Fault analysis of temperature control instrument system
www.mechnet com. Cn "> failure analysis of temperature instrument control instrument system: failure analysis steps of temperature control instrument system:
when analyzing the failure of temperature control instrument system, we should first pay attention to two points: the instruments of this system mostly adopt electric instruments for measurement, indication and control; the measurement of instruments of this system often lags behind greatly.
(1) The indication value of the temperature instrument system suddenly changes to the maximum or minimum, which is generally the instrument system fault. Because the measurement lag of the temperature instrument system is large, sudden changes will not occur. At this time, the fault causes are mostly thermocouple, thermal resistance, broken compensation wire or transmitter amplifier c: please check whether you press the "pneumatic zeroing key" and "deformation zeroing key" before the beginning of the experiment. If there is no failure, it is caused
(2) the indication of temperature control instrument system shows rapid oscillation, which is mostly caused by improper PID adjustment of control parameters
(3) the indication of temperature control instrument system fluctuates greatly and slowly, which is likely due to the change of process operation. Mouse data can be used on the experimental curve; If there is no change in the process operation at that time, it is likely to be the failure of the instrument control system itself
(4) fault analysis steps of the temperature control system itself: check whether the input signal of the regulating valve changes, the input signal does not change, the regulating valve acts, and the measurement benchmark is based on the shape and size of the test piece, and the diaphragm of the regulating valve diaphragm head leaks; Check whether the input signal of the regulating valve positioner changes. Only in this way can it stop one step further. The design input signal does not change, the output signal changes, and the positioner is faulty; Check whether the input signal of the positioner changes, and then check whether the output of the regulator changes. If the input of the regulator does not change, the output changes. At this time, it is the fault of the regulator itself