Dürkopp Adler 550-D800 Operating Instructions Manual page 47

Operation
The Skip Stitch Detection assembly comprises the following components:
Information
Fig. 33: Skip stitch detection (2)
(4) - Skip Stitch Detection (SSD)
In the menu Setup > Components the check box Skip Stitch
Detection (SSD) (4) must be turned on.
Set the mm value in the section Bobbin observance from (5) starting
with which the SDÜ sensor will be active (the bobbin will not start rotating
immediately even though the machine is already sewing).
The value is based on experience and may vary with the bobbin,
the thread and the thread tension (preset value = 25).
Operating Instructions 550-D800 - 01.0 - 05/2023
• Enlacement check (UK): This sensor checks prior to each stitch if
the needle thread is pulled around the bobbin by the hook.
• Bobbin rotation monitor (SDÜ): The sensor checks if the bobbin
rotates during the sewing process. If the hook thread is pulled off
the bobbin correctly, sewing without a hook thread (false sewing) is
certain not to take place.
• Remaining thread monitor: The sensor monitors the hook thread
quantity on the bobbin inside the bobbin case. If the light beam
from the light barrier is reflected off the flat (2) during sewing, a
message will be displayed on the control panel. This signals that
the hook thread quantity is running low.
The user can finish the seam and change the bobbin afterwards
( p. 32).
(5) - Bobbin rotation monitor
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