How to measure the proximity switch with a multimeter
The proximity switch can be measured with a multimeter; the measurement method is also very simple, just treat it as a switch.
So, let's find out what this proximity switch is.
Proximity switch, as the name suggests, is a switch that works only when "close". The proximity switch should be attributed to the position switch. The biggest difference from our common travel switches is that the proximity switch can complete the position measurement without touching the measuring object.
In short, the essence of the proximity switch is still a switch, but the working principle of this switch is different. At present, the common proximity switches on the market are roughly divided into the following categories:
Photoelectric proximity switch: Through the reflection of light, when there is an obstacle blocking the radiated light, the device will generate an on or off signal.
Hall-type proximity switch: You may not be familiar with the word Hall. In fact, Hall is a form of circuit. It is sensitive to magnetic substances. When a magnetic object is detected, the circuit will generate Change, and then through the conversion circuit, output the corresponding on or off signal:
Capacitive proximity switch: When it comes to capacitive, everyone needs to understand a problem of dielectric constant. When an object passes between the two plates of the capacitor, the dielectric constant will change, thus generating a signal, and then passing through the circuit Transform for output.
How to use a multimeter to measure the proximity switch?
Although it is also a switch, the measurement of this proximity switch is a bit special. If we measure it directly, we will definitely not be able to measure anything, because this proximity switch needs power supply during normal operation, which is equivalent to an electrical appliance. It needs to be connected to a power supply, while most are DC 24V.
After we supply power to the proximity switch, we still need to understand its internal wiring method. Let's take the three-wire proximity switch as an example. Friends who know some circuit knowledge can easily see that the on-off of the proximity switch is connected with a triode. Related, when the main circuit of the proximity switch senses an object, there will be an on-off change inside the circuit, so that a closed circuit will be formed at both ends of the load in the figure below, that is, the 24V power supply is added to both sides of the load, which is actually The above is the working principle of the proximity switch.
When we measure with a multimeter, we can know whether the proximity switch is on or off by measuring the voltage on both sides of the load.
Please note here that because of the different forms of the proximity switch, it is not certain whether the load terminal and the power supply share the same positive or negative pole, and the actual measurement should be carried out according to our product manual.
