| 摘要 |
PROBLEM TO BE SOLVED: To provide an A/D conversion device that can accurately detect whether or not there is an input side anomaly. SOLUTION: An A/D conversion device 100 includes: a plurality of input terminals T1-Tn; a multiplexer 2 for outputting one selected from analog signals SG1-SGn input into the respective input terminals; an A/D converter 4 for converting the analog signal to a digital signal; a switch circuit 5 for selecting a state in which the input terminals T1-Tn are grounded via pull-down resistances RD1-RDn or a state in which they are not grounded; and a CPU 1 having the multiplexer 2, the A/D converter 4 and the switch circuit 5 built therein. As to the selected analog signal SGi, the CPU 1 computes a difference between an A/D conversion value in the state in which the pull-down resistance RDi is connected between the input terminal Ti and a ground GND and an A/D conversion value in the state in which the pull-down resistance RDi is not connected, and if the difference is equal to or greater than a threshold, determines that there is an input side anomaly. COPYRIGHT: (C)2013,JPO&INPIT |
