EoW January 2013

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Feature
Testing & measuring
January 2013 39
Solving answers to twisted pair wires
Twisted pair wires are used in signal-/control-/network- and fieldbus cables. The degree
of twisting is defined by the length of lay, or the twisting angle. The lay length (Snom)
of the paired wires influences the electrical and mechanical characteristics. If the
lay length deviates from the nominal value, various quality relevant defects appear.
If those defects are noticed by the customer, expensive callback activities will result and
controlling the lay length within the production line or rewinding station helps to avoid
such actions.
For controlling the lay length, Roland Electronic offers a method independent from the
kind of cable jacket, suitable for unshielded cables, performable within the production
line or the rewinding station: Detection of defects with eddy current encircling coil.
For detecting defects a special eddy current encircling coil is used, through which the
cable is led. The eddy current signals from the material are processed and evaluated
in the control unit SND40. In case of deviation of twisting, the control unit reports
this directly to the machine controls.
The inspection is not influenced by
running high voltage inspection.
Defect monitoring: Speed – 0.2...6m/s,
detection threshold – deviations >
0.5 Snom*, basic condition, length of
defect > 0.5 Snom*
* lay length
Further possible applications are:
Monitoring of the homogeneity of the
shielding meshwork, inspection for
homogeneity of strands, detection
of weldings and cable joints and
detection of material changes (eg of heating cables).
Roland Electronic GmbH – Germany Website:
Digital inline profile projector Geokon
KJM GmbH in Germany has developed a new high-precision 2-D profile inline
measurement system named Geokon. Four sensors acquire four images of the object
and the data is then analysed on computer
by image processing software.
Rectangular and complex profiles can be
measured. The profile types can be entered
as CAD-data in the DXF file format using the
“Teach-In” program.
With the “Teach-In” program, new products
can be defined very simply. The technical
drawing must be saved in DXF-format and
entered into the “Teach-In” program. Then
the measurement parameters are defined,
as in CAD programs, by entering dimensions,
creating a name (eg R15), defining tolerance
or intervention levels and saving the
parameters. For a new measurement, only
the article to be measured must be selected.
The results are displayed numerically as
well as graphically. An exclusively numerical
display of important dimensions in large
numbers can be selected. Values outside of
tolerance are highlighted in colour.
Measurement results are saved, printed or
transferred to computer-aided production
data acquisition PDA- or QM-systems,
according to customer requirements.
KJM GmbH – Germany
Website:
▲ ▲ Geokon from KJM GmbH
▲ ▲ Detection of defects with eddy current encircling coil