System for remote sensing of a physical parameter

Patent 4916643 Issued on April 10, 1990. Estimated Expiration Date:

January 13, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

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Inventors

Assignee

W.C. Heraeus GmbH

Application

No. 143567 filed on 01/13/1988

US Classes:

702/188, Remote supervisory monitoring340/870.17, Temperature374/100, TEMPERATURE MEASUREMENT (E.G., THERMOMETER)374/166At plural zones

Examiners

Primary: Lall, Parshotam S.
Assistant: Makay, Christopher L.

Attorney, Agent or Firm

Frishauf, Holtz, Goodman & Woodward

Foreign Patent References

3128706 DE. 11/13/1985

International Classes

G08C 019/12
G01B 007/26

Foreign Application Priority Data

1987-01-16 DE

Abstract

A temperature remote-measurement system features a central evaluation unit 10 for all measuring points connected to two conductors 12, 14, forming a main data bus. In the embodiment shown, three addressable bus switches 18-1, 18-2, and 18-3 are connected to the data bus. To each bus switch 18 are connected respective conductors 26, 28. These together form an auxiliary bus, which is either connected to, or disconnected from, the main data bus formed by conductors 12, 14, depending upon the position of breaker 20. To the auxiliary buses formed by conductors 26, 28 are connected sensing units 32-38, which can modulate (as measurement pulses) the current carried by the conductors 26, 28 and which respond to specific voltage pulses (control pulses) generated by the control unit 10 and carried over these conductors. Each of the sensing units 32-28 has a temperature sensor 39, a pulse generator 40 controlled by the frequency of the sensor output signal, and a switching stage 41 activated by the sensor signal, so that the sensing unit altogether generates a sequence of pulses, whose interval represents the temperature at the sensing unit. The system also includes a modulator 58 which uses at least one of pulse width modulation and pulse amplitude modulation.