I. Core Implementation Idea
Abandoning traditional fixed-parameter RC filtering, a configurable dynamic RC network + real-time interference frequency detection architecture is adopted. Based on the real-time acquisition of the dominant interference frequency, the optimal filtering parameters are automatically matched to minimize temperature measurement signal delay while ensuring full-band interference suppression.
II. Hardware Infrastructure
A multi-channel analog switch is used to switch capacitor arrays with different capacitance values, paired with fixed high-precision resistors, to form a multi-level switchable RC filter network.
A high-speed sampling unit is added to the filtering front end to acquire the spectral characteristics of the input signal in real time and identify the dominant frequency range of the current interference.
A microcontroller unit is provided to automatically switch the corresponding RC parameters according to the detected interference frequency, achieving dynamic adaptation.
III. Dynamic Adjustment Logic for Each Level
No interference/weak interference range (dominant interference frequency <10Hz): Automatically switches to bypass mode, RC filtering is completely disconnected, and the temperature measurement signal is passed through without delay, maximizing the preservation of temperature measurement response speed.
Low-frequency power frequency interference range (interference frequency 50~100Hz): Automatically connects an RC branch with R=15kΩ and C=1μF, with a filter cutoff frequency set to 10Hz, achieving attenuation of over 30dB for power frequency interference.
Medium-frequency interference range (interference frequency 1~10kHz): Automatically connects an RC branch with R=1.5kΩ and C=100nF, with a filter cutoff frequency set to 1kHz, filtering out mid-frequency spikes while keeping signal delay within 150ms.
High-frequency interference range (interference frequency >100kHz): Automatically connects an RC branch with R=100Ω and C=10nF, with a filter cutoff frequency set to 160kHz, quickly filtering out high-frequency electromagnetic pulses with almost no impact on temperature measurement response.
IV. Closed-Loop Calibration and Safety Constraints The system automatically scans the input interference spectrum every 30 seconds. If the interference frequency falls into a new range for three consecutive detections, it automatically and smoothly switches to the corresponding RC setting to avoid signal fluctuations caused by frequent jumps. Added hard time constant limit: Regardless of the setting, the total RC time constant is strictly controlled within 200ms to absolutely prevent excessive filtering from causing temperature sampling lag and temperature overshooting.
Retained manual locking function: For scenarios with extremely high response speed requirements, such as optical precision molding, the RC setting can be manually locked to prevent automatic switching and ensure process stability.
