OPD101
8
Matching value provided in [%]
Description
50
There is a 50 % match between the measured profile and the
activated reference profile.
The matching value to be tolerated must be determined by the user during set-up and should be
used as switching threshold for the following differentiation:
-
good parts
- bad parts
The transition between good parts and bad parts is determined by measurement and used as
switching threshold.
No particular switching threshold is recommended. It has to be determined according to the
respective application.
3.2.1 Fluctuation of the matching value
Natural fluctuations (noise, drift) affect the measured matching value.
As a rule, these measurement fluctuations cause the matching value to be < 100%, even if the taught
object is measured again.
The measurement uncertainty for the detection of height profiles is described using the following
figures:
Gz - accuracy in Z direction (profile height)
Gx - accuracy in X direction (profile width)
2
3
4
5
6
1
Fig. 3: Precision
1:
sensor
2:
measurement uncertainty
3:
object profile
4:
operating area
5:
accuracy in Z direction (Gz)
6:
accuracy in X direction (Gx)
This means that Gz/Gx also defines the:
•
minimum object height to be detected reliably
•
minimum object width to be detected reliably
The height profiles are internally detected by the sensor with a higher resolution than Gz/Gx.
Changes in object height/width can therefore be detected within the measurement uncertainty.
