Chapter 9 - Tips and tricks for cable testing
Copyright 2016 Softing Industrial Automation GmbH
47
Cable testing error message
displayed on BC-700-PB
Remedial measures - starting points for correctly interpreting and
repairing the indicated fault
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". În addition check for PROFIBUS-cables which have been connected
by mistake to the outgoing connector.
Far-end / Near-end
terminator wrong or not
adapted.
The PROFIBUS Tester detects an ohmic resistance between the signal
wires A and B, but the resistance value is not as expected in the range
of a bus terminator.
Make sure, that the bus terminator is properly powered and the
PROFIBUS-connector has been properly powered. Take into
consideration that multiple bus terminators may be switched on and
that dip-switches for switching on/off bus terminators may be
defective (due to aging and soiling).
Line A and B interchanged
The green and the red signal line are interchanged. Possible cause
might be a PROFIBUS connector which is assembled improperly. Please
bear in mind that after having two times interchanged line A and B, this
error cannot be recognized anymore. Only when interchanging both
lines for a third time, you may recognize the error.
Typically, the tester will not return a measured distance. In order to
localize the fault location we recommend shortening the respective
cable segment step by step by switching on bus terminators within the
cable segment. Repeat the cable test after each shortening procedure
until the error is no longer reported. The last active bus terminator is
the faulty one.
Near end terminator was
powered by internal 5 V
power supply.
This message is a note and not an error message. The cable test has
been passed successfully. The bus terminating resistor has been
switched on at the test location but is not powered via a PROFIBUS
station. Possible causes are: The related cable end is not connected to
an activated PROFIBUS station or the 5 V power supply of the related
PROFIBUS station is defective. The PROFIBUS tester was able to supply
the bus terminating resistor with its tester-internal 5 V power supply.
9.3 Metering the cable segment length correctly
Directly after starting the cable test function you will see the actual segment configuration. In the
context of cable testing it is recommended to provide the number of connectors and connected devices
in the respective cable segment. The provided number of these elements should be as precise as
possible in order to correctly detect cable segment length or the distance to the error. This chapter
illustrates, how connectors and devices influence the detection of the cable length.
To Next Page
Loading...