Title:
INPUT CIRCUIT OF TEMPERATURE MEASURING APPARATUS
Document Type and Number:
Japanese Patent JPH02198326
Kind Code:
A
Abstract:
PURPOSE:To make it possible to input and process the analog temperature signal from a thermocouple and the analog temperature signal from a three-wire type temperature measuring resistor by providing a second switch which can selectively switch a current source and one output line between the constant current source and one output line of the common output lines of the three-wire temperature measuring resistor. CONSTITUTION:In the input circuit of this apparatus, two output lines of a thermocouple 2 and two output lines of three output lines of a three-wire type temperature resistor 3 are commonly connected. In this way, the analog temperature signals from the different kinds of temperature measuring sensors, i.e. the thermocoupler 2 and the resistor 3 can be processed in the single input circuit. Specified currents are made to flow to the resistor 3 in the two directions. For this purpose, a first switch 5 switches one output line of the commonly used output lines of the resistor 3 and one output line, which is not used commonly, is provided. A constant current source 6 which supplies the specified current to the resistor 3 through a second switch 7 is provided at the front stage of the switch 5. In this constitution, the measured temperature can be obtained without being affected by the wiring resistance of the resistor 3.
Inventors:
DATE USHIO
TOMONARI NORIO
TOMONARI NORIO
Application Number:
JP1868189A
Publication Date:
August 06, 1990
Filing Date:
January 27, 1989
Export Citation:
Assignee:
YAMATAKE HONEYWELL CO LTD
International Classes:
G01K7/00; G01K7/02; G01K7/20; (IPC1-7): G01K7/00; G01K7/02; G01K7/20
Attorney, Agent or Firm:
Hiroaki Tazawa (1 person outside)
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