Proximity sensors play an integral role in the automation of industrial production. Today we will discuss how to choose the right proximity sensor, what are the elements of picking a proximity sensor, and how to check and inspect proximity sensors.

Selection of proximity sensors:
Different types of proximity sensors should be selected for different materials of detectors and detection distances in order to obtain a cost-effective system. For this reason, the following principles should be followed in the selection:
1, when the detection body for the metal, should use a high-frequency oscillation type proximity sensor, the most sensitive to the detection of iron-nickel and A3 steel. Aluminum, brass, and stainless steel detector body detection sensitivity is lower.
2, when the detector body is made of non-metallic materials, such as wood, paper, plastic, glass, or water, capacitive proximity sensors should be used.
3. Photoelectric proximity sensors or ultrasonic proximity sensors should be used for long-distance detection and control of metal bodies and non-metals.
4. Low-cost magnetic proximity sensors or Hall-type proximity sensors can be used when the detector body is metal but the sensitivity requirement is not high.

Elements of proximity sensor selection:
① Detection type: built-in amplifier, separated amplifier;
② Shape: round, square, slot;
③ Detection distance: mm;
Detection object: iron, steel, copper, aluminum, plastic, water, paper, etc. ⑤ Operating power: DC, AC, AC/DC universal;
⑤ Working power supply: DC, AC, AC/DC universal;
⑥ Output form: normally open (NO), normally closed (NC);
(vii) Output mode: two-wire, three-wire (NPN, PNP);
⑧ shielded and unshielded;
⑨ Output type, connector type, connector relay type;
⑩ Response frequency: one second to detect multiple objects

Proximity sensor detection:
Determination of release distance: When the action piece leaves the sensing surface of the proximity sensor from the front and the switch changes from action to release, measure the maximum distance of the action piece from the sensing surface.
Determination of hysteresis H: Absolute value of the difference between the maximum action distance and the release distance.
Measurement of action frequency: Drive a Bakelite disk with a speed-regulated motor, place several steel chips on the disk, adjust the distance between the detection surface of the switch and the action chip to about 80% of the action distance of the switch, rotate the disk, and perform the action sequentially. The chip is close to the proximity sensor, and the disc spindle has a speed measurement device to form a switching output signal connected to a digital frequency meter. At this point, start the motor and gradually increase the speed. If the product of the speed and the action chip is equal to the frequency count, the frequency meter can directly read out the operating frequency of the switch.
To repeat the accuracy measurement, mount the action piece on a measuring tool and approach the switch action area from the front side of the switch sensing surface more than 120% of the switch action distance while maintaining a travel speed of 0.1 mm/s. After activating the switch, take a reading on the measuring tool to turn off the switch before exiting the operating area. Repeat this process 10 times and then calculate the difference between the maximum and minimum of the 10 measurements and the average of the 10; the greater the difference, the greater the repeatability error.