附录A
A Multi-Sensor Bad TemDerature Measuring System with Self-Diagnosis
Abstract- A new multi-nsor bad temperature measuring system with lf-diagnosis is developed to replace a conventional system that us only a single nsor. Controlled by a 16-bit microprocessor, each nsor output from the nsor array is compared with a randomly lected quantid reference voltage at a voltage comparator and the result is a binary “one” or “zero”. The number of “ones” and “zeroes” is counted and the temperature can be estimated using statistical estimation and successive approximation. A software diagnostic algorithm was developed to detect and isolate the faulty nsors that may be prent in the nsor array and to recalibrate the system. Experimental results show that temperature measurements obtained are accurate with acceptable variances. With the lf- diagnostic algorithm, the accuracy of the system in the prence faulty nsors is significantly improved and a more robust measuring system is produced. Index Terms-Instrumentation and Measurement, Sensors.
异化翻译
我的初三生活作文Transducers
I. INTRODUCTION
Conventional nsing system us a single nsor to convert a measured into an electric signal. There is no built-in redundancy and the system is wholly dependent on the single nsor for its accuracy. Recently, a novel approach propod by the author in [l] makes u of the principles of successive approximation and statistical estimation to provide
俄罗斯概况a simple yet accurate estimate of the measured with only a small number of nsors. Replacing the single nsor with a multi-nsor array also improves the robustness of the system reducing system dependency on any single nsor. The system is still functional even with a few faulty nsors, though there will be a degradation in the accuracy of the
results. To overcome the degradation in the accuracy due to the prence of faulty n
sors, a lf-diagnostic algorithm is devid to determine and isolate faulty nsors so that the nsors are not ud in the determination of the temperature estimate. In this paper, the development of such concept into
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a practical system for temperature measurement is described.
II. SYSTEM ARCHITECTURE AND OPERATION
单价英语史家小学通州分校>tifoA. System Hardware Architecture
The hardware system consists of 36 temperature nsors in a ensure array, a signal conditioning circuit and a 16-bit micro- controller, as shown in Fig. 1. Each nsor, controlled by an analog switch, measures temperature and outputs a voltage. The output from all 36 nsors are fed into a switching
circuit. The switching circuit consists of a decoder and an analog multiplexer that is controlled by the software to quentially lect an output from all the 36 nsors. The lected output is fed into the signal conditioning circuit for processing before being
nt to the microcontroller. One complete “read cycle” involves reading the outputs from all 36 nsors. The nsors ud in the nsor array are calibrated beforehand to obtain their voltage-temperature characteristic. The aggregate voltage-temperature relationship for the nsor array was found to be linear over the temperature range to be measured, thus a simple linear equation is ud in the software algorithm to convert the voltage reading into a temperature reading.
B. Temperature measurement
jhuTo obtain an estimate of the output temperature, mathematical principles of successive approximation and statistical estimation are ud. The analog nsor output are quentially lected by the switching circuit and pasd onto the non-inverting input of a voltage comparator for
idle是什么意思digitization. A reference voltage that is determined by the software program is applied to the inverting input of the voltage comparator. If the analog nsor voltage is higher than the reference voltage then the output at the comparator is a binary “one”, els
e the result is a binary “zero”.
The initial reference voltage range of is established bad on apriority
knowledge of the characteristics of the temperature nsors and the temperature range to be measured. The voltage range is then quantized into m different levels with an equal step sue of where m is the number of nsors in the nsor array and reprents the maximum and minimum value of the initial voltage range before any successive approximation is carried out. The m reference voltages are randomly sorted. For each reading from the nsor array, a quantized reference voltage is randomly lected for comparison at the voltage comparator. This is to reduce the dependency of any nsor reading to the reference voltage applied. At the output of the comparator, a binary “one” or “zero” is produced. The quantized reference voltage is generated by the software algorithm and converted into an analog voltage through a 12- bit digital-to-analog converter PAC. One complete “read cycle” involves processing the analog nsor voltages him all 36 nsors to obtain 36 binary readings. The binary output from the comparator is fed to the
