I. Proximity switch outlet classification:
2-wire type is divided into three kinds: DC 2-wire type, AC 2-wire type, and AC/DC dual-use 2-wire type.
3-wire type only DC 3-wire type, it has NPN and PNP two kinds of output form. NPN way in the Asia-Pacific region to use more; PNP way in the European region to use more
Second, the proximity switch wiring difference
Difference 1: 2-wire wiring is relatively simple, two wires for the power supply and power supply, respectively, the signal line and the power line shared, so the circuit must be allowed to take the current of the load after the current can be connected to the power supply, do not allow unloaded power supply.
3-wire type, there are two lines were the power supply and power supply negative, the other is the signal line, NPN output load connected to the power supply and signal line between the positive, PNP output load connected to the power supply and signal line between the negative.
Difference 2: When using a 2-wire sensor, the output circuit of the residual voltage, leakage current is larger (even when the sensor is OFF, the leakage current in the circuit will lead to false operation), so we must make sure that the leakage current in the circuit is less than the load reset current.
3-wire circuit in the residual voltage is small, more reliable, anti-interference ability is stronger, in some of the use of higher requirements of the occasion, in order to avoid generating false action, you can choose 3-wire sensors
Third, how to choose to apply their own way out of the line
2-wire type than 3-wire leakage current, anti-interference performance is not as good as 3-wire type, so in the measurement of high precision requirements of the occasion, you can choose 3-wire type. If the measurement accuracy is not high, in order to facilitate the installation and maintenance, then you can choose 2-wire type.
