In applications with differential measurements, the question regularly arises as to whether the direction from which a height or position jump occurs can be derived from the measurement signal. Specifically, the question is whether the change in sign of the measured value allows conclusions to be drawn about the direction of movement of a test object.
Differential measurement is used to precisely determine differences in the height or position of an object using two P3PC sensors. By directly comparing both measured values, even small steps or deviations can be reliably detected.
In the test setup, two sensors, for example P3PC301 (red light) and P3PC342 (blue light), are mechanically mounted in alignment and aligned with the test object. Before starting the measurement, both sensors must be referenced. This is done via the sensor menu by selecting the “Referencing” menu item one after the other. Only then is a reliable differential measurement possible.
The sensors must be referenced before the start of the measurement to ensure precise differential values.
If the object is inserted from the left, the right sensor detects the step first – positive differential values are produced.
The measurements clearly show that the polarity of the differential values depends on the direction of entry. The change in sign can therefore be used to identify the direction from which a jump occurs – provided that the referencing and alignment of the P3PC sensors are implemented correctly.
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