When analyzing temperature instrument system failures, first of all pay attention to two points:
1. The system meters use electric meters for measurement, indication, and control;
Second, the measurement of the system instrument often lags behind.
(1) The indicator value of the temperature meter system suddenly changes to the maximum or minimum, which is generally a failure of the instrument system. Because the temperature meter system measures large lags, sudden changes do not occur. At this time, the cause of the failure of precession swirl vortex flowmeter is caused by the thermocouple, thermal resistance, wire breakage of the compensation wire, or failure of the transmitter amplifier.
(2) temperature control instrument vortex flowmeter system indicates rapid oscillation phenomenon, mostly caused by improper control parameter PID adjustment.
(3) The temperature control instrumentation system indicates the occurrence of large and slow fluctuations, which may be due to changes in process operations. If the process operation does not change at that time, it is likely that the instrument control system itself has failed.
(4) The temperature control system orifice flowmeter itself failure analysis steps: check whether the input signal of the regulator valve changes, the input signal does not change, adjust the valve action, adjust the diaphragm head diaphragm leak; check the regulator valve positioner input signal is Change, the input signal does not change, the output signal changes, the positioner has a fault; check the positioner input signal changes, and then check the regulator output if there is no change, if the regulator input does not change, the output changes, this time is the regulator itself malfunction.