外文翻譯----多傳感器的自我測(cè)量診斷系統(tǒng)(編輯修改稿)
2024-09-18 17:13 本頁面
【文章內(nèi)容簡(jiǎn)介】 desired accuracy is met. The process is repeated until the temperature measurement with a desired accuracy is obtained. III. SELFDIAGNOSIS The selfdiagnosis algorithm is a software controlled procedure to detect whether any of the sensors in the array is faulty, to isolate and deactivate any faulty sensors present and to pensate for the faulty sensors. The diagnosis assumes that the majority of the sensors in the array are in good order. A sensor is classified as faulty if its measurement is more than x℃ from the actual temperature .where x is a user defined value depending on the temperature sensor used and the accuracy required. In the prototype. In diagnosis, the same reference voltage is applied to the voltage parator for all the sensor outputs in a “read cycle’’. In principle, all the sensors are expected to produce the same digital outamp。 with two exceptions: when the reference voltage is very close to the voltage corresponding to the actual temperature 。 if the sensor is faulty and gives rise to an inaccurate output different film those of the majority sensors. Thus as the reference voltage applied to the parator is shifted between him V (min) to V (max), it should be able to separate the good and faulty sensors. This is illustrated in Fig. 3 where, as indicated, sensor 20 and 26 are filly. The diagnostic algorithm works as follows. At a certain temperature, a constant reference voltage is applied to the parator for all the sensors in the array. The total number of “ones” and “zeros” are counted and the majority state or “zero” is determined. A sensor that belongs to the minority state is likely to be faulty. Each sensor has a software status counter associated with it that is initially set to zero at the start of the diagnostic routine. This counter is incremented if the sensor was found to belong to the minority state. Incrementing the status counter of a sensor indicates a high probability that the sensor is faulty. In Fig. 3 both sensor 20 and 26 will have their software counters incremented for the V, level since they belong to the minority state. The constant reference voltage is shifted between the extreme ends of the voltage range through scanning (moving from V(min) to V (max) in fixed increments). For each diagnostic reference voltage applied, all sensor inputs are scanned (one “read cycle”). After the entire voltage range has been scanned, if the software counter of any sensor has been incremented by more than three times (in the prototype, this is equivalent to a 4℃ deviation from the actual temperature), then the sensor is deemed faulty and is deactivated. The faulty sensor is deactivated through software by discarding the binary reading produced by the faulty sensor at the parator that is read in by the microcontroller. Progressively shifting the diagnostic reference voltage from V (min) to V(max) can be very time consuming. For example, if the initial voltage range is and the step increment is then 100 diagnostic reference voltages (“read cycles”) need to be applied. To reduce the processing time of the diagnostic algorithm, successive approximation is used. The initial diagnostic reference voltage applied is in the mid value of the initial voltage range, . diagnostic scan is carried out. If the results from the “read cycle” show that there are more “ones” than “zeroes”, then the non
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