Title:
RESISTANCE BULB TEMPERATURE CONVERTER
Document Type and Number:
Japanese Patent JPH01291132
Kind Code:
A
Abstract:
PURPOSE:To always measure a temperature with high accuracy by changing a dynamic range of an A/D converter, based on a result of comparison by a comparing means. CONSTITUTION:A constant current (i) from a constant-current source 3 flows to a resistance bulb 1, and in one end of a lead wire 2, voltage signals VA-VC are generated, respectively. These voltage signals are selected successively by a switch 4, and converted to digital signals by an A/D converter 5. Also, a wiring resistance arithmetic means 61 calculates a wiring resistance r3 of a signal path. A comparing means 62 compares a value of this resistance r3 and a prescribed wiring resistance value which has been set in advance, and by its results, whether a current limiting resistance has been inserted into the signal path or not is known. When the wiring resistance is larger than a prescribed value, it is decided that the current limiting resistance has been inserted, and a dynamic range of the converter 5 is set to a regular mode, and when the wiring resistance is smaller than the prescribed value, it is decided that the current limiting resistance is not inserted, and the dynamic range is switched so as to become a high resolution mode.
Inventors:
FURUKAWA YOTA
YAMAGUCHI KENJI
YAMAGUCHI KENJI
Application Number:
JP12020988A
Publication Date:
November 22, 1989
Filing Date:
May 17, 1988
Export Citation:
Assignee:
YOKOGAWA ELECTRIC CORP
International Classes:
G01K7/00; G01K7/20; G08C25/00; (IPC1-7): G01K7/00; G01K7/20; G08C25/00
Domestic Patent References:
| JPS5741798A | 1982-03-09 | |||
| JP61180399B | ||||
| JPS6253328B2 | 1987-11-10 | |||
| JP56071629B |
Attorney, Agent or Firm:
Shinsuke Ozawa
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