How does the anti-aluminium cut-chips model cylinder-type of the Omron E2EZ series proximity sensor work?
The circuit composition and the principle of operation are shown below.
1. Circuit composition (same as E2E)
High frequency oscillation type: The most general oscillation stop type.
Principle of operation
The aluminium chips with small density aren’t detected, and the detection of the sensing object is enabled by setting the oscillation frequency lower than usual, even though it has the same circuit composition as high frequency oscillation types, such as the E2E series.
There are characteristics that the eddy current causes in the sensing object, as it concentrates on the surface of the sensing object (skin effect). The lower the frequency is of the high-frequency magnetic field (oscillating frequency), the deeper the depth is that the eddy current flows (epidermal depth) by the high-frequency magnetic field from the proximity sensor.
By using this, the epidermal depth of the eddy current is deepened, and the influence is reduced (the magnetic flux is penetrated). By lowering the oscillating frequency of the sensor, the aluminium chip is penetrated, and the sensing object is detected.