Stability The ability of a meter to maintain certain characteristics over time within the specified operating conditions is called stability (degrees). Instrument stability is a performance indicator that chemical industry instrumentation workers are very concerned about. Because the environment in which chemical companies use meters is relatively poor, the measured temperature and pressure of medium are also relatively large. In this environment, the use of meters will reduce the ability of certain parts of the meter to remain constant over time. Stability will decline.徇 Or characterization instrumentation stability has not yet had a quantitative value, chemical companies usually use instrument zero drift to measure the stability of the instrument. During the one-year operation of the instrument, there is no drift in the zero position. On the contrary, when the instrument is put into operation for less than three months, the zero point of the instrument is changed, indicating that the instrument is not stable. Instrument stability is directly related to the scope of use of the instrument, and sometimes directly affect the chemical production, the impact of instrument stability caused by the impact of the decline in the accuracy of dual instruments will have greater impact on chemical production. Poor instrument stability The instrument maintenance is also large, and it is the most undesirable thing for the instrumentation worker.

Reliability instrument reliability is another important performance indicator pursued by the instrumentation industry of chemical companies. The reliability and maintenance of the instrument are inversely related to each other. The high reliability of the instrument indicates that the maintenance of the instrument is small. On the contrary, the reliability of the instrument is poor, and the maintenance of the instrument is large. For the detection and process control instruments of chemical companies, most of them are installed on process pipelines, various types of towers, tanks, tanks, and vessels, and the continuity of chemical production, most toxic, inflammable and explosive environments, and these bad conditions give the instrument maintenance. Many difficulties have been added. One is to consider the safety of chemical production, and the other is to relate to the personal safety of the instrument maintenance personnel. Therefore, the use of inspection and process control instruments by chemical companies requires that the maintenance quantity is as small as possible, which means that the instrument reliability is required to be as high as possible.