Multifunction speed measuring and counting meter with speed measurement function, counting function and upper limit alarm output function Reliable performance, simple installation and wide application range; generally applicable to all kinds of mechanical equipment such as harvesters, machine tools, motors, fans, etc., where rotational speed measurement and production counting are required Compatible with Hall switch, metal proximity switch, infrared proximity switch and other detection switch signals Outputs one channel of NPN alarm signal; users can connect indicator light and sounder for warning Use scenarios In a harvesting machine, monitor rotor speed and production count, and trigger an alarm when the upper limit is reached In machine tools or motors, monitor spindle or shaft speed and cycle counts, with warnings available via indicator and audible alert In fans or other equipment, track rotation speed and production counts for process control and preventive warning when limits are exceeded