What is the function of touch reset on yarn sensor

Touch reset is mainly for closing yarn cutter. When there is no yarn, we need some seconds for putting yarn on the machine, so we need touch reset to hold yarn cutter. When the light of touch reset is off, yarn sensor will give signal to yarn cutter nornally.

How is Sensors working with PNP output?

PNP is positive ouput, it is normally open. When yarn works well, sensors LED light is off. When yarn broke or out of yarn, sensors LED light is on.  

How is Sensors working with NPN output?

NPN is negative ouput, it is normally closed. When yarn works well, sensors LED light is on. When yarn broke or out of yarn, sensors LED light is off.