Chapter 13 - Tips and tricks for cable testing
PROFIBUS Tester BC-700-PB - User Manual
49
Cable testing error
message from
graphical user
interface of
PROFIBUS-Tester 5
Remedial measures - starting points for correctly
interpreting and repairing the indicated fault
Short circuit between A
and B
There is an unusual low ohmic or capacitive resistance
between signal lines A and B. Please search for damage on the
cable in the vicinity of the indicated error location. Possibly the
error could come from a severe crush of the cable or multiple
unpowered bus terminators.
Plus, be on the lookout for illegal spur lines and check, if
moisture penetrated the cabling or if the cabling is heavily
soiled.
Short circuit between A
and shield
Short circuit between B
and shield
Short circuit between A,
B and shield
There is an unusual low ohmic or capacitive resistance
between the mentioned signal lines and conductors. Possibly
the error could come from a severe crush of the cable or a
faultily assembled PROFIBUS-connector.
Plus, be on the lookout for illegal spur lines and check, if
moisture penetrated the cabling or if the cabling is heavily
soiled.
Capacitive Load / Spur
Line
There is an unusual capacitive load between signal lines A and
B and the shield conductor. Possibly the error could come from
an illegal spur line or from interference-suppression capacitors.
This is common usage with "over-compensated" or defective
PROFIBUS-devices.
Disconnect the devices in the vicinity of the indicated error
location and repeat cable testing in order to encircle the error.
Unknown error
The cable is still affected by unwanted reflections. Though it is
not possible to classify the fault indication. Please search for
damage on the cable in the vicinity of the indicated error
location and check if the PROFIBUS-connector has been
properly assembled.
Unwanted reflections may emerge from transitions between
media and signal conductors which have different impedance
values (e.g. two different cable types).
Sending pulse could
not be detected. The
cable is either too short
or not connected.
Please do not fall below the minimum cable length of 3 meters.
The intended use of cable testing requires a cable with
adequate length.
(Near-end) terminator
switched on
No reflections could be
detected. Please
remove terminators.
During the first of the three steps of cable testing the
PROFIBUS Tester requires an open cable on both sides.
However, the tester detected an ohmic resistance between the
signal wires and the resistance value is in the range of bus
terminators. Please make sure, that every bus terminator on
every PROFIBUS-connector is switched off or is deactivated.
Please take into consideration, that dip-switches for switching
on/off bus terminators may be defective.
