Patent ID: 8653833

Claim:
A method comprising: (a) providing a signal generator, the signal generator for generating a probe signal having at least one predetermined characteristic and comprising at least a digital to analog converter; (b) providing a signal converter, the signal converter for generating a digital representation of at least one analog input signal of a plurality of analog input signals and comprising at least one of an analog to digital converter and a multiplexer; (c) providing a sensor, the sensor comprising at least a first electrical contact and a second electrical contact; (d) providing a reference impedance; (e) applying the probe signal at least one of continuously and selectively to at least one of the first electrical contact of the sensor and the reference impedance; (f) providing an impedance connect circuit, the impedance connect circuit comprising at least a switch for selectively connecting at least one of the second electrical contact of the sensor and the reference impedance to the signal converter; (g) providing an analysis circuit, the analysis circuit for receiving at least a digital representation of the generated probe signal and a digital representation of the at least one analog input signal, performing a first process upon the digital representation of the generated probe signal to determine at least a characteristic of the probe signal, performing a second process upon the digital representation of the at least one analog input signal in dependence upon at least the determined characteristic of the probe signal to generate at least one of a real component and an imaginary component of the digital representation of the at least one analog input signal, applying a correction to at least the imaginary component, and determining an impedance of the sensor in dependence upon at least the reference impedance and the at least one of the real component and the imaginary component of the digital representation of the at least one analog input signal; and (h) at least one of storing the determined impedance within a first memory, displaying a measurement to a user, the measurement determined in dependence of the determined impedance, and using the determined impedance as a control parameter to a dispensing circuit.