This product adopts Hall sensor for speed measurement. Through the internal function of the program, one probe can be set for multiple detection points, thus improving the detection accuracy. The speed measurement adopts the multiperiod average speed measurement method, which has a wide range of low speed, high speed measurement and high measurement accuracy. The counting function is realized by the external counting function of the singlechip timer, which is stable and reliable. Features: This product is a multifunction speed measuringcounting meter with speed measuring function, counting function and upper limit alarm output function. With reliable performances, simple installation and wide application range, it is generally applicable to all kinds of mechanical equipment, such as harvesters, machine tools, motors, fans, etc., where rotational speed measurement is required for devices, as well as production counting and other occasions. This product is compatible with Hall switch, metal proximity switch, infrared proximity switch and other detection switch signals. This product can output a channel of NPN alarm signal, and the user can connect the indicator light and sounder for warning. The user can customize the alarm field values. The supporting sensor of this product is a threewire sensor, which uses electronic technology to make the sensor have high sensitivity, strong reliability, fine AntiInterference performance, stable operation in the long term, and can be used for speed measurement and counting functions. Specifications: Working voltage: DC924V Basic range: SingleDetection point speed range: 3080000 rpm Speed range=singlepoint rangenumber of detection points (minimum 10 rpm) Count: 19999 Error range: + 1percent , Refresh rate: more than 1 timesecond Display: 4bit 0.56inch Hole size: 76.5 * 39.5mm Working temperature: 0 to 60 celsius (relative humidity below 80percent ) Item size: 78 * 42 * 24mm 3.1 * 1.7 * 0.9in Package size: 130 * 80 * 45mm 5.1 * 3.1 * 1.8in Package weight: 100g 3.5ounce Packing List: 1 * Digital Tachometer Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.