Identification of photoelectric switch wiring

Identification of photoelectric switch wiring:
BK (black): generally, it is an output line, and the output is normally open.
BN (brown): it is generally a power line, connected to the positive pole of the power supply.
Bu (blue): it is generally a power line, connected to the negative pole of the power supply.
Wh (white): it is generally an output line, and the output is normally closed.
NPN: the black end is connected to the load, and the other end of the load is connected to the positive pole of the power supply.
PNP: the black end is connected to the load, and the other end of the load is connected to the negative pole of the power supply.

The load can be the signal of PLC, relay coil or digital input module.