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The Textile Magazine
DECEMBER 2011
sired or undesired double insertion. But no other infor-
mation is transmitted to the loom other than the “go / no
go” decision made by the detector itself.
In most situations, weft detectors require significant
time and attention in the creeling of packages and the
thread-up of weft yarns through the detector eyelets.
Double insertion must originate and be maintained
from designated eyelets, and it is not always possible
to change. Also, mixing of the same weft in single and
then in double insertion is not always possible. Fur-
ther, even if the detector offers an individual sensitivity
setting for each eyelet, the procedure is complex and
requires an experienced technician.
At ITMA 2011 in Barcelona, ITEMA introduced the
Maestro weft monitoring system on its new Silver 501
rapier machine. Maestro, unlike any of its competitors,
uses a special weft detector that transmits signals from
each eyelet to the micro-processor of the loom. Innova-
tive software from the loom’s micro-processor allows
real time analysis of the signal and thus efficient han-
dling of all weft breakage conditions.
The weft detector has been designed to produce a nu-
merical value for each of the 8 or 12 eyelets of the detec-
tor. If no weft is inserted for a given position the signal
value will be extremely low (the signal noise level). If
a weft yarn is moving in the eyelet, the numerical value
can go up as high as 4000, thus offering a very good
signal/noise ratio.
For each pick insertion, the 8 or 12 numerical values
are continuously transmitted to the loom’s micro-proc-
essor, multiple times for each pick. In fact, the numeri-
cal values are transmitted for each degree of the weav-
ing cycle. The data communication between the weft
detector and the loom’s electronics is handled by a very
fast and secure means of data communication. Clearly
this weft monitoring method also requires a fast loom
micro-processor.
With ITEMA’s new electronic NCP (common elec-
tronic platform for all ITEMA’s loom types), which was
also introduced at ITMA 2011, the required computa-
tion power is guaranteed even at extremely high rapier
weaving speeds; such as the 750 RPM demonstrated on
the Silver 501.
With transmission of the numerical values, the soft-
ware is capable of drawing the insertion curve for each
eyelet of the weft detector. This curve can be viewed on
the touch screen display of the weaving machine. The
insertion curve is available for each of the 8 or 12 eye-
lets of the weft detector.
Typical to other weft detection systems, the sensi-
tivity and control zone have to be defined. With the
Maestro System, the control zone is defined specifying
the degree in the weaving cycle for the start and stop of
the two zones in which the weft insertion is controlled.
The first zone goes from the beginning to the middle of
the insertion and the second zone from the middle to
the end. In each of the two control zones, the software
will check if the numerical value of the inserted weft is
above the threshold. The thresholds are predetermined
and defined for each eyelet. This is an easy procedure
by using the up/down arrows on the touch screen dis-
play. Therefore, the need to use potentiometers or other
setting methods is eliminated.
The individual sensitivity setting or definition of the
threshold does not make the Maestro more expensive.
All functionalities are handled through software. Dur-
ing weaving Maestro will continuously compare if the
numerical values transmitted by the weft detector stays,
Fig 2: the touch screen console allows the weaver
and the technician to operate the Silver 501 in a very
user friendly way.
technology