Lenze CANopen control technology - Manual (Page 24)

Control technology | CANopen communication manual
Technical data
Bus cable length
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L
DMS 4.2 EN 07/2011 TD17
5.4.3 Check use of repeater
Compare the values from the tables Total cable length
( 22)
and Segment cable length
( 23)
.
 If the total segment cable length is shorter than the total cable length to be
implemented, either repeaters must be used or the cable cross-section must be
increased.
 If, due to the use of repeaters, the max. possible total cable length is reduced to a value
smaller than the total cable length to be implemented, either the cable cross-section
must be increased and the number of repeaters must be reduced or the baud rate must
be reduced.
 The use of another repeater is recommended as ...
– Service interface
Advantage: Trouble-free coupling during bus operation is possible.
– Calibration interface
Advantage: The calibration/programming unit remains electrically isolated.
Example
Given
Total cable length to be
implemented
450 m
Number of nodes 32
Cable cross-section 0.50 mm 2 (AWG 21)
Baud rate 125 kbit/s
Used repeater Lenze repeater EMF2176IB
Reduction of the max. total cable
length per repeater (EMF2176IB)
30 m
Results
Max. possible total cable length
600 m
(cp. table Total cable length ( 22) )
Max. segment cable length 360 m
(cp. table Segment cable length ( 23) )
Comparison The max. segment cable length is shorter than the total cable length to be
implemented.
Conclusion After the determined max. segment cable length of 360 m at the latest, a
repeater must be used.
Results with 1 repeater
Max. possible total cable length
570 m
(Reduction of the Total cable length ( 22) by 30 m)
Total segment cable length 720 m
Comparison Both the possible total cable length and the segment cable length are longer
than the total cable length to be implemented.
Conclusion One repeater suffices to implement the total cable length of 450 m.