I. Core RC Performance Drift Monitoring Indicators
Actual Filter Cutoff Frequency Deviation: The deviation between the measured cutoff frequency of the RC circuit and the set value. A deviation exceeding 20% is considered excessive drift.
Interference Signal Attenuation Amplitude: The attenuation of the target main frequency interference signal after RC filtering. A deviation below 15dB is considered excessive drift.
RC Total Time Constant: The measured total time constant of R×C. A deviation exceeding 200ms is considered excessive drift, indicating a risk of temperature measurement lag.
Resistor/Capacitor Value Deviation: The deviation between the measured resistance and capacitance values of the RC network and their nominal values. A deviation exceeding 10% is considered hardware drift.
II. Signal Link Anomaly Monitoring Indicators
Temperature Reading Fluctuation Amplitude: Irregular fluctuations in temperature readings when the temperature controller is unloaded. A fluctuation exceeding ±2℃ is considered RC filter failure drift.
Temperature signal delay: The delay time for temperature changes at the thermocouple terminals to be transmitted to the temperature controller sampling terminal. A delay exceeding 2 seconds is considered excessive drift.
Signal ripple amplitude: The peak-to-peak value of the ripple in the filtered temperature signal output. A peak value exceeding 10mV is considered RC filter performance drift.
III. Specific Monitoring Indicators for Different Processes
Ordinary structural component processes: Temperature control overshoot amplitude exceeding 5℃ is considered a control anomaly caused by RC parameter drift.
Engineering component injection molding processes: Number of oscillations in the temperature control curve over 8 consecutive hours. A oscillation exceeding 3 times is considered excessive RC drift.
Optical-grade precision processes: Temperature difference at all measurement points throughout the flow channel exceeding ±1℃ is considered sampling imbalance caused by RC parameter drift.
Highly sensitive degradable material processes: Number of times an over-temperature trigger occurs without warning. Even one over-temperature trigger indicates RC drift and requires immediate calibration.
