Page 942 - ASEAN Chainflex Catalogue 2023

Example: tested, Structure and materials
tested, tested!
"Millions of double strokes"
in an energy chain
Profibus cables for constant Differences in service life
moving industrial use At the beginning of 2002, a test to determine the service life of
Profibus cables in a real application was commissioned in igus
®
For customers, it is hard to get an overview of the cable test laboratory. The aim was to examine any differences in the
market. Competition between cable suppliers is intensifying service life of igus’ CFBUS.001 chainflex cable and another
®
and manufacturers are outshining one another with their market leading Profibus cable. The parameters required for
promises to "guarantee service life for cables used in energy the test were selected on the basis of data contained in the
chains". Catalogues claim ten million - or even as many as 50 competitor’s catalogue:
million - double strokes service life of cables used in moving
applications.
Catalogue details Test item "A" Test item "B"
Taking a closer look at figures claimed, one must ask what Twin-core igus chainflex
®
®
testing was done, or how realistic the tests carried out actually Profibus cable CFBUS.001
were (for example length of travel, test radii, etc.) in order to Cross section (2 x AWG24)C (2 x 0.25mm )C
2
be able to provide such a guarantee. Even information stating To be determined in
that cables are tested in accordance with VDE (Association of Guaranteed service life Min. 4.0 million cycles a test Speed, approx.:
German electrical engineers) 0472, part 603, test method H, Bend radius > = 60mm 85mm
is not helpful when it comes to determining the service life of
a cable in energy chains, since the roller testing stand cannot Diameter 8.0mm 8.5mm
provide any conclusive results and there is no VDE test for Catalogue details Issue 2002 Issue 2002
special cables in energy chains. Table 2: Test parameters according to catalogue data of the
competition
A gliding application was chosen as a suitable test structure
since Profibus cable systems are often used here because
of their data integrity, particularly over long travel lengths and
transmission distances.
In order to be able to carry out non-destructive testing and
achieve a large number of bending cycles in a short period of
time, a genuine Profibus transmission path was constructed.
In a PC at the fixed end of the test chain there was a Profibus
master insert card. A connection to a profibus slave was
located on the moving end. This enabled the transmission rate
to be determined with the help of a diagnostic program. Any
data packets which might have been transmitted incorrectly
would be indicated. The highest-possible transmission rate of
12 megabits/s was set.
This important test, which commenced at the beginning of
2002 and is still in progress today, showed that only a relatively
low number of cycles (420,000) led to the total failure of test
item "A", which, according to the competitor’s catalogue,
should have functioned safely for at least 4.0 million cycles.
Thus the real lifetime reaches only about 10% of the stated
catalogue value.
On the other hand test item "B", the CFBUS.001, is still
undergoing testing without any faulty data transmissions. So
far, it has accomplished more than 14.0 million double strokes.
Picture 1: Gliding e-chain application as the basis of the test
®
936
Number of double strokes
The main reason for the major differences in service life is the
differing structural parameters of test item "A" and test item
"B" (CFBUS.001), as well as the different materials used for
producing the cables.
The conductor insulation of the bus pair comprised of a foam
material for both test items. The electrical properties of this
material ensured better transmission properties were achieved. Test item "A" Test item "B"
A disadvantage of this material, however, was its weakness
under mechanical stresses. The forces which affect the bus
CFBUS.001,
pair should be absorbed by the element insulation in order
to alleviate the mechanical stress on a conductor insulation. The extremely short pitch of the core strands ensure that no
Highly-elastic element insulation
great tensile or compressive force has an effect on a long
®
For this reason, test item "B" (igus ) was provided with a length of core. So relatively small bend radii with high cycle
rates can be realised.
mechanically superior, extruded TPE inner, or element,
gusset-filling insulation, in order to protect the bus pair against New: UL and CSA approval
mechanical influences during the bending procedure. The chainflex CFBUS cables are now also available for all standard
®
element insulation must be highly elastic. A mechanically
inferior element insulation made of inexpensive filling material field bus systems, complete with UL and CSA approval and
only serves to make the bus pair round, just like often used DESINA compliance. The highly abrasion-resistant, flame-
fillers or banding. It is not able to protect the bus pairs from retardant TPE outer jacket is extruded onto the fully braided
the high degree of mechanical stress present in the chain. shield with an optimised angle in order to provide the cable
Tensile and compressive forces which occur particularly affect with additional stability.
those parts of the cable core in which there is a break in the
element insulation. The bus elements wound with a particularly short pitch are
protected by means of a gap-filling, extruded TPE inner
jacket. The bus parameters required are fulfilled by means of
a combination of optimised insulating materials and production
procedures.
Test parameters As with all chainflex cables, the new standard field bus cables
®
Travel distance: S = 5.0m of the CFBUS series are now available ex-stock, without any
V = 3.5m/s cutting costs or extra charges for small quantities.
2
Acceleration, approx.: a = 7.5m/s
Bend radius, approx.: 55mm
The insulation of test item "B" (CFBUS.001) is on the one hand
characterised by a mechanically superior, gusset-filling TPE
element jacket, which mechanically relieves the bus pair, fixes Product information CFBUS
the cores in a defined position. Page 204
Position of the broken
element insulation
Position of the broken
core insulation
Picture 3: A mechanically low-quality element jacket can’t protect the bus pair against the high mechanical loads inside an
energy chain.
937