Performance Specifications - Dynacord P 64 Owner's Manual

Performance Specifications

According to the ISO 11898-2 standard, CAN-bus data transfer cabling has to be carried out
using Twisted-Pair cables with or without shielding providing a characteristic impedance of
120 Ω. Both ends of a CAN-bus need to be terminated with 120 Ω termination-plugs. The
maximum bus-length depends on the actual data transfer rate, the kind of data transfer cable
being used, as well as the total number of participants on the bus. The following table shows the
most essential requirements for CAN-networks consisting of up to 64 participants.
Resistance per
Bus Length (in m)
0...40
40...300
300 ... 600
600...1000
* With longer cables and many participants on the CAN-bus, termination resistors with higher
impedance than the specified 120 Ω are recommended to reduce the ohmic load of the interface
drivers and therefore the voltage drop between the two cable-ends.
The following table is meant for first assessment of necessary cable diameters for different bus
lengths and bus-participant numbers.
Bus Length (in m)
100 0,25 mm² bzw. AWG24
250 0,34 mm² bzw. AWG22
500 0,75 mm² bzw. AWG18
Additionally, the length of branch lines - for participants that are not directly connected to the
CAN-bus - is also of importance. For data transfer rates of up to 125 kbit/s, the maximum length
of a single stub cable should not exceed 2 meters. For higher bit rates a maximum length of only
0.3 meter is still permissible. The entire length of all branch lines should not exceed 30 meters.
General Note:
• As long as only short distances (up to 10 meters) are concerned, common RJ-45 patch
cables with a characteristic impedance of 100 Ω (AWG 24 / AWG 26) can be used for the
cabling inside of a rack mounted system.
• The previously outlined guidelines for network cabling are mandatory as far as the rack
mounted shelve interconnection or fixed installations are involved.
Date Transmission Cable
Cable Diameter
Unit Length
(in mΩ/m)
< 70 0,25...0,34 mm²
AWG23, AWG22
< 60 0,34...0,6 mm²
AWG22, AWG20
< 40 0,5...0,6 mm²
AWG 20
< 26 0,75...0,8 mm²
AWG 18
Number of Units on the CAN-Bus
32
Termination (in Ω)
124
127
150...300*
150...300*
64
0,34 mm² bzw. AWG22
0,5 mm² bzw. AWG20
0,75 mm² bzw. AWG18
Appendix
Max. Data Transfer
Rate
1000 kbit/s bei 40 m
500 kbit/s bei 100 m
100 kbit/s bei 500 m
62,5 kbit/s bei 1000 m
100
0,34 mm² bzw. AWG22
0,5 mm² bzw. AWG20
1,0 mm² bzw. AWG17
P 64 Digital Audio Matrix
Owner's manual
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