Proximity Sensors

Mouhammad Hamsho
A free video tutorial from Mouhammad Hamsho
Engineer
4.7 instructor rating • 5 courses • 14,279 students

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From Wire to PLC , A Bootcamp In Industrial Automation

Build Electrical Automation Projects From Sctratch. Starting From Wires , Control Circuits And Ending With PLC And HMI

16:54:04 of on-demand video • Updated January 2021

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  • Learn to program PLC in Fucntional Blocks (FB)
  • Learn to program PLC in Structured Text (ST)
  • Learn to program PLC in Continuous Flow Chart (CFC)
  • Design Human User Interface (HMI)
  • Design protection for electrical panel
  • Learn about the different sensors exist in indusrty
English [Auto] Welcome, guys, in this lecture, and now we will be talking about proximity sensors or in more depth, we will be talking about capacitive and inductive sensors. Now, as the name states, proximity sensors will be activated when an object comes close to the sensor. Unlike the limited switches, proximity sensors, the objects shouldn't necessarily touch the sensor. In order to get the signal, we can work in the range of a few millimeters to a few tens of centimeters. And I'm sure that if you look at any factory that has machines, you will find one of these sensors fixed at some place in order to detect some product or an object. Moving now capacitive, an inductive sensor, especially the proximity. One might look really similar from the outside, however, from the inside and from a circuit point of view, there are totally different. The principle of operations totally different. So starting with capacitive sensors, they are used with any type of object, so you can just put any object in front of them and they will detect it if they are within a certain range that is usually adjustable through a small screw on the proximity sensor. And as I said, their range could be a few millimeters to a few tens of centimeter. And these sensors are digital type. So when an object is detected, you'll get an digital output of a rating of 24 volt DC, or in rare cases you might find it with a rate of twelvefold DC. Now, the inductive sensors there are only used to detect metallic objects. If you put a plastic object, a wooden object in front of it. It wasn't detected and it won't give you any output. They also operate on 24 volts or 12 of DC. Now, let's take an example for a capacitive sensor, let's assume that we have a conveyor ban and we have a plastic object moving up of it and the sensor is fixed above this conveyor belt. Now, when the sensor is not seeing the plastic object, the sensor goes off and it's generating 04. Once the sensor is directly looking at the plastic object, the sensor will output 24 volt DC and then we can take this signal and take some action, let's say, inside our p.l.c. program. Now, let's take an example for an inductive sensor. Let's say we have food products and food, the products are sensitive to metallic parts, so you cannot have metallic parts inside your milk, let's say. During your production, you never know where foreign parts might come in and interfere with your product. So you want to make sure that when this product goes to the customer, it does not have any falling apart. One of the methods to detect these parts is to check if there is a metallic parts inside this product. So what we do is we put this food product on a conveyor band and it goes under an inductive sensor, if this inductive sensor senses any metallic part, it's going to output a signal to our p.l.c. or program and say, OK, this product is a problematic ejected out of the system. So this is it for proximity sensors. Guys, see you in the next tutorial.