Phase Delay and Filter Lag Introduced by Capacitive Pressure Transducer Retrofits
Retrofitting capacitive pressure transducers introduces hydraulic dead-volume delay and digital ASIC filter lag that erodes control loop phase margin.
Excitation Frequency
Driver Signal
Alternating current measurement systems require a periodic input signal to stimulate a passive sensing element. The excitation frequency represents the frequency of this carrier signal, which is applied to transducers like linear variable differential transformers.
Resonant Behavior
Transducer design dictates the selection of this parameter to optimize sensitivity and avoid interference from ambient noise. Operating above the mechanical bandwidth of the moving core ensures that the sensor measures the physical position without being influenced by the oscillations of the electrical carrier itself.
Calibration Reference
Thermal drift and impedance variations in sensor windings can occur when this stimulation parameter is adjusted away from its specified value. Demodulator circuits must be synchronized with the excitation frequency to convert the modulated AC output back into a linear DC voltage. If the signal generator drifts, the resulting phase shift creates a measurement error that appears as a false displacement, highlighting the need for highly stable oscillator circuits.
Sensor Performance
Multi-sensor installations must coordinate these periodic signals to prevent crosstalk and beat frequencies between adjacent channels. Shielding cables and using a common master clock for the excitation frequency of all units eliminates these electromagnetic interactions. This practice ensures that multi-point measurements remain free from low-frequency fluctuations.