Tham khảo tài liệu 'understanding automotive electronics 5e episode 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | THE SYSTEMS APPROACH TO CONTROL AND INSTRUMENTATION 2 Figure Instrument Dynamic Error begins responding but cannot instantaneously change and produce the new value. After a time the indicated value approaches the correct reading presuming correct instrument calibration . The greater the bandwidth of an instrument or instrumentation system the more quickly it can follow rapid changes in the quantity being measured. In many automotive instrumentation applications the bandwidth is purposely reduced to avoid rapid fluctuations in readings. For example the type of sensor used for fuel quantity measurements actually measures the height of fuel in the tank with a small float. As the car moves the fuel sloshes in the tank causing the sensor reading to fluctuate randomly about its mean value. The signal processing associated with this sensor has an extremely low bandwidth so that only the average reading of the fuel quantity is displayed thereby eliminating the undesirable fluctuations in fuel quantity measurements that would occur if the bandwidth were not restricted. The reliability of an instrumentation system refers to its ability to perform its designed function accurately and continuously whenever required under unfavorable conditions and for a reasonable amount of time. Reliability must be designed into the system by using adequate design margins and quality components that operate both over the desired temperature range and under the applicable environmental conditions. BASIC MEASUREMENT SYSTEM The basic block diagram for an electronic instrumentation system has been given in Figure . That is each system has three basic components sensor signal processing and display. Essentially all electronic measurement systems incorporated in automobiles have this basic structure regardless of the physical variable being measured the type of display being used or whether the signal processing is digital or analog. Understanding automotive electronic instrumentation .
