How to convert signal NPN (Positive common) to PNP (Negative common)

The proximity switch sensor is generally a switch to disconnect the positive signal DC voltage to the PLC. However, if the PLC input used is common negative, then the sensor used is the NPN type, because this sensor will work well to break the negative relationship with the trigger base is positive.

For example, if we experience a failure from a PNP sensor and do not have spare parts of the same type, sometimes the signal conversion trick can be used. This is very easy to do if we know the working principle of both PNP and NPN type sensors. From the description above, to change the sensor output signal which breaks the positive relationship (PNP), we need an NPN type resistor and transistor, for example the TIP31C (capable of passing about 2 amperes more).

Here I will provide a simple circuit to convert the signal from an NPN type to PNP sensor with a TIP32C transistor and a 1K resistor. The sensor used previously was the SICK sensor with no. series WL9-3P2232 (PNP), because I didn't get it, I replaced it with the NPN type, but it had to be converted in order to break the positive relationship. Here's the series: