Reed switch Magnetic proximity switch sensor In the field with a hole punched in the iron plate to fix the sensor through the hole (next to the magnet but not to the sensing distance)

1, although the magnet is far away from the reed switch, if the magnet is close to the iron plate, the iron plate is magnetized as a whole, causing the reed switch to conduct.

2, the iron plate is magnetized by other magnetic tools during the punching process.

Solution:

1, keep the magnet away from the iron plate to prevent the iron plate from being magnetized.

2, after the drilling is completed, use the hammer to hit the vibration of the iron plate, can make the processing of residual magnetism disappear.