Communications: electrical – Systems – Call station
Patent
1978-05-15
1980-03-11
Caldwell, Sr., John W.
Communications: electrical
Systems
Call station
324 60CD, G08C 1900, G01R 2726
Patent
active
041930630
ABSTRACT:
The displacement of the diaphragm in a differential pressure sensor of the differential capacitor type produces an output signal substantially linearly related to the displacement. The capacitors are charged in parallel from a constant current source for a fixed period of time and discharged through separate discharge circuits for another fixed period of time. An integrating differential amplifier connected to the two capacitors as they discharge produces an output signal related to the area between the two discharge curves which is substantially linearly related to the extent of displacement of the diaphragm of the differential pressure sensor. The output from the amplifier is used to control the current output from the device.
REFERENCES:
patent: 2968031 (1961-01-01), Higa
patent: 3135916 (1964-06-01), Tannenbaum et al.
patent: 3271669 (1966-09-01), Lode
patent: 3318153 (1967-05-01), Lode
patent: 3456132 (1969-07-01), Dechelotte
patent: 3646538 (1972-02-01), Frick
patent: 3656000 (1972-04-01), Neathery
patent: 3967064 (1976-06-01), Sigworth
patent: 4040041 (1977-08-01), Fletcher et al.
"A Two-wire, 4-20 MA Flow Transmitter Using A Capacitive Sensor," Control Elements Conference, vol. 1, Apr. 30-May 4, 1973, pp. 1-8.
"Mechanical Input Transducers", Instrumentation in Scientific Research, pp. 67-69.
Hitt James J.
Mergner George C.
Caldwell Sr. John W.
Groody James J.
Leeds & Northrup Company
MacKay Raymond F.
Miller, Jr. William G.
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