe there are people that argue against PMP because you could short it to ground and burn something up and I'm gonna stick with figure out what's good for your application now there is one exception and honestly I didn't know enough about this to put it in a video but I did see some claims and it looks like it is true that I don't understand the electronics behind it that NPN sensors can operate faster than PMP and so that's why I think a lot of times you do see your high speed applications more Indian but that's that's I have no basis off of that so I can't tell you for sure now I think that about covers everything thank you to our patron supporters who did fund the making of this video also thank you to Mike Reagan's arun kumar jeremy everybody who met turned this from a two-minute video to what's probably a 25 minute video at this point and again your comments matters so put any questions you have about this in the comments be sure to tell me what you'd like to see next again and I can't stress to you enough how much we appreciate you subscribing and liking our video also YouTube thinks that you should watch this video next and here's some similar videos we have on our Channel till next time hi this is Tim and this is Amber of TW controls we run the automation store be sure to subscribe for more great videos and like this video and comment on what you would like to see next visit our website where we offer a full line of PLC's simulators control panels PLC trainers and more

Channel: Tim Wilborne

Views: 57,132

Keywords: sinking and sourcing, sinking and sourcing plc input, sinking and sourcing plc, sinking and sourcing npn pnp, sinking and sourcing outputs, sinking and sourcing sensors, sinking and sourcing explained, Sinking and sourcing plc output, sinking and sourcing concepts, sinking and sourcing transistor, PLC Inputs, current sinking and sourcing explained, Sourcing and sinking logic, Tim Wilborne, programmable logic controller, Sensors, industrial automation, allen bradley plc training

Id: VFdtz3q4as8

Length: 17min 30sec (1050 seconds)

Published: Wed Nov 06 2019