Ac And Dc Parameters For The Canopen Network; Bus Cable And Termination Resistors - ABB FCAN-01 User Manual

34 Electrical installation

AC and DC parameters for the CANopen network



Bus cable and termination resistors

The cables, connectors, and termination resistors used in
CANopen networks must meet the requirements specified in ISO
11898.
The table below lists the standard values for DC parameters for
CANopen networks with less than 64 nodes:
Bus length
[m]
Length-
related
resistance
[mohm/m]
0...40 70
40...300 < 60
300...600 < 40
600...1000 < 26
1)
Recommended cable for AC parameters: 120 ohm impedance and 5 ns/m line delay
With drop cables the recommended cable cross-section is
2
0.25...0.34 mm
In addition to the cable resistance, the real resistance of the
connectors should be taken into account in voltage drop
calculation. The transmission resistance of one connector should
be 2.5...10 mohm.
The following table lists the maximum bus cable length for different
node numbers (n), when
•
minimum dominant value V
•
minimum differential input resistance R
•
requested differential input voltage V
•
minimum termination resistance R
1)
Bus cable
Cross-
section
2
[mm
0.25...0.34
0.34...0.6
0.5...0.6
0.75...0.8
.
diff.out.min
Termination
resistance
[ohm]
]
124
150...300
150...300
150...300
= 1.5 V
diff.min
= 1.0 V
th.max
= 118 ohm.
T.min
Baud rate
[kbit/s]
1000 at 40 m
> 500 at 100 m
> 100 at 500 m
> 50 at 1 km
= 20 kohm