Broken wire method of detection null of resistance temperature sensor input processing

摘要

PURPOSE:To prevent abnormal data which is generated owing to the open circuit of a conductor connecting a resistance bulb from being handled as normal data by removing the abnormal data before a disconnection decision reference value is reached. CONSTITUTION:When the decision reference begins to be started, a voltage V1 obtained at a 1st sample point is compared with the disconnection decision reference voltage VT at ST1 to make an advance to ST3 when V1 VT or decide the open circuit at ST6. At ST3, it is checked whether or not V1 which is sampled currently rises exceeding V2 sampled last time by a specific quantity DELTAV1 and when not, this V1 is regarded as current normal data at ST4; and a return to ST1 is made and next V1 is sampled. When the voltage rises exceeding DELTAV1 at ST3, the last V1 is held as current V1 at ST5 and a return to ST1 is made. Thus, the abnormal data is prevented from being handled as normal data.