Home / Factory I/O / Getting Started
Description
An overview of how the various discrete sensors work in a Factory I/O scene.
Transcript
(00:01) I want to take a minute to just kind of show a little bit about the sensors that we work with in the lab last night we worked with the reflective sensor that was the sensor that came by default in that first scene and second scene the scene A to B and what we saw last night was the sensor was kind of acting opposite of what we were expecting or at least I had kind of put a normally closed contact and I um unfortunately he had made the wrong assumption myself I didn’t realize and then um because I never had didn’t quite test it before
(00:36) and the reason for that is is kind of simple actually when we sort of think about this kind of logically and that is just understanding you know these sensors themselves and and how they how they behave so a reflective sensor so these are all discrete sensors and some of you are in the industrial Electronics class and we discussed these sensors in that class so here we get to see them in operation but the reflective sensor is a sensor that it’s a light beam and it gets sent out and it bounces off a reflector and comes
(01:13) back being that it bounces off the reflector and comes back then the sensor is actually kind of should we say triggered it sees the light beam coming back so therefore it it sees its reflection and it’s saying hey um I’m I’m triggered and it works in a manner where when the reflection does not come back then the sensor basically gets you know it it’s off the sensor goes off essentially so so basically it’s always on as long as the light beam is properly coming back then it’s always on and then when the light beam gets
(01:50) broken then the sensor gets turned off so it kind of worked a little bit opposite of what we might have expected there um you know kind of from our what our intuition might have told us but there are two other types of discrete sensors that we could have potentially used in this scene um that were available in Factory IO when you go to the factor i o we see sensors and and hear all the available sensors um to the few different types so so there are there were two proximity sensors that we could have picked from
(02:26) there was this capacitive sensor and this inductive sensor and again kind of kind of crossing over into the industrial Electronics class we learned about the inductive sensor being that it’s looking for something metallic it’s gonna you know an electromagnetic induction based on on some chunk of metal passing in front of it so these boxes in our scenes are where it was plastic um so an inductive proximity sensor would not have worked for us in this application so the other one that we could have considered is the capacitive
(03:01) proximity sensor the capacitive proximity sensor can detect um other types of material not just metal it could it can trigger on plastic or cardboard or wood oh it just sees you know through its you know it just sees um the capacitance of an object as it’s Crossing versus when nothing’s there and it can trigger so so we could use that sensor the third type we show here is is a diffuse sensor so the fuse sensor is uh is similar to the reflective sensor in that it’s a light beam the difference is that there’s no reflector so in this
(03:40) case the light beam is getting sent out but it has to bounce off of an object to come back so the light beam will have to bounce you know off of the box so when the Box crosses its path the light beam will have something to bounce back off of and that’s when it gets triggered so when it sees the light beam come back to it like a boomerang when it sees the light beam come back that’s when the sensor activates because it sees its Light Beam come back so the fuse sensor is nice in that we don’t have to have a reflector
(04:17) but we do have to kind of consider the material um that the the sensor is is bouncing the light off of if the bounce if the material isn’t really very reflective then it may not properly sense that object now one thing I was kind of nice to see you know if you were kind of setting up these scenes you see these you know I’m in the offline mode right now we see these red dashed lines going on so this is actually indicating the sensing um distance or depth of this of that it can sense so in this example of the capacitive sensor we could see that it’s
(04:58) not a very far distance this is actually the maximum sensing distance for this uh device so if I kind of just click on it to activate it I can see that I can actually adjust its sensing distance but this is as far as it goes just a matter of a few inches out from the sensor whereas our our light sensors have the ability to go further out as well as dial it back in So this one I just had kind of triggering across the entire beam or I’m sorry the entire conveyor and the same thing with the reflective sensor I could actually take
(05:33) this reflector and and move it further back and we can get several feet um so we get a pretty decent distance with reflective sensors um you know the fuse sensor would be as you can saw it kind of capped out about right there so um so it you know you do get a decent distance but there is a cap to it whereas the reflective sensor can go a much further distance um for that light beam so this is just the um so I’m going to show you how this operates uh we’ve got the conveyor this is basically the same conveyor we were messing with in the lab
(06:11) last night we’ve got the box we got the conveyor motor and then what I have going on up here is I can actually look at the values of the um of these sensors and actuators too in this little kind of watch window up here I can just drag them up here and then I can actually Force the conveyor belt on just by clicking on it so I can kind of totally test this without having to be connected to a PLC I do need to be in the Run mode for this one other thing to note is I did slow down the speed of the simulation just to kind of help show
(06:44) this a little better so I’ve slowed it down half speed at the moment just to kind of let it run a little bit slower so when I go in the Run mode I’m going to go ahead and force on the conveyor in just one moment do I want to show that uh what’s Happening Here is I got an I got this kind of lit up orange indicator next to the reflector sensor and see how it is colored yellow here too so it is considering that the light you know that the reflective sensor is true or made right now um It’s on again it’s going to go off
(07:16) when the beam gets broken one other thing to show you is there are some indicating lights on these sensors which obviously are very hard to see when you’re not zoomed in but we have a green and a yellow light here so one of these is telling us that the um that the sensor is aligned the green LED is saying it’s aligned so basically it’s just saying hey you know I’ve got a uh you know I’m aligned with the with the reflector and the yellow one is saying that the the light beam is not interrupted so when the yellow light is on it is uh
(07:53) it’s at the beam the beam reflected back basically um the capacitive sensor doesn’t necessarily have an indicator on it and then the um the diffuse sensor does have a little LED on top of it that would light up when it gets triggered right now it’s not triggered of course so um we are in the Run mode I’m going to go ahead and force the conveyor on so we got our you see our belt is rotating we’re going to see our Box come into uh the scene here in just a second and I’m going to go ahead and pause it so I can actually pause the uh you can
(08:32) actually pause this and we’ll see that here we are the few sensor capacitive sensor reflective sensor so I’m just going to go ahead and uh unpause it and we can see now the uh that led went yellow I mean sorry it went red uh to indicate that it triggered we can also see that the diffuse sensor turned Orange so it is now considered on true I’m going to unpause this let it get to the capacitive sensor so now we can see the capacitive sensor has triggered it is on therefore it’s true indicated the box that there’s something
(09:09) is in its presence basically now the the back of this box has has cleared the diffuse sensor so it has turned off and the reflective sensor now has gotten triggered you can see we can’t see the reflector any longer and now it is basically dropped off out or off so um now we’re past the capacitive sensor so it has turned off back to off and if I go ahead and complete this box off of the table we see now that the reflective sensor basically turned back on because nothing’s breaking the light beam again so I hope that kind of helps explain why
(10:07) we had to do what we did with the context last night and how these behave it all came down to the fact that the reflective sensor being that the light beam is bouncing back is basically saying that hey I See the Light Beam therefore um I’m active or I’m on and then it has to be where the light beam is no longer reflected back and then that’s when it should always say triggers in this case turns off so there are a few other sensors here that we could consider in the application there’s a vision camera vision sensor this is what this is a
(10:47) camera so it’s a to be a more high-tech sensor we need for this type of detection there’s also these light arrays which if I were to put one in here you’ll see that this is more like a light curtain so it’s it’s an array of light that would line up to a receiver module on this end and basically if anything breaks you know any one of these beams get broken even the top one only or the bottom one only or any in the middle then it would trigger this whole light array so this would be designed this would be more for
(11:21) like a larger application like a larger box or something they can measure you know something breaking or the presence of like a person walking through this light like curtain light array so we wouldn’t really use this for this application either it’s just a little bit larger than we would need so so our three sensors down here could potentially do the jaw for us all right that was it just wanted to give a little uh I just want to kind of help show that a little better and maybe that helps visualize how these sensors
(11:53) operate um you as well