How to measure proximity switch with 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 understand what this proximity switch is.
Proximity switch, as the name suggests, is a switch that only works when "close". Proximity switches should be classified into position switches. The biggest difference from our common travel switches is that proximity switches can complete position measurement without touching the measurement object.
In short, the essence of a proximity switch is still a switch, but the working principle of this switch is different. The common proximity switches currently on the market can be roughly divided into the following categories:
Photoelectric proximity switch: Through the reflection of light, when there is an obstacle blocking the emitted light, the device will generate an on or off signal.
Hall proximity switch: You may not know much about the word Hall. In fact, Hall is a form of circuit. It is sensitive to magnetic substances. When a magnetic object is detected, a circuit that cannot function will generate changes, and then passes through the conversion circuit to output the corresponding on or off signal:
Capacitive proximity switch: Speaking of capacitive type, everyone needs to understand the issue of dielectric constant. When an object passes between the two plates of the capacitor, the dielectric constant will change, thus generating a signal, which then passes through the circuit. Convert for output.
After we power 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 to a triode. Relatedly, when the main circuit of the proximity switch senses an object, an on-off change will occur within the circuit, so that the two ends of the load in the figure below form a closed loop, that is, the 24V power supply is added to both sides of the load. This is actually The above is the working principle of the proximity switch.
When we use a multimeter to measure, 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 certain whether the load end and the power supply share the same positive pole or the common negative pole. Actual measurements must be made according to our product instructions.
