OPTRONIC LVMC, Руководство пользователя, Страница: 27 / 97

Interface A2, Release Date: 02.03.2022 Page 27 LVMC User Manul A2 - 499.027.82
OPTRONIC AG
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CH-9403 Goldach Phone: +41 (0)71 844 02 00
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e-mail: support@optronic.ch
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4.22 Measurement Inaccuracy and Repeat Accuracy
A light curtain is specified for a given resolution. This corresponds to the minimum object size that can be
detected by the LVMC. The maximum measuring inaccuracy depends mainly on the object size, but also on
the dimension of the light curtain.
As the measurement at the edges of the sensing area is affected, the measuring inaccuracy can only be
specified in an area with a minimum distance r from the edges of the sensing area. The distance r depends
on the width of the sensing area and is defined as follows:
For light curtains up to and including 150mm sensing area width: r=5mm
For light curtains with a sensing area width greater than 150mm: r=10mm
For a light curtain with sensing area width b, the expected maximum measuring inaccuracy, i.e. the maximum
deviation d from the real object size g, can be calculated according to the following formula, assuming that
the environmental conditions are good:
d = (0.0006*b/1.0mm+0.02)*g+(0.002*b+0.2mm)
Thus, under good environmental conditions, a light curtain with 100mm sensing area width measures an
absolutely vertically inserted and pulled out non-transparent and non-reflecting cylinder with a given diameter
g at a minimum distance of 5mm from the edges of all four sides of the sensing area as follows:
Maximum deviation: d = 0.08*g+0.4mm
Minimum value: a = g-d = 0.92*g-0.4mm
Maximum value:
b = g+d = 1.08*g+0.4mm
Diameter
g Maximum Deviation
d Minimum Value
a Maximum Value
b Relative Maximum
Deviation
1mm 0.5mm 0.5mm 1.5mm +-48%
2mm 0.6mm 1.4mm 2.6mm +-28%
5mm 0.8mm 4.2mm 5.8mm +-16%
10mm 1.2mm 8.8mm 11.2mm +-12%
20mm 2.0mm 18.0mm 22.0mm +-10%
In order to be able to achieve the stated values, good environmental conditions are required. Environmental
influences such as electromagnetic fields, light flashes, vibrations and pollution must be within tolerable
limits. In addition, the object must not be translucent or reflective.
If an object to be detected passes the sensing area reproducibly at the same position and in the same orien-
tation, then the measurement repeatability under good environmental conditions is + -0.2 mm.