FAQ No. FAQ03261
Question
How big does the slit have to be if an object is measured through
a slit with an Optical Displacement Sensor?
Answer
The basic conditions for creating a slit are as follows:
(1) It doesn’t block the transmitted beam.
(2) It doesn’t block the receiver sight of vision.
(These are essential conditions. If these were the only conditions, simply
widening the slit to the size of the emitter and receiver lenses will
suffice however, there is another condition.)
(3) Light must not reflect off the slit frame.
If light that is reflected off the object hits the frame of the slit and
is captured by the receiver, it can cause errors. Some light will hit the
frame of the slit regardless, in varying degrees, depending on the angle
and dispersion properties of the object.
Whether the amount of light that hits the frame of the slit affects the
measurement or not depends on the intensity of the reflected light, the
reflectance of the slit frame, and the required accuracy of the
measurements.
It is ideal if the slit frame is made from a thin material that doesn’t
reflect light (i.e., with a dull black surface). Check the accuracy when
checking the size of the slit.
Other Displacement Sensor FAQs
 Can the Z500/Z550 be used to measure the thickness of an object by connecting two Sensor Heads?
How can I change the analog output of 4 to 20 mA to 1 to 5 V?
What is the service life of the Z300?
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