Control Cables; Detecting And Eliminating Emc Interferences - Lenze MOBILE DCU Hardware Manual

5.4.5

Control cables

Shield control cables to minimise interference injections.
ƒ
Connect the shield correctly:
ƒ
– Connect the shield of digital input and output cables at both ends.
– Connect the shield of analog input and output cables at one end of the inverter.
To achieve an optimum shielding effect (in case of very long cables, with high
ƒ
interference) one shield end of analog input and output cables can be connected to
PE potential via a capacitor (e.g. 10 nF/250 V).
5.4.6

Detecting and eliminating EMC interferences

Interference
Interference of analog
setpoints of the own or
other devices and
measuring systems
CAN time out
or
CAN Bus Heavy
EDSMDAG EN 2.0
Cause
Unshielded HV mains cable
Unshielded motor cable
Shield contact is not extensive enough
Shield of the motor cable is interrupted
by terminal strips, switched, etc.
Install additional unshielded cables
inside the motor cable (e.g. for motor
temperature monitoring)
Too long and unshielded cable ends of
the motor cable
CAN communication is disturbed
Ò
Installation
EMC−compliant installation
Control cables
Remedy
Use shielded cables
Carry out optimal shielding as specified
l
Separate components from other
component parts with a minimum
distance of 100 mm
l Use motor choke/motor filter
Install and shield additional cables
separately
Shorten unshielded cable ends to
maximally 40 mm
l Use cable according to CAN
specification
l
Wire terminals completely
l
Connect the shield with a good
electric conductivity
l Check terminating resistor
5
47