Chapter 13 - Tips and tricks for cable testing
50
PROFIBUS Tester BC-700-PB - User Manual
Cable testing error
message from
graphical user
interface of
PROFIBUS-Tester 5
Remedial measures - starting points for correctly
interpreting and repairing the indicated fault
Idle voltage too high
The ideal idle voltage between signal wires A and B of a cable
segment, which is properly terminated on both sides is
approximately 1.1 Volts. However, the PROFIBUS-Tester
detected voltage values higher than 3 Volts between the signal
wires A-B; A-Shield and/or B-Shield. These unwanted potential
differences obstruct the cable testing function and the test
results will become void. Plus, running leakage currents may
damage the PROFIBUS-Tester.
Please take care of proper functional earthing of your plant.
We recommend to remove the mains adapter and to operate
on the PROFIBUS-Tester 5 by means of the built-in battery if
you are receiving this error message. This will avoid damage
caused by leakage currents.
Please take also into consideration that the error cause could
be a defective RS-485 driver of a PROFIBUS-device.
Troubleshooting EMC and earthing issues are a highly complex
field of activity. Therefore it is recommended to ask service
providers which are primarily specialized in troubleshooting the
above mentioned issues.
Far-end / Near-end
terminator not powered
The corresponding bus terminator has been switched on, but
the terminator is improperly powered by 5 V supply voltage, yet.
During the cable testing the PROFIBUS Tester requires a
properly terminated cable at the far end (2nd test step) or on
both sides of the cable segment (3rd test step). A properly
terminated cable segment consists of activated and powered
bus terminators on both sides of the cable.
Please make sure that the corresponding PROFIBUS-device at
the corresponding end of the cable segment is powered. Plus,
the activated bus terminator is properly plugged to a powered
PROFIBUS-device.
No terminator detected
There is neither an unpowered bus terminator nor there was
detected a bus terminator at all in the respective cable
segment.
During the cable testing the PROFIBUS Tester requires a
properly terminated cable at the far end (2nd test step) or on
both sides of the cable segment (3rd test step).
When using D-sub connection, activated bus terminators are
only effective at the incoming connector of PROFIBUS-
connectors. The incoming connector is marked with "IN", an
incoming arrow or "A1/B1". Please be also on the lookout for
PROFIBUS-cables which have been connected by mistake to
the outgoing connector.
