Segment Voltage Is Mea- Sured As Zero. Segment Is Unpowered; Cause(S); Trunk Breakage Between Fieldbus Power Supply And First Device Coupler; Not Enough Terminators - Pepperl+Fuchs HD2-DM-A Manual

Advanced Diagnostics
Appendix
ID
177
178
179
182
183
184
185
188
189
190
191
192
180
Phenomenon
The segment is powered
and communication is
active, but no devices are
detected
Segment voltage is mea-
sured as zero. Segment is
unpowered
Segment voltage is "Out of
specification"
Both fieldbus power sup-
plies report failure
No fieldbus power supply
installed
Segment voltage is mea-
sured as zero. Segment is
unpowered
Segment voltage is "Out of
specification"
Signal level is is too high,
only host is active and Seg-
ment is powered
Signal level of one or more
devices is too high and
devices are missing com-
pared to commissioning
Signal level of one or more
devices is too high
Signal level is too low:
OOS/MR
Signal level of one device
is MR/OOS (too low), sig-
nal level of others is OK

Cause(s)

Wrong fieldbus type
selected
Power supplies failed for
the segment
Power supply module
defect, Voltage is OOS
Trunk short circuit
Power supplies failed for
the segment
No power supply module
installed
Trunk short circuit
Fieldbus power supply
failed
Fieldbus power supply
removed
Terminal failure: loose con-
nection
Diagnostic device is
wrongly or not connected
to the segment
Power supply module
defect, Voltage is OOS
Trunk breakage between
fieldbus power supply and
first device coupler
Trunk breakage between
device couplers

Not enough terminators

Too many terminators

Terminal failure: corrosion
Device malfunction: Signal
level is too low
Too many terminators
Action(s)
Set fieldbus type to FOUN-
DATION Fieldbus or PRO-
FIBUS PA
Check and replace fieldbus
power supplies
Replace power supply
module
Check trunk. If no spur
short circuit protection is
installed, also check spurs.
Check and replace fieldbus
power supplies
Install power supply mod-
ule for this segment
Check trunk. If no spur
short circuit protection is
installed, also check spurs.
Replace fieldbus power
supply module
Install fieldbus power sup-
ply
Check all terminals for cor-
rect connection
Check wiring connection to
the segment
Replace power supply
module
Check trunk, fieldbus
power supply terminals
and first device coupler
Check trunk cable and
device coupler terminals

Check if a terminator is

installed on both ends of

the trunk

Check that one terminator
is installed on each end of
the trunk cable, but no
more than these two in total
Check if the resistance of
any terminal is too high
Replace device
Check that one terminator
is installed on each end of
the trunk cable, but no
more than these two in total