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In this video,
I will be talking about laser sensors.
I will explain what laser sensors are,
the basics of how they work,
the different types of laser sensors,
and I will give some examples of
how laser sensors are used with automation.
A laser sensor is an electric device
that uses a focused light beam to detect the presence,
absence, or distance of an object.
The light that a laser sensor emits is a small bright dot,
similar to a laser pointer.
This dot is bright enough to be easily seen even in direct sunlight.
And being able to see this dot easily,
makes it easier to set up and troubleshoot the laser sensor.
On some laser sensors,
the light can be turned off when the sensor is not being used.
Now let’s talk about how the laser sensor works.
First, the light travels from the sensor to the object.
The light then bounces off the object back to the sensor.
The sensor then calculates how long it took
for the light to travel to and from the object
to determine the distance.
If the object was within the sensor's range,
the output of the sensor will turn on.
If the object was not in the sensor's range
the output will stay off.
To set up when the laser sensor output turns on
depends on what type of laser sensor you have.
If it is just a basic laser sensor,
you just turn a dial or a ring on the laser sensor
to adjust it from its minimum setting to
its maximum setting.
Other laser sensors have a display and buttons on them
that are used to configure the sensor’s min and max settings.
And other laser sensors require a computer to be connected to them
to configure the min and max settings.
Depending on what laser sensor you have,
the sensor outputs can be normally open,
normally closed,
NPN, PNP, or analog.
Also depending on the laser sensor,
the analog outputs can be zero to ten volts
or four to twenty milliamps.
Typically if you are using the sensor’s analog output,
the sensor is connected to a PLC analog input card.
An example of when a laser sensor analog output might get used
is to check the position of a part before it enters a robot cell.
The sensor’s analog signal is read by the PLC
and the PLC displays this number on an HMI screen,
along with the range that is considered good.
If the part is in the correct position,
it will get released into the robot cell automatically.
But if the part is out of position,
an alarm will sound
and the part will not release until the part is in the correct position
and the reset button on the HMI is pressed.
This is an example of when a laser sensor
would be used to check distance.
Now let’s talk about some of the reasons why you would use a laser sensor.
They work very well in dusty conditions.
The brighter light of a laser sensor has fewer issues in dusty environments
compared to other styles of sensors.
The bright light of the laser sensor
is not affected by other light sources.
Laser sensors can even be used in direct sunlight.
With the size of the laser sensor light dot,
it works great at detecting small objects.
Laser sensors can also be used for precise positioning.
Laser sensors can also have a very long working range if needed.
A lot of the laser sensors made today
use twenty-four volt DC power.
To use one of these sensors,
connect the brown wire to twenty-four volt DC positive.
Connect the blue wire to twenty-four volt DC negative.
The black and white wires are the sensor’s output wires.
And depending on your needs
one or both of these wires
will get connected to a PLC input card.
With these wires connected
the sensor is ready to be set up.
Let’s say we have a conveyor
and they want to load boxes to be shipped out on one side
and have these boxes travel to the other end of the conveyor
and stop so the box can be removed by an operator.
So we mount and wire a basic laser sensor on the end of the conveyor
where the box needs to stop.
To set up the laser sensor,
we set a box on the conveyor
where we would like it to stop.
We will then aim the sensor at the leading edge of the box
and tighten it down.
With this being a basic laser sensor,
we just turn the dial on the sensor
until the output light on the sensor turns on.
To test the sensor that we set up,
we remove the box and turn on the conveyor.
We then place the box on the running conveyor
and see if the box stops where we wanted it to.
For another example,
let’s say we have a part that gets loaded onto a build pallet.
Before the pallet can leave this station,
a laser sensor needs to see that a pin has been installed
to keep the part from falling off the build pallet.
We are using a laser sensor
because the pin is not very big
and a laser sensor can be mounted
so that it is not in the way of the operator.
In review, by watching this video
you have learned about laser sensors.
That they use a focused light beam to detect the presence,
absence, or distance of an object.
You also learned that laser sensors
are a better choice for dusty or bright light environments
and that they can be used on small objects
and can have a long working range.
That should do it for this video.
Please let us know if you have any questions about laser sensors
in the comments below.
Also, make sure to like this video if you found it helpful.
This will help other Automation Engineers like you,
find this video.
Thanks for watching!
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