Differences in service life
At the beginning of 2002, a test to determine the service life of profibus cables in a real application was commissioned in
igus’ test laboratory. The aim was to examine any differences
in the service life of igus’ CFBUS.001 chainflex® cable
and another market leading profibus cable. The parameters
required for the test were selected on the basis of data contained in the competitor’s catalogue:
||Test item “A”
|Test item “B”
||(2 x AWG24)C
||(2 x 0.25 mm2)C
||Min. 4.0 Mio. Cycles
||To be determined in
||> = 60 mm
||as in 2002
||as in 2002
Test parameters according to catalogue data of the competition
A gliding application was chosen as a suitable test structure
since profibus cable systems are usually used here because
of their data integrity, particularly over long lengths of travel
and long transmission distances.
In order to be able to carry out non-destructive testing and
hence achieve a large number of bending cycles in a short
period of time, a genuine profibus transmission path was
erected. 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 diagnosis program.
Any data packets which might have been transmitted
incorrectly could be indicated. The highest-possible transmission
rate of 12 megabits/s was set.
The fundamental 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) resulted in 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. The actual service life achieved deviates from
that indicated in the catalogue by a factor of ten.
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 cycles.