How to determine if a proximity switch is normally closed or normally open with a multimeter
1, three-wire DC24V inductive PNP type: brown to +24V, blue to 0V.
Black DC voltage digital multimeter connected to the red pen, black pen connected to 0V.
At this time the multimeter has 24V voltage is normally closed, no 24 volts is normally open.
2, three-wire DC24V inductive NPN type: brown to +24V, blue to 0V.
Black DC voltage digital multimeter connected to the black pen, red pen connected to +24V.
At this time the multimeter has 24V voltage is normally closed, no 24 volts is normally open!
Multimeter how to detect the button normally open and normally closed point what phenomenon
When using the multimeter to check the normally open and normally closed points, the multimeter should be adjusted to a voltmeter first, check whether there is voltage in the line accessing the contacts, and then check the normally open and normally closed contacts.
1. connect the two pens of the voltmeter to the two ends of the normally open point, if there is no voltage, the multimeter will be adjusted to the ohm file, the two pens are connected to the two ends of the contact, the multimeter is displayed as 0, it is a normally open contact, and if there is a data of the multimeter, it is about 0.1-1Ω, it is a normally closed contact.
2. If there is a voltage, it can be concluded that the contacts for the normally open point, at this time it is also prohibited to adjust the ohm gear to check, because adjusting the ohm gear, the two pens access, the multimeter is equivalent to a wire, which is equivalent to the normally open point of a short-circuit, so that the normally open into a normally closed, which may burn out the multimeter, and even on-site devices that line conduction, resulting in inestimable dangers!
How to measure the photoelectric switch normally open
1, single contact can be distinguished from the model parameters.
2, many products at the same time to provide normally open and normally closed two groups of contacts, you can see the logo on the switch
3, you can use a multimeter to measure
