How to measure the proximity switch with a multimeter
Proximity switch can be measured by multimeter; Its measurement method is also very simple, just regard it as a switch.
So, let's find out what this proximity switch is.
Proximity switch, as its name implies, is a switch that "proximity" will work. The proximity switch should belong to the position switch. The biggest difference from our common travel switch is that the proximity switch can complete the position measurement without touching the measured object.
In short, the essence of proximity switch is 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 proximity switch: You may not know the word Hall so well. In fact, Hall is a form of circuit, which is sensitive to magnetic substances. When a magnetic object is detected, the circuit will change, and then the response on or off signal will be output through the conversion circuit:
Capacitive proximity switch: When it comes to capacitance, we should understand the problem of dielectric constant. When something passes between the two plates of the capacitor, the dielectric constant will change, thus generating a signal, which will be converted by the circuit and output.
How to measure the proximity switch with a multimeter?
Although it is also a switch, the measurement of this proximity switch is somewhat special. We can't measure anything directly, because this proximity switch needs power supply when it works normally, just like an electrical appliance, which needs to be connected with a power supply, and most of them are DC 24V.
When we supply power to the proximity switch, we still need to know about its internal wiring mode. Let's take the three-wire proximity switch as an example. It is not difficult for friends who know some circuit knowledge to see that the on-off of the proximity switch is related to a triode. When the main circuit of the proximity switch senses something, the on-off change in the circuit will occur, so that the two ends of the load in the figure below form a closed loop, that is, 24V power is added to both sides of the load, which is actually 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 proximity switches, it is not necessarily whether the load terminal and the power supply are common positive or negative, and the actual measurement should be carried out according to our product manual.
