Loepfe YarnMaster Zenit, Instruction Manual

Page: 46 / 83

46 ZENIT
YARN STRUCTURE
SFI/D (Option)
Principle of the SFI/D Settings : Relative to the average
SFI/D value of the yarn (reference), upper and lower limits
are selected. When the current SFI/D value exceeds these
limits, the clearer performs a cut and the defect ive yarn is
drawn off the cone.
Reference (Constant / Floating)
ƒ
Fixed When the SFI/D value of a yarn is known, it is pos-
sible to enter a reference value between 5.00 and 25.00.
This ensures a constant SFI/D value in the selected limit
range.
ƒ
Float In this setting, the SFI/D reference value adjusts to
the general surface level of an article. The average SFI/D
value is formed over a suffi ciently long length. This pre-
vents, for example, that climatically caused surface varia-
tions of a yarn lead to excessive cuts of the clearer. As
soon as a bobbin has an excessive difference to the aver-
age value (
Ref ), it is recorded.
Note :
After an adjustment, the floating reference is cre-
ated anew and is valid only after a length of 4 km!
Ref
The average SFI/D value is indicated.
+ Limit /– Limit (%)
When the set limit values (±5% to ±40%) are exceeded, i.e.
as soon as the SFI/D value differs from the SFI/D refer ence,
a cut is made or the spindle is blocked with a corres ponding
suction length (80 m).
+ Cuts /– Cuts
The number of cuts due to a positive or negative deviation of
the yarn diameter are listed separately. This display makes
possible the optimizing of the setting. The total of the cuts will
be displayed in the
Monitoring Data menu.
Difference (%)
The difference of the value transferred last in the current
group, relative to the set reference, is displayed. The limits for
yarn clearing can be optimized on the basis of this difference
in percent.
Note :
A first-time display is provided immediately
for a constant reference, for a floating reference, after 4 km.
Comprehensive investigations have shown that the Surface
Index has a variation of approx. 10% for a bobbin (basis/
peak). This is mainly due to the tension differences during
ring spinning. These connections should be taken into ac-
count when setting the limits because such variations do not
normally cause significant quality deteriorations.