How to Measure the Normally Open and Normally Closed Points of a Photoelectric Switch with a Multimeter
How to distinguish whether a photoelectric switch is normally open or normally closed
Photoelectric switch (photoelectric sensor) is the abbreviation of photoelectric proximity switch. It uses the obstruction or reflection of the detected object on the beam of light, and the synchronous circuit selects the circuit to detect the presence or absence of the object. Objects are not limited to metals, and all objects that can reflect light can be detected. The photoelectric switch converts the input current into an optical signal on the transmitter and emits it. The receiver then detects the target object based on the strength or presence of the received light. The common photoelectric switch smoke alarm in security systems is often used in industry to count the number of movements of the robotic arm.
Nowadays, many optoelectronic switches have both normally open and normally closed outputs. Normally open and normally closed are the output states of a photoelectric switch when no object is sensed. The meaning is that the photoelectric switch has a normally open output and a normally closed output when there is no action.
Distinguishing whether photoelectric switches are normally open or normally closed: 1. Single contact switches can be distinguished from model parameters; 2. Many products offer both normally open and normally closed sets of contacts, which can be seen from the identification on the switch; 3. A multimeter can be used for measurement
How to Use a Multimeter to Determine whether a Proximity Switch is Normally Closed or Normally Open
Is the proximity switch normally closed or normally open?
1. Inductive PNP type with three wire DC24V: brown connected to+24V, blue connected to 0V,. The black lead is connected to the red lead of the DC voltage range of the digital multimeter, and the black lead is connected to 0V.
At this point, the multimeter has a 24V voltage that is normally closed, and no 24V voltage that is normally open.
2. Inductive NPN type with three wire DC24V: brown connected to+24V, blue connected to 0V,. Connect the black lead to the DC voltage range of the digital multimeter, and the red lead to+24V. At this point, the multimeter has a 24V voltage that is normally closed, and no 24V voltage that is normally open
