CANopen
6
Parameter setting
6-2
L
BA2175 EN 2.0
6.1
Structure of a CAN data telegram
1 bit
11 bit
1 bit
6 bit
0 ... 8 byte
15 bit
1 bit
1 bit 1 bit
7 bit
Start
Identifier
RTR bit
Control field
User data
CRC sequence
CRC delimit.
ACK slot
ACK delimit.
End
Description in chapter 6.1.1
Three different data types are transported in this field:
•
Network management telegrams (NMT)
(Description in chapter 6.1.2 )
– NMT user data hold information about the communication structure via
CAN bus.
•
Parameter data (SDO)
(Description in chapter 6.2.1 )
– The user data are for parameter setting.
•
Process data (PDO)
(Description in chapter 6.3 )
– The process data in the user data are used for fast, mainly frequent
processes (e.g. speed setpoint and actual speed value).
•
Network management
•
Parameter data
•
Process data,
Fig. 6-1
Structure of a CAN data telegram
The data relevant for programming the bus module (identifiers and user data) will be described in
detail in the corresponding chapters.
All other signals refer to the transfer features of the CAN telegram. These Instructions do not
describe them in detail. For more information please see the homepage of “ CAN in Automation
(CiA)” : www.can-cia.de.
6.1.1
Identifiers
The CAN bus system is message-oriented. One of the most important components of a data
telegram is the identifier. Except for the network management (see chapter 6.1.2) and the sync
telegram (see chapter 6.3) the identier contains the controller address.
Identifier
=
basic identifier
+
controller address
With CANopen the controller address is used for a participant-oriented message addressing.
The identifier assignment is determined in the CANopen protocol. The basic identifier is default set
as described in the following:
Direction
Basic identifier
+ Controller
from the
controller
to the
controller
dec
hex
+ Controller
address
Network manager (NMT)
0
0
No
Sync telegram
128
80
No
Process data channel 1
X
384
180
Process data channel 1
X
512
200
Process data channel 2
X
640
280
Process data channel 2
X
768
300
Process data channel 3
X
896
380
Process data channel 3
X
1024
400
yes
Parameter data channel 1
X
1408
580
yes
Parameter data channel 1
X
1536
600
Parameter data channel 2
X
1472
5C0
Parameter data channel 2
X
1600
640
Node guarding
1792
700
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.actechdrives.com - Email: [email protected]
Show/Hide Bookmarks