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Advanced Diagnostics
Appendix
ID
146
149
150
152
153
154
155
156
Phenomenon
Signal level of one or more
devices is too high
Segment voltage is mea-
sured as zero. Segment is
unpowered
The segment is powered
and communication is
active, but no devices are
detected
Noise "MR/OOS" for the
segment
Jitter of one device
"MR/OOS", jitter of other
devices OK
Unbalance is "OOS/MR" to
fieldbus +
Unbalance is "OOS/MR" to
fieldbus -
Noise of one device is
"MR/OOS", value of other
devices is not "MR/OOS"
Cause(s)
Not enough terminators
Fieldbus power supply
failed
Bulk power supply failed
Fieldbus power supply
removed
Cable breakage, short cir-
cuit or terminal connection
failure
Diagnostic device is
wrongly or not connected
to the segment
Wrong fieldbus type
selected
Noise injection on the field-
bus
Shield wiring / grounding
fault
Device malfunction: jitter of
a device is too high
Not enough terminators
Fieldbus impedance fault
Short circuit/leakage cur-
rent between fieldbus pos.
pole and shield/ground
Water ingress
Short circuit/leakage cur-
rent between fieldbus neg.
pole and shield/ground
Water ingress
Device injects noise
Action(s)
Check if a terminator is
installed on both ends of
the trunk
Replace fieldbus power
supply module
Check bulk power supply
Install fieldbus power sup-
ply
Check cabling and termi-
nals
Check wiring connection to
the segment
Set fieldbus type to FOUN-
DATION Fieldbus or PRO-
FIBUS PA
Check fieldbus cable for
correct shielding and
grounding. Check for exter-
nal noise sources.
Check fieldbus cable for
correct shielding and
grounding.
Replace device
Check if a terminator is
installed on both ends of
the trunk
Check if the fieldbus topol-
ogy is valid. Check noise,
reduce high noise values.
Remove connection
between pos. pole and
shield/ground
Check housings of devices
and junction boxes for
water ingress
Remove connection
between neg. pole and
shield/ground
Check housings of devices
and junction boxes for
water ingress
Check noise with the field-
bus oscilloscope. The
device showing high noise
values is not necessarily
the one injecting the noise.
177
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