TWO-WIRE TRANSMISSION SYSTEM FOR VORTEX FLOWMETER

摘要

1529907 Two-wire transmission system for flowmeter FISCHER & PORTER CO 3 Dec 1976 [9 March 1976] 50576/76 Heading G1U Low-frequency signals from Piezo-electric generators 12, 13, forming part of a vortex flowmeter, are caused to modulate the current drawn from a remote D.C. source 16 by a D.C.-to- D.C. converter 17, including a high-frequency oscillator Ql, Q2, Tl, and a rectifier 22, 24, and a pre-amplifier 14 having a resistive load 25. In operation, as the signals 12, 13 vary, the current through the resistive load 25 varies and the supply current drawn by the amplifier 14 from the D.C.-to -D.C. converter varies. This, in turn, varies the load on the D.C. source, and the resulting voltage variation across a shunt resistor 28 can be extracted at a terminal 15.