Cross-Physics Sensor Replacement in Industrial Control Circuits
Cross-physics sensor retrofits require matching phase delay, thermal drift coefficients, and input filter bounds before changing the transduction element.
Target Material Permeability
Magnetic Conductance Property
Ability of a substance to support the formation of a magnetic field within itself determines the sensitivity of inductive and magnetic sensors. Higher target material permeability allows for easier detection at greater distances. This property is a measure of how much a material concentrates magnetic flux compared to a vacuum.
Flux Concentration
Ferrous metals like iron and nickel have high permeability and provide a strong path for magnetic lines of force. When these materials approach a sensor, they significantly alter the inductance of the internal coil. This large change in the magnetic circuit is easy to detect even in the presence of electrical noise.
Detection Sensitivity
Non-magnetic materials like aluminum or 300 series stainless steel have a permeability near one, which is the same as air. These targets do not concentrate the magnetic field and are therefore much harder for some types of sensors to see. Specialized sensors are required when the target material has low magnetic properties.
Material Grade
Small changes in the alloy composition of a metal can significantly alter its magnetic behavior. Cold working or heat treating stainless steel can increase its permeability and change the switching point of a proximity sensor. Consistent material sourcing is required to ensure that the detection system remains accurate across different batches of parts.