Digital RPM Tachometer Work with encoder/switch/other signals for measurement of RPM,HZ,line speed, ... digit display. Digital RPM Tacho meter/ Techometer (FA) Usage: Applications with control equipments for frequency / tacho / line-speed / flow measurement ... waveform pulse(square wave,triangle wave,proximity switch,photo switch or AC voltage)volt signal, contact switch, encoder, etc. Or power frequency( ...