Brief Information About Canopen And Devicenet; Canopen (Controller Area Network) And Devicenet; Data Transmission; Bus Access For Subscribers - ABB AC500 Introduction Manual

Brief information about CANopen and DeviceNet

CANopen (Controller Area Network) and DeviceNet

The CANopen protocol was originally developed for the European automotive industry to replace
expensive cabling with an affordable system. Today, it is also used in the field of automation for
transmitting process data between control systems, decentralized I/O modules, drives, valves, etc. CAN
features a high level of transmission security, since large portions of the monitoring mechanisms have
been implemented directly in the CAN chip. DeviceNet and CANopen utilize the physical structure and
the data transport mechanisms of CAN (Controller Area Network). The difference lies in the transmission
protocols. DeviceNet and CANopen can be used correspondingly for the AC500 and AC31 controller
series and for field-bus-neutral FBP devices (decentralized I/Os and intelligent switching devices), via
the CANopen-FBP plug connector.

Data transmission

Two types of message have been defined: I/O data transfer and direct link. I/O data transfer is used for
time-critical process data, while the direct link can be, for example, used for diagnostic messages.

Bus access for subscribers

The connection ID with the lower address has higher priority on the bus. Data is transmitted by the
source, while the sinks (i.e. receivers of the data) have likewise been specified during the configuration
phase.
CANopen
The bus operates on the master/slave principle with one master and up to 127 slaves. A shielded
twisted-pair cable is used, according to ISO 11898. Cable lengths and transmission rates: from max. 40
m at 1 MBit/s to 1000 m at 20 kBit/s.
DeviceNet
The bus operates on the multi-master and/or the master/slave principle, with up to 64 bus subscribers.
Two types of shielded twisted-pair cables are used: trunk cable for the main line and drop cable for the
branch line.
Transmission rate
Max. cable length of
trunk line
Trunk cable
Max. cable length of
trunk line Drop cable
Max. cable length per
branch line
Trunk cable/Drop
cable
Max. cable length total
branch line
Trunk cable/Drop
cable
Diagnostics
Detailed diagnostic messages for rapid trouble-shooting are shown on the CPU display or can be called
using the programming tool. In addition, the device status is indicated at the communication module by
four LEDs.
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G1
Introduction to AC500
125 Kbit/s
500 m (1610 ft)
100 m (328 ft)
6 m (20 ft)
156 m (512 ft)
250 Kbit/s
250 m (820 ft)
100 m (328 ft)
6 m (20 ft)
78 m (256 ft)
1-10
500 Kbit/s
100 m (328 ft)
100 m (328 ft)
6 m (20 ft)
39 m (128 ft)
AC500 / Issued: 07.2006