ELECTRONICS FOR FIBER OPTIC VORTEX SHEDDING FLOWMETER

摘要

ELECTRONICS FOR FIBER OPTIC VORTEX SHEDDING FLOW METER An optical sensor arrangement comprises a light-emitting diode which is connected to a light detector over a light connection such as a fiber optics fiber. The fiber may be provided in the vicinity of a vortex shedding flow meter and is bent by the passage of vortices past the fiber. Bending the fiber causes attenuation of the light signal from the light-emitting diode to the light detector. The light-emitting diode is powered by a pulse generator which supplies the diode with low duty cycle high-current pulses. The resulting detected pulses are amplified, sampled and held to obtain peak values for each pulse. The detected pulse is suppressed by a feedback circuit portion which is activated only after each low duty cycle high current pulse. The detected peaks are utilized to generate a square wave which is used as a measurement of the variable, in particular the passage of vortices in a vortex shedding flow meter.