Capacitive Proximity against Inductive Where the Target Material Changes
Metallic target variation demands Factor 1 inductive sensors to eliminate reduction factors, while polymer and liquid swaps require capacitive heads with active guarding.
Multi-Coil Design
Sensor Architecture
Inductive position sensors often utilize a configuration of multiple copper windings to improve spatial resolution and linearity. A multi-coil design employs one transmitter coil to generate an alternating magnetic field and two or more receiver coils to detect the position of a target. This layout allows the sensor to measure the differential voltage between the receiver coils, which varies with the position of the target.
The geometric arrangement of these windings determines the measurement range and the resolution of the sensor.
Measurement Precision
Differential signals are less sensitive to common-mode errors than single-coil measurements. By using a multi-coil design, the sensor can cancel out the effects of axial runout and supply voltage fluctuations. This cancellation improves the repeat accuracy of the sensor in high-precision positioning applications.
Temperature Compensation
Thermal expansion of the coil substrate can shift the electrical properties of individual windings. In a multi-coil design, the receiver coils are located on the same substrate and experience identical thermal conditions, which allows the differential circuit to balance out thermal drift. This ensures that the zero point of the sensor remains stable over a wide operating temperature range.
Mechanical Alignment
Mounting tolerances during assembly can introduce errors if the coils are not perfectly positioned. This requires precise alignment of the PCB layers and the transmitter target to avoid asymmetry in the output signals.