Lenze ECSCExxx Power supply module - Manual (Page 148)

Appendix
General information about the system bus (CAN)
Structure of the CAN data telegram
12
l
148 EDBCSXE040 EN 7.0
Identifier
The identifier determines the priority of the message. Moreover, the following is coded:
ƒ The CAN node address (device address in the CAN network) of the node which is to
receive the CAN telegram.
See also chapter "Addressing of the parameter and process data objects" (
¶ 164).
ƒ The type of user data to be transferred
User data
The user data area of the CAN telegram either contains network management data,
process data or parameter data:
User data Description
Network management data
(NMT data) The information serves to establish communication via the CAN network
Process data
(PDO, Process Data Objects) l Process data are transmitted via the process data channel.
l The process data serve to control the controller.
l Process data can be accessed directly by the higher−level host system.
The data are, for instance, stored directly in the I/O area of the PLC. It is
necessary that the data can be exchanged between the host system
and the controller within the shortest time possible. In this connection,
small amounts of data can be transferred cyclically.
l Process data are transmitted between the higher−level host system and
the controllers to ensure a permanent exchange of current input and
output data.
l Process data are not stored in the controller.
l Process data are, for instance, setpoints and actual values.
Parameter data
(SDO, Service Data Objects) l Parameter data are transferred via the parameter data channel and
acknowledged by the receiver, i.e. the receiver gets a feedback whether
the transmission was successful.
l Parameter data of Lenze devices are called codes.
l The parameter data channel enables access to all Lenze codes and all
CANopen indexes.
l Parameters are set, for instance, for the initial commissioning of a
plant or when material of a production machine is exchanged.
l Usually the transfer of parameters is not time−critical.
l Parameter changes are stored in the controller.
l Parameter data are, for instance, operating parameters, diagnostic
information and motor data.
I
Tip!
The other signals refer to the transfer features of the CAN telegram that are
not described in these instructions.
For further information visit the homepage of the CAN user organisation CiA
(CAN in Automation): www.can−cia.org.