SENSOR SYSTEM, AND FAILURE DETECTION METHOD FOR SENSOR SYSTEM

To provide a sensor system that can detect a failure in a DA converter, and a failure detection method for a sensor system.SOLUTION: A sensor system 1 comprises: a sensor element 3S to which a control current Ip is input; a DA converter 42 that outputs the control current; and a control unit 4C that generates a control current indication value Ipcmd and inputs the value to the DAC. The sensor system further comprises: an indication value generation unit 47 that, in place of the control current indication value, generates an inspection current indication value Chcmd to be input to the DAC in order for every generation period Tc; an inspection current detection unit 7 that detects an inspection current value Ichv of an inspection current Ich; an expected value calculation unit 8 that calculates an inspection current expected value IMchv that is an expected value of the inspection current value Ichv; a differential value acquisition unit 9 that acquires a differential value DIch between the inspection current value Ichv and the inspection current expected value IMchv; and a failure detection unit 10 that, through frequency analysis of a temporal change of the differential value DIch, detects a failure in a bit belonging to a low-order bit group BL of the DA converter 42.SELECTED DRAWING: Figure 4 【課題】 ＤＡコンバータの故障を検知できるセンサシステム、及び、センサシステムの故障検知方法を提供する。【解決手段】 センサシステム1は、制御電流Ipが入力されるセンサ素子3Sと、この制御電流を出力するＤＡコンバータ42と、制御電流指示値Ipcmdを生成してＤＡＣに入力する制御部4Cと、を備え、さらに、制御電流指示値に代えて、ＤＡＣに入力する検査電流指示値Chcmdを生成周期Tc毎に順に生成する指示値生成部47と、検査電流Ichの検査電流値Ichvを検知する検査電流検知部7と、検査電流値Ichvの見込み値である検査電流見込み値IMchvを算出する見込み値算出部8と、検査電流値Ichvと検査電流見込み値IMchvとの差分値DIchを取得する差分値取得部9と、差分値DIchの時間変化の周波数解析により、ＤＡコンバータ42のうち下位ビット群BLに属するビットについての故障を検知する故障検知部10と、を備える。【選択図】 図４