The signal output mode in the cooling fan can be divided intofour modes:FG RDH (usually referred to asRD), RDL (orRDb), and LD , which are explained separately as follows:

FG  is the abbreviation of  Frequncy Generator , frequency generator, used to detect fan speed

RDH (RD)     is the abbreviation of Rotation Detection , running status detection, stop high level alarm    

RDL (RDb) is the abbreviation of     Rotation Detection , running state detection, stop low level alarm   

LD   is the abbreviation of  Low Detection , the speed is lower than the limit value and output high level alarm

That is, above the cooling fan four kinds of channel number output!

The above information comes from Dongguan Yinhai Electronics Co., Ltd. ( www.yinhaidg.com ), an enterprise focusing on fan R&D and production . Please indicate the source for reprinting!