Title:
INPUT CIRCUIT OF TEMPERATURE MEASURING APPARATUS
Document Type and Number:
Japanese Patent JPH02198327
Kind Code:
A
Abstract:
PURPOSE:To provide common use of an input circuit and to improve measuring accuracy by operating several units of switching means. CONSTITUTION:In the input circuit of this apparatus, two output lines of a thermocouple 2 which are selected with a first switch SW1 are commonly connected to two output lines among three output lines of a three-wire type temperature measuring resistor 3 which are selected with a second switch SW2. In this way, the analog temperature signals from the different kinds of temperature sensors, i.e., the thermocouple 2 and the resistor 3, can be processed in the single input circuit. Specified currents are made to flow to the resistor 3 in two directions. For this purpose, a third switch 3 which switches one output line of the commonly used output lines of the resistor 3 and one output line which is not commonly used is provided. A constant current source 6 which supplies the specified currents to the resistor 3 through a fourth switch 7 is provided at the front stage of the switch SW2. In this way, 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:
JP1868289A
Publication Date:
August 06, 1990
Filing Date:
January 27, 1989
Export Citation:
Assignee:
YAMATAKE HONEYWELL CO LTD
International Classes:
G01K7/00; G01L7/02; G01L7/20; (IPC1-7): G01K7/00; G01L7/02; G01L7/20
Attorney, Agent or Firm:
Hiroaki Tazawa (1 person outside)
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