Recognising and eliminating EMC interferences
12
l
EDBEMVPBUS EN 2.2
4
Recognising and eliminating EMC interferences
Interference
Cause
Remedy
Bus cable is shielded insufficiently
Optimise the shielding of the bus cable:
•
Provide a large-surface contact of the bus cable shield
to the EMC shield sheet with shield clamps for each
station.
•
Interference of the fieldbus
communication after controller enable
•
Interference of communication at low
frequency
•
Yellow LED at the communication module
Interference injection via the motor
cable
Optimise the shielding of the motor cable:
•
Provide a large-surface contact of the motor cable
shield with the EMC shield sheet using shield clamps.
•
Provide a large-surface contact of the motor cable
shield with the motor; Use EMC cable glands.
•
Avoid interruption of the motor cable due to terminals
or contactors; Connect the shield to each clamping
point.
•
Yellow LED at the communication module
is blinking irregularly
•
Green LED at the communication module
is blinking sporadically
Interference injection via PTC
connection
Optimise PTC connection (terminals T1, T2):
•
Separate and shield PTC cable.
•
Use EMC kit when PTC cable and motor cable are
guided in one shield.
•
Remove PTC connection.
•
There is sporadically no data acceptance
from the fieldbus
•
Drive stops without being able to derive
the reason from C0135 (main control
Earth loops due to external voltage
source
Optimise external supply of the fieldbus modules:
•
Remove earth loops against module GND of the
external supply.
•
If necessary, use separate supply.
•
Do not use an external supply.
the reason from C0135 (main control
word), C0046 (setpoint) or C150 (status
word)
•
Drive sets error EER, although not
fi
d i C410/11 (FIXED FREE)
Insufficient earthing, insufficient
equipotential bonding of the whole
system
Optimise earthing and equipotential bonding of the whole
system
•
Connect all system components electrically with PE.
•
Install electrical isolation in the fieldbus (repeater).
,
g
configured in C410/11 (FIXED FREE)
•
Drive sets error CCR
Max. length of the bus cable is
exceeded
Observe the maximum bus cable length:
•
The maximum length depends on the baud rate (see
the corresponding Instructions).
•
Observe the exact specification of the bus cable (see
the corresponding Instructions).
Specification of the control cables
has not been observed
Use the appropriate cable:
•
Observe the exact specification (see the corresponding
Instructions).
8200EMV042
Fig. 5
Oscillograms of the PROFIBUS signals
PROFIBUS signal with interference voltage
PROFIBUS signal without interference voltage
Measuring points: A - B
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