Vaisala K-PATENTS PR-23 AX Series, Instruction Manual

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5 Startup and use 37
Empty pipe Normal conditions
Figure 5.8 Typical optical images with IDS
Figure 5.9 A slope graph with IDS
It should be noted that the "empty" optical image may have vertical left and/or right
edge close to the edge of the image. In the example, only the right edge is visible.
5.4.3 Optical image with VD
A PR-23-GP can be ordered with option -VD, Vertical Borderline Image Detection. This
is typically used in a sugar vacuum pan. With vertical borderline the optical image is
without IDS, and the sides of the optical image are straight and slightly sloping. This
is achieved programmatically, the optical module in the sensor is the same as for a
PR-23-GP without the -VD option.
Empty pipe Normal conditions
Figure 5.10 Typical optical images with Vertical Borderline Image Detection