Photoelectric Product Overview Training

Hi, Scott and Darryl from Banner Engineering. Going through some basic photoelectric concept training.

So on this this module, we're going to talk about photoelectric construction and some basic principles behind photoelectric sensing.

Darryl, can you kind of go through some basic photoelectric stuff with us?

Sure. Thanks, Scott. So why would you use a photoelectric sensor over other technology?

Well, Photoelectrics offer many advantages. One is non-contact, so there is no mechanical part that needs to make contact with the target.

Therefore, nothing wears out. Photoelectric sensors can detect many targets at many different ranges.

Not only can we detect a target is present or absent. Today, our gaging devices can even tell you the distance that target is from the sensor.

That's important in some applications. We can detect as close as millimeters.

And even out to 700 feet. Another advantage is long life.

All of photoelectric sensors are solid-state and surface mount designed and all the banner products are industrial grade.

Meaning, that they are designed to work in harsh environments, so we can work anywhere from minus 40 C up to one hundred fifty eight F.

And we can take a lot of shock and vibration. And they are fast: one millisecond equals one-thousandths slices, 1000 slices in a second.

It's pretty standard that a sensor can operate at one millisecond, one slice in that one thousand.

But Banner has a sensor that can go down to ten microseconds. Now we're down to millions of a second.

And we can detect almost any target, whether it's a box, a car and a car wash.

Even if it's liquid, photoelectric sensors can detect a plethora of targets.

So there you have it, Scott.

So from a construction perspective, what do we have going on inside of those photo eyes that make them work? So there's an emitter and a receiver that makes them work.

But we're gonna get into more detail on that in the next slide. Excellent. Yeah.

And in terms of, like, how you set these guys up, are there different methods, different modes on how you actually do setup on these sensors?

Sure. And it really depends on the application and the sensor. So as you see here on the board, we have many different form factors.

So depending on the specific needs of your application, it would detect which sensor you need and how to set that up.

Excellent. Thanks, Darryl. Now wrap us up here on some basic photoelectric concepts.

In this module of basic photoelectric sensor concepts, we'll talk a little bit about the construction and how our photoelectric sensor works.

Darryl, can you walk us through a little bit of the construction on some photo eyes? Sure, Scott.

So each photoelectric sensor has an emitter and a receiver.

So we'll start off with the emitter. The emitter is the device that actually admits, like we call this an LED stands for light emitting diode.

What we do with these LEDs is we actually pulse them. We give them their own frequency.

And what we also do is with the receiver, we tune it to the emitters frequency.

The concept to help you get this is if you think of a radio, it can pick up many different stations.

But it only picks up the station that your radio is tuned into. Same with the receiver.

It will only pick up the frequency that of the emitter because that's what it's tuned to.

That way we can block out a lotta noise in a factory environment.

Visible red is very common and infrared is as well.

We typically go to visible red if we want the contrast.

We also have green and blue LEDs that help a contrast or if we want to aid in alignment, we'll go to infrared if we want long-range.

We also have lasers and Banner has class one and class two lasers. Class two is a little bit more higher power.

Just so you know, there is a class three, but Banner doesn't go there because it can pose an eye hazard.

So you can feel comfortable that if you ever use a banner laser device, it's only class two.

It poses no eye hazard. So, Darryl, you talked a little bit about that word modulation, you used that concept of a radio station.

Is that what helps us avoid getting interference from overhead lighting and other light sources?

Is that correct? That's exactly it, Scott. It's a very easy and efficient way to engineer a sensor, to ignore all the other light noise in a factory.

And do we do that with our LEDs as well as our laser sensors? We do it with all of our photoelectric products.

Exactly. Excellent. I've got a couple of examples here. Some different size photo eyes: our Q60s.

You can see we've got a very large format emitter-receiver on here. All the way down to one of our VS2s, our very small sensors, but the same concept exists there.

So whether you're working with something very long-range or a lot of power or something small for very close range.

The same concept applies an emitter and a receiver. And then using that modulated light that Darryl talked about.

Our module right now is going to be talking about how we apply all of these different sensors.

There's lots of different approaches, different applications, a lot of different modes that we can operate in.

Darryl, can you kind of go through the different modes that we have available in photoelectric sensing, how we may use those?

Sure, Scott. Thanks.

So, Banner, we manufacture a lot of sensors. So you may be wondering, well, how do you select the right sensor for the right application?

You start off by having to understand the modes. So we'll cover that a little bit.

So we're gonna start off with the opposed mode.

Opposed mode consist of an emitter which is in a separate housing from the receiver, which is also in its own housing.

Why we start with the opposed mode is because it offers the most excess gain.

I'll get into excess gain a little bit later. But in general, excess gain is the amount of light energy a sensor gives off.

More is better. So you typically want to start with the opposed mode.

And the way it works is when an object comes in between the emitter and the receiver, it changes the output on the receiver.

The next mode is retro or retro reflective.

You have the emitter and the receiver now in one housing, but you have another object that is called a reflector.

So the reflector shines at the emitter and receiver element.

And when an object comes in between them, it changes the output on the receiver.

This offers the second most amount of excess gain. From there we go to the proximity mode and we're gonna start off with diffuse.

Diffuse, once again, is a single housing, housing the emitter and receiver.

This simply spreads light out in all directions and a target that is out in the distance will send that light back to the sensor, turning on the receiver's output.

In that mode of diffuse, we also have a special variation of that: called fixed field.

The advantage there is, fixed field, as its name implies, it will only see out to a fixed distance.

What that gives us is the ability to ignore backgrounds.

In real-world applications, in factories, you may need to detect a target, but there may be a shiny bracket or a shiny wall directly behind it.

Fixed field sensors can ignore that object directly behind it.

And similar to that, we have adjustable field. So now the distance isn't fixed.

It's adjustable. We can move it in and out. And obviously that gives us some other advantages.

So that pretty much wraps up the modes, Scott.

So depending upon if you have a clean environment, a dirty environment, whether or not you just need to know if something is there or not.

Or maybe perhaps have to figure out if that's at a specific distance away from the sensor.

That's really going to help us determine what mode that we're gonna want to sense in.

In this module, we're going to take a specific close look at opposed mode sensing and some of the nuances that go along with it.

Darryl, can you walk us through opposed mode sensing pairs? Sure.

Thanks, Scott. So opposed mode, as we mentioned earlier.

You have an emitter in its own housing and a receiver in its own housing.

When an object comes in between those two, it fires the receiver's output, letting you know that there is a target present.

Now, one thing to keep in mind when you're using opposed mode, because they can see so far out to 700 feet, you have to keep power in mind.

Both of those sensors are going to have to be powered. But one of the nice things about apposed mode is it offers the highest amount of excess gain.

And we use these in applications where there is a lot of dust and/or debris.

So let's just take a carwash, for example. A lot of heavy wash going down, steam, mist, foam.

Opposed modes are able to see through all of that and detect the car very, very reliably.

Another quick application is looking at a box on a conveyor.

You must want to make sure that those boxes are there. Opposed mode does that very efficiently.

And again, we're using red LEDs, infrared, LEDs for high power, and laser for precision.

And again, we're pulsing those outputs. Now, one other thing to keep in mind is the output mode.

We have light operate and dark operate. Just to get the concept across.

If we have an emitter looking at a receiver, there's nothing blocking it.

And the sensor was in the light operate mode. That means the sensor's output will operate because there's nothing blocking the light.

If we converse, we had a dark operate sensor.

The output only operates in a dark mode, meaning that there is an object in between the emitter and the receiver.

Pretty much wrapped that up, Scott. So, Darryl, very basic application for photoelectric sensors would be a box coming down a conveyor.

So between light operate and dark operate, if I wanted the output of the sensor to turn on when it blocked the beam of the emitter and receiver, which one would that be?

So that would be dark operate because again, the object would be blocking the light from the emitter from receiving, from being picked up by the receiver.

So what if I wanted to see the gap between the boxes?

Then that would be light operate. Because now there's nothing obstructing the light from the emitter to the receiver.

Excellent. Thanks, Darryl.

Excess gain is a term that you'll run into when you're looking at a photoelectric.

We need to know how much power we might potentially have. Darryl, can you talk us a little bit through why excess gain is important.

Especially when we're selecting out some photoelectrics to use in an application?

Sure. Scott, thanks. As Scott mentioned, excess gain is the amount of light energy a sensor gives off.

That's very important. More is better. You always want as much as you can have for each application.

And again, that's why we always start off with the opposed mode. To show the amount of excess gain a sensor has, we have an excess gain chart.

This is a logarithmic logarithmic, or log log, for short chart that shows you the excess gain.

So real quickly, I can look at this chart and see that at one, which is the amount of light a sensor needs to turn on.

An excess gain of one will turn on the sensor's output.

So in this chart that we're looking at: out at 20 meters, we have an excess gain of one.

Now, that means the sensor can see a target, but barely.

That's equivalent to you and I go into the eye doctor and they say: hey, what's the smallest chart you can read?

You may be able to read that chart, but just barely. That's how a sensor sees a target at one excess gain.

So you never really want to operate there. We typically say if you're in a factory environment or warehouse, you want to be about five excess gain.

If you're in a slightly dirty environment, 10. If you're in a very, very dirty environment, you might want to be at 50 excess gain.

So here's an example of how we would use this excess gain chart.

So let's just say we're in a factory and we know that dust is going to build up on the sensor.

So even though this sensor can see out to 20 meters, we may not want to operate out that far.

To have an excess gain of five, we really on it want to be about 10 meters. Right.

So and again, excess gain, as its name implies, is the amount of light over what is needed to turn on.

Only one is needed to turn on. But you don't always want to operate there.

So if we're in a slightly dirtier application, you may want an excess gain of 10.

Again, the sensor can see out the 20 meters, but you may only want to be at six or seven to make sure that you're seeing through the dust and debris.

If you're in a very dirty environment, you may want to be at 50.

And here we're showing you if that's the case, you don't want to be any further than three meters back.

So that pretty much wraps up excess gain, Scott. So, Darryl, excess gain is the amount of power that we require to make the application work.

Why wouldn't we just use the highest amount of excess gain we can possibly find in every application?

Because there's some applications that you wouldn't want to use it in.

For example, clear or translucent material, because there's so much optical energy, it may just see right through it.

An example of that there, Darryl, is some of our highest power and highest excess gain products in our QS30 family.

You can see I can pass my hand right through these and that will not transition.

The output takes two hands in order for it so that the power that is contained in this opposed mode sensor, it's burning right through my hand.

So there may be opportunities for the sensor to actually blow through the product that you're looking at.

That's why that excess gain chart is so important in every application.

Going to go into a module now on two other terms as they relate to photoelectric sensors: beam pattern and effective beam.

Darryl, why are those two things so important when we're selecting a photoelectric to put into an application?

That's a great question, Scott. So we'll start off with the beam pattern.

The beam pattern is the radiation pattern, or it shows how the light emits from the emitter, how it spreads out.

The reason that's important is because in the real world, a lot of our sensors are mounted on a conveyor belt, for example.

So they need to be mounted next to each other as they're tracking products down a conveyor.

Well, you need to know how wide that beam pattern is so that the adjacent sensor is not cross talking with the other sensor.

That becomes very important. So we published this in our data sheet.

And as this example shows that we're looking at.

At the widest point, so the zero point, is the emitter, it shows how the light spans out.

And you'll see that the light is at its widest point from zero, goes up twenty five inches and down twenty five inches.

So there's a total of 50 inches of spread.

So what that tells you is: the sensor that you're gonna have next to the other sensor can not be any closer than 50 inches center to center.

And here's an example. This is another visual showing you that anywhere within that beam spread pattern, a receiver will pick up that light.

Again, this is just another example showing that that is a total of 50 inches of light spread.

Another important terminology is effective beam. So, it's different from the beam pattern.

The effective beam stays the same and it never changes.

This is the part of the beam that needs to be changed in order for the sensor's output to switch.

So what we say is good engineering practices. You want to block 100 percent of the receivers lens in order to ensure that the output will switch.

And this example we're showing emitter-receiver where there's an object, there's a pin there, but it's not blocking 100 percent of the light.

So even though there's a target there, the receiver never knows that and it never switches his output.

So we publish this information in our data sheet. And this example, we're showing that the effective beam is 13 millimeters or half an inch.

That's saying that your target, that's going to come in between the emitter and receiver has to be at least 13 millimeters or larger to be detected.

So wrapping up the opposed mode, we're going to hit on the advantages and disadvantages.

The advantage, again, is that it's high gain. That gives us extremely long range.

And it doesn't really care about color at all. The disadvantage is there can be so much power that it can burn through a clear or translucent object.

And it's hard to see small objects unless you're using something like an aperture.

And we can talk about that in more detail later. And you have to supply power for both sensors.

So that's pretty much wraps it up, Scott.

Darryl, you keyed in on a word there that makes my ears ring when you're dealing with photoelectrics and that's the word crosstalk.

That can be a very painful point when dealing with opposed mode photoelectrics.

What is one of your suggestions for trying to help us eliminate some of those crosstalk issues we may run into?

That's a great question and it does come up a lot. So I kind of briefly mentioned apertures.

So what an aperture does is: it actually goes over the lens element of a receiver and/or an emitter.

And it restricts the light pattern and it restricts the effective beam.

So that's one way of making that beam radiation pattern and effective beam much smaller, helping you to eliminate crosstalk.

Excellent. Thanks a lot, Darryl.

Retro reflective mode sensing offers a lot of advantages and flexibility when it relates to applications where you want to apply a photoelectric.

Darryl, can we touch a little bit on where we might use retro reflective and some of the nuances that go along with maybe applying a solution that uses a retro reflective photo eye?

Sure, Scott. So with the retro reflective mode, we have three different types.

Standard, polarized and coaxial. So I'll step through those with you.

Again, retro has the emitter and receiver in one housing and we have a separate reflector that sends light back to the receiver.

Object comes in between those, switches the sensor's output.

We use red light, which is helpful sometimes because you can go out to 30 feet or further with retro.

And it helps with alignment. We can also use infrared lasers becoming very, very popular.

And there's also polarized and on-axis and I'll get back to that later.

But out of those three different types of retro reflective sensors, the standard has the longest range.

Now, there's a "got you" with that, though. If you have an application that has a shiny object, let's just say you had a food plant and a shiny can is going down a conveyor line. That shiny can can mimic a reflector and send back a false trip.

So to get around that, we can go to polarize.

But before we do that, let's talk about the outputs on these. Again, just like opposed mode, we had light operate and dark operate.

Just a quick recap. Light operate means the emitter is sending light to the receiver.

If there's nothing blocking it, that's sensor's output will operate. Dark operate is the opposite.

If there is an object in between the emitter and the receiver, the output operates.

It is typically the mode that most people use with retro reflective sensors.

So, polarization: this is used to help safeguard against false proxing. And the way we do that is: we put a filter on the emitter and the receiver, 90 degrees out of phase with each other.

So let me give an example. In this example, on the emitter, we have the filter sending light out on the vertical plane.

It hits an object other than a reflector. Let's just say a shiny can.

The light will come back on that same plane. On the receiver, we have a horizontal lens so the light will not enter.

Therefore, guarding against false proxing. When you do the same thing with the reflector, light goes out on the vertical plane.

The reflector actually disorients the light. Light that comes back on the horizontal plane enters the receiver and we get detection.

Now, there's a drawback with this. Because of the filters, you have less excess gain and thus less range, but no false proxing.

And with all retro reflective sensors, you have a blind spot.

The reason for that is: as the light leaves the emitter and hits the corner cube in a reflector, the corner cube tries to send it back on the same plane.

However, it does fan out over time. There has to be a little bit of a distance between the sensor and the reflector.

That may be a disadvantage depending on the application.

Another important part is effective beam. So in this case, the effective beam becomes now the size of the reflector.

So if you have an application where you're trying to see a small object, let's just say a pin.

It will not block the entire reflector. Therefore, the sensor may never, ever see that pin.

So to get around that, you have to go with a smaller reflector. But keep in mind, smaller reflector, smaller surface area, shorter range.

Lastly is the coaxial. Up into this point, every sensor, every emitter has its own lens. Likewise, the receiver.

With coaxial, they share the same lens using a beam splitter and filters.

So the light hits the beam splitter, reflects to the reflector, comes back.

Part of that beam splitter sends light to the receiver. What this does for us, it gives us a lot of advantages.

We no longer have a blind spot. And with this technology, we can see a clear object.

So wrapping it up, the pros: again, retro reflective offers the second highest load of excess gain.

You only have to power up one site. There's no blind spot if you use a coaxial sensor.

This also gives you a very tight beam to see through small openings or for precise lead edge detection.

And we can detect clear objects. That pretty much does it, Scott.

Darryl, what you had talked about for reflector, you pretty much referred to a hard corner cube reflector like this guy here.

Another option in that area is reflective tape. It's very flexible.

You can trim it. You can cut it down, peel off the back, stick it to a rail.

So it's very flexible in that regard.

But what are some examples of where you wouldn't want to use reflective tape and maybe some of the drawbacks as a result of that?

Yeah. Great question. Because tape is very popular with a lot of customers, although it may not be advantageous.

Because, the main reason is: with every reflector, there are corner cubes.

And that's what sends light back to the sensor.

With tape, there are different types of corner cubes. They're not as efficient as a hard case reflector.

So you're going to lose a lot of range when you go to reflective tape.

It could also be problematic when you're using a polarized sensor because the corner cubes and tape don't quite rotate the light the same way a hard case reflector does.

Now, Banner does carry a special tape for that. You can call one of our application engineers and they can help customers out with it.

So while tape is a very flexible option, sometimes a hard case reflector is a better, more reliable solution in those retro reflective applications.

While tape may be reserved for more of those conquered bank style applications.

Photoelectric sensing proximity mode encompasses a lot of different application solutions in it,

Whether you're just trying to look for presence or absence of a target or if you're trying to determine a distance and maybe ignore some background.

Darryl, can you walk us through the different options as it refers to proximity mode in some of the different things that we should look out for when we're putting a photo eye into those applications?

Sure, Scott. So we're going to start off with the diffuse mode. Diffuse mode sensor has the emitter and receiver in one housing.

Now, this time it doesn't need anything like a reflector or receiver on the other side.

Diffuse spreads light out. And the object that it is trying to detect is what sends light back to the element.

And again, with these sensors, we use red LEDs, infrared and laser.

One thing you need to be aware of when you're using a diffuse sensor.

All of our sensors have a spec range that is based off of a target that sends back 90 percent of the light that hits it.

In the real world, that won't always be the case. So even though a sensor may have a spec range, let's just say, of three feet.

If it sees a target that is dark, it may only detect that target out to one feet.

That is a universal issue with all diffuse sensors. And it's just something to be aware of.

Also, there's no cut off distance with diffuse sensors.

So if you need to detect a box on a conveyor, but there's a shiny object behind it, it may see the box and the shiny object.

But the advantages of diffuse is, they're very low cost and work great in very simple type applications.

Now, there is a way to get around this background issue. We have a variation of diffuse.

Up onto now, every sensor had one emitter and one receiver.

What we've done with our fixed field sensors is we have one emitter, two receivers.

That second receiver gives us cut off because we are using it with triangulation.

So in this example, you see the light emits from the emitter, hits a target.

The closer that target is, the greater the attack angle is and it hits receiver one.

As long as light is hitting receiver one, it keeps the output on.

But you notice as that target backs up, the angle changes to eventually it hits receiver two. Any light that hits receiver two turns the output off.

So in this case, when we have a fixed range, we know exactly where that range ends.

So you can have a shiny bracket behind a target and a fixed field sensor will ignore that. So a huge advantage.

That's just another example of hitting receiver two.

We also have adjustable field, and these are no longer fix, they are adjustable.

So you can dial it in to the range that you need and continue to get background suppression.

Another great advantage.

So, some of the advantages of, again, using diffuse and fixed field: you only have to power up one side; lowers your installation costs.

It can detect objects out to a set distance. It ignores objects in the background that you don't want to see.

And color also is really not an issue with background and adjustable field sensors.

In proximity mode, Darryl, would that be...which of those modes would be best for an application where maybe you would have to pick up a registration mark on a product that's going by?

So with that one, depending on the application, fixed field might be really, really good.

Because you may have something in the background that you won't ignore when that registration mark is gone.

Or adjustable field, because that gives you the ability to dial it in even more precisely as to where you need to cut off to be. OK.

And then light operate and dark operate as it relates to proximity mode.

If we want to transition the output ON when the target is in front of us, which mode would we be looking at?

So this mode would be light operate. And the reason is, as light leaves this emitter, the target that it is looking for sends light back.

So when the sensor sees its light, it turns on its output.

So dark operate then would be for no target present, correct?

Exactly. All right. Thanks a lot, Darryl.

Fiber optic sensors provide a unique way and a bunch more flexibility in applications that extend beyond just simple photoelectric sensors.

Darryl, can you walk us through some of the basic elements of where and when we would use some fiber optic sensors in applications?

Sure, Scott. Great question. Yeah. Sometimes fiber optics is the only option, depending on the environment.

As you see here, we have a lot of photoelectric sensors, but some of them may not be small enough to get into a very tight, small, confined area.

That's where fiber optics shine.

So the way they work is you have a fiber optic amplifier and you have either a glass or plastic fiber that attaches to it.

The fiber sends the light out to the inspection area and back to the amplifier.

Now, there are a lot of advantages with that. Again, you can see a small area.

And earlier I mentioned that we have a fiber amplifier that has a response speed of 10 microseconds.

That is in this family, our fiber optic family.

But another great advantage is because fibers have no electronics, they can go into very electrical noisy environments, chemical environments,

And sometimes they can go even into hazardous environments where there's hazardous gases, where you don't want any electronics because of explosions.

So there is a lot of advantages there. So here's a little bit closer look at glass and plastic.

Why would you use glass? Glass can go up to nine hundred degrees Fahrenheit.

And because it's glass and stainless steel, there's a lot of chemicals that it can withstand.

The disadvantages: you can't really flex it too much because it is glass. So therefore, you can get breakage.

The plastic is a little bit smaller, so typically doesn't go as far as glass.

Although we do now have high powered amplifiers that get that range back to you because they're so high powered.

And you can also put a stainless steel sheeting on the plastic fiber as well.

And they're extremely flexible. So that pretty much wraps it up, Scott.

So, if we had an application Darryl, maybe something like a pick and place machine.

Maybe our robotic end effector, that's going to be moving around a lot.

Would we want to go with a glass fiber, something like the stainless steel sheathing fiber or something a little bit smaller, like a plastic?

And why would we want to go one direction versus the other? That's a great question.

So plastic fiber would be the short answer. OK.

And the reason being, as you can see, it is pretty flexible. So this allows the robot arm to flex quite a bit without any breakage.

This is one solid plastic core inside. So there's really nothing to break versus the glass fiber that has a lot of multiple strands of glass.

Continually flexing would break that and eventually it would fail in the application.

So plastic would be the way to go in those high flex applications. Absolutely.

All right. Thanks a lot, Darryl. The goal in any photoelectric sensing application is to provide an output to an external controller.

But even those output types can be a little confusing and there's a lot of things to consider on that front.

Darryl, can you walk through a little bit on the output styles that we can get from photoelectric sensors and where we might use those?

Be happy to. So when it comes to discrete outputs, you have two options, PNP sourcing or NPN sinking.

I'll start off with PNP. So as its name implies: sourcing, you are sourcing a voltage.

So in the image that we're looking at here, you'll notice that we have power to the sensor.

Plus is on pin one, ground is on pin three. And if you follow the line here, pins four and two are your output.

In this normally closed contact configuration, we are sending plus Volt to the load.

Now, that load could be a PLC, could be an HMI. It could be a relay.

It could be a number of different items. On the other side of that load, it must go back to ground to complete the current path.

And so which one would you use? How do you know when you use PNP or an NPN?

And that's going to be determined by the PLC.

For example, if you're using a PLC, it will be determined by the card if it wants to see a sourcing or a sinking input.

So NPN is doing the opposite of sourcing; it is sinking. So in this example, if you look at pin three, we have DC ground.

So you follow the trail again to pin two where the load is.

We're going to send a sinking input. On the other side of that load is plus Volts. Again, completing the current path to turn on the output.

There's another option. We have several sensors that have relay outputs.

When would you want to use that? In some cases? You want to switch AC power.

And what's nice about a relay is you can switch AC or DC.

So in this case, we could power this sensor up because this is universal power; it can be powered up by AC or DC.

You can power the sensor up by a DC power and switch AC power.

That's a big advantage depending on what your output needs to power up. So Darryl, NPN, PNP, those are solid state style outputs, correct?

Correct. And our really interface that you're showing right now.

That's obviously a mechanical dry contact.

What's the disadvantage of having a really output versus one of those solid-state outputs on the NPN or PNP?

Well, you know, we talked earlier about response speed. And our sensors are extremely fast, down to 10 microseconds.

You won't get that kind of response speed with a relay. They're a lot slower.

They can switch a lot at current. A lot of Amps. But the disadvantage is they're slower, typically around 20 milliseconds.

So if you have a high speed application, it probably won't work for you. How about longevity?

Yeah, that too, because it's mechanical. There's only so much ON and OFF actuation that these contacts can take.

Eventually they're going to wear out. But we do specify that in our data sheets. Excellent.

All right. Well, we want to thank you for sitting through and watching our modules on photoelectric sensing.

The basics, as it relates to opposed mode, retro reflective mode, proximity mode and the output styles that go along with it.

For Darryl Harrell, I'm Scott Behnke. Thanks a lot.