Lenze EMF2181IB - Page 27

Installation
Electrical installation
Connection for the CAN bus
5
l
27
EDSMF2181IB EN 3.0
Check repeater application
Given:
l Baud rate: 125 kbit/s
l Cable cross−section: 0.5 mm
2
l Number of nodes: 28
l Cable length: 450 m
Test sequence Cable length See
1. Total cable length at 125 kbit/s: 630 m Tab. 5−1
2. Segment cable length for 28 nodes and a cable cross−section of
0.5 mm
2
:
360 m Tab. 5−2
3. Comparison: The value under point 2 is smaller than the required cable length of 450 m.
Conclusion
l It is not possible to use a cable length of 450 m without installing a repeater.
l After 360 m (point 2) a repeater must be installed.
Result
l The Lenze repeater, type 2176 (cable reduction: 30 m), is used.
l Calculation of the max. cable length:
First segment: 360 m
Second segment: 360 m (according to Tab. 5−1) minus 30 m (cable reduction when a repeater is used)
à Max. possible cable length with repeater: 690 m.
à Now the required cable length is possible.
) Note!
The use of a further repeater is recommended as a
ƒ Service interface
Advantage: Trouble−free connecting during ongoing bus operation is
possible.
ƒ Calibration interface
Advantage: Calibration/programming unit remains electrically isolated.