RDC6332M, when it can follow up, press the auto focus button, the laser head starts to descend, touches the iron plate, and then rises to the reference focus position, and then stops, without lifting

Cause analysis:
Whether the upper and lower limit are enabled and whether the upper and lower limit switches are touched.

How to solve:
Change the limit enabling to No, press the auto focus button to check whether it is normal. If the auto focus is normal, it is the upper and lower limit switches that are touched, and the limit polarity is reversed.