Driver electronics can be configured as masters or slaves. The master sets the synchronization for the slaves in multiple channel systems . The electric field from the probe sensor is seeking a conductive surface. For this reason, capacitance sensors are not effected by the target material prov ided that it is a conductor. Because the electric field from the sensor stops at the surface of the conductor, target thickness does not effect the measurement.
Surface finish can effect the measurement.
Capacitance probes will measure the average position of the target surface within the spot size of the sensor. Capacitance probes are most often used to measure the change in position of a conductive target. But capacitance probes can be very effective in measuring presence, density, thickness, and location of non-conductors as well. Non-conductive materials like plastic have a different dielectric constant than air. The dielectric constant determines how a non-conductive material effects capacitance between two conductors.