Electro-Sensors' ST420 Shaft Tachometer

Electro-SensorsInc. announces the ST420, a loop-powered,stainless-steel analog shaft tachometer. The ST420 requires no usercalibration, providing a dependable shaft speed monitoring solution right outof the box. Only 18 mm in diameter, it reliably detects magnetic pulses from arotating shaft-mounted pulser disc or wrap. Then, the ST420 uses quartzcrystal-based digital processing to convert pulses to a smooth, continuous4-20mA analog signal directly proportional to the pulse frequency. The resultis a plug-and-play solution that allows users to accurately and simply monitorrotating shaft speed in industrial applications.

TheST420 shaft tachometer has been tested by UL to the standards UL913 and CAN/CSAC22.2 No 157-92 (Intrinsic Safety), assuring it provides an intrinsically safesolution for Class I (Groups C & D) and Class II (Groups E, F & G)environments, when used with an approved I.S. barrier. Its magnetic pulsedetector, signal processing capability and 2-wire loop-powered 4-20 mAcircuitry are combined into a stainless-steel M18x1 sensor housing. The ST420resists harsh plant environments and is rated NEMA 4X/IP67.

Offeringboth standard and custom measurement ranges, the ST420 facilitates preciseshaft speed monitoring in industries including:

Electro-Sensors' ST420 Shaft Tachometer_A