Fault analysis of temperature sensor (Part one)
Temperature sensor is a small part, but it plays an important role in monitoring system or control system. No matter how tall on if the temperature sensor fails, the system can only be shut down or shelved problems is tantamount to the hand eye ear nose skin sensory system, not perception of the outside world, and sound, and the importance of self-evident truth. Therefore, it is essential to guarantee the normal work of the temperature sensor at the same time, when the temperature sensor has a fault as soon as possible to find the cause of the fault, the normal work of the recovery system in a timely manner, which is also a necessary on-site staff, maintenance personnel, engineers and technicians of the quality and ability.
The reason of the temperature sensor fault is simple and complex, and must be analyzed in detail. The author combines ten years of production and work experience, simple analysis is as follows.
1. Make sure the temperature sensor is out of order. Seemingly a nonsense, in fact very important. When many technicians have problems at the scene, it is always the first time to think that the temperature sensors are broken and take it for granted that the temperature sensors are out of order. The failure of the first time, think of the temperature sensor, indicating the direction and ideas correctly, to deal with any problems from simple to complex, but most probably it did not actually happen is too subjective and arbitrary, is not conducive to the rapid identification of problems. How do you make sure that the temperature sensor is out of order? Very simple; — — check what you think is bad or change the new product directly.
2, check wiring. The sensor outside the system fault is not in the scope of analysis (another text analysis), therefore, a clear sensor is broken, then is to check the connecting line, including sensors and instrument, acquisition module connecting line, connecting wire sensor and the sensor, the sensor wire, in short, is to identify and remove the line the connection is not strong, resulting in false fault and short circuit and other reasons, to reduce the cost of maintenance and repair.
3. Determine the temperature sensor type. This is a frequently made low-level mistake. There are many kinds of temperature sensors, resistors, analog, digital and so on. As technicians, first of all, you should know how to judge. The resistance type use a multimeter resistance can immediately determine quality, temperature, temperature, resistance value; you can use the analog oscilloscope, see the amplitude and waveform of output voltage or current, further judgment; digital has little trouble, because the general internal digital temperature sensor is a piece of integrated circuit, and single-chip communication in order to determine. You can test it individually with your own microcontroller, or with a manufacturer or a general purpose meter. Digital temperature sensor is generally not allowed to directly measured with a multimeter, because of high voltage or burn “ &rdquo chip;, or lead to new circuit failure, thus unable to determine the real cause of the failure.
4, the real fault. The most direct is that no matter how you toss, sensors do not respond, this is the easiest conclusion. Bad judgment is also to let the vast number of technical personnel distress, is that kind of “ when good and bad ” “ not good or bad ” for example, the temperature value is incorrect, inaccurate, abnormal, jump, etc.. These phenomena can be basically concluded that the temperature sensor failure, is the problem of processing technology. These failures need to be repaired or replaced by the manufacturer. Therefore, the choice of temperature sensor manufacturers, the choice of mature technology, long production period, reliable quality and stability of the manufacturers is essential, you can do it with half the effort.