Operating instructions
14 08/06
4.6 Functional overview
The system bus produces the physical connection between the frequency inverters.
Logical communication channels are produced via this physical medium. These chan-
nels are defined via the identifiers. As CAN does not possess a subscriber-oriented, bu
t
a message-oriented addressing via the identifiers, the logical channels can be dis-
played via it.
In the basic state (factory settin
g
) the identifiers are set accordin
g
to the Predefined
Connection Set of CANopen. These settin
g
s are aimed at one master servin
g
all the
channels. In order to be able to build up process data movement via the PDO channels
between individual or a number of inverters (transverse movement), the settin
g
of the
identifiers in the subscribers has to be adapted.
Note: The exchange of data is done message-oriented. An frequency inverte
r
can transmit and receive a number of messa
g
es, identified via various
identifiers.
As a special feature, the properties of the CAN bus mean that the messages transmit-
ted by one subscriber can be received by a number of subscribers simultaneously. The
error monitorin
g
methods of the CAN bus result in the messa
g
e bein
g
re
j
ected by all
recipients and automatically transmitted again if there is a faulty reception in one re-
ceiver.
4.7 Network management
The network mana
g
ement controls the start of all the subscribers on the system bus.
Subscribers can be started or stopped individually or together. For subscriber recogni-
tion in a CAL or CANopen system, the slaves on the system bus generate a startin
g
telegram (boot-up report).
In the event of a fault. the slaves automatically transmit a fault report (emer
g
ency
message).
For the functions of the network management, the methods and NMT telegrams (net-
work management telegrams) defined according to CANopen (CiA DS 301) are used.
PLC
Controller / PC
Field bus
System bus Master
Parameter Function
SDO 2
SDO 1
PDO
System bus
System bus Slave
Parameter Function
SDO 2
SDO 1
PDO
System bus
System bus