Excitation Scaling
Measurement configurations derive output digital readings directly as a fraction of the excitation supply voltage driving the bridge or sensor network. A ratiometric measurement system eliminates supply voltage noise and absolute drift errors by utilizing the excitation voltage as the reference input for the digitizing converter. The technique loses effectiveness when sensor excitation voltage differs dynamically from analog-to-digital converter reference input voltage.
Drift Cancellation
Variations in sensor supply voltage scale both sensor output voltage and converter reference voltage proportionally. Because the analog-to-digital converter evaluates input signal relative to its reference voltage, absolute supply fluctuations cancel out completely in the output digital code. Precision voltage references become unnecessary for sensor excitation when ratiometric architecture is maintained across the full signal chain.
Error Suppression
Common-mode supply noise present on sensor excitation lines cancels out during conversion processing. Lead wire resistance drops affect sensor excitation and reference inputs equally when sensed through kelvin connections. Long cable runs in industrial environments introduce stray pickup that degrades ratiometric cancellation if high-frequency noise exceeds converter common-mode rejection limits.
Thermal gradients along input wiring create parasitic thermoelectric voltages that bypass ratiometric cancellation mechanisms.
Reference Standard
Calibration procedures verify converter output codes against precise voltage ratios using ratiometric inductive voltage dividers. Precision laboratory standards quantify ratio accuracy across full digital input ranges. Certificates certify ratio linearity independently of absolute voltage accuracy.
