| 摘要 |
PURPOSE:To improve digital conversion resolution in an air conditioner with a digital conversion means and a failure detecting means by providing a failure detecting means for generating the output signal with specified voltage higher than that for catching capability of a temperature signal digital conversion means. CONSTITUTION:A control section 2 is provided with a voltage dividing resistors 302, 303 and a comparator 304 for detecting sensor failures. In this constitution, respective signal voltage VS, VR, VT, VC of set temperature 31, room temperature 170, adjusting door 142 and exhaust temperature 160 are digitized by A/D converter 21 to be sent to the input of a microcomputer 22. If the signal voltage is then less than 0.5V due to short-circuit or the like at that time the failure signal is generated. When the signal voltage exceeds the upper limit 4.5V which can be converted digitally and higher than the divided voltage 4.95V of resistors 302, 303, the comparator 304 generates the failure signal output to a microcomputer 22. Thus, failures at the low voltage side as well as the high voltage side can be detected to improve the resolution of digital conversion amount. |
