CANopen Firmware
CAN-CBX-DIO8
Manual • Doc.-No.: C.3010.21 / Rev. 3.1
Seite 47 von 123
8.4 Communication Parameters of the PDOs
The communication parameters of the PDOs (according to [1]) are transmitted as SDO (Service
Data Objects) on ID ‘600
h
+ Node-ID’ (Request). The receiver acknowledges the parameters on ID
‘580
h
+ Node-ID’ (Response).
The Node-ID (module No.) is configured via coding switches Low and High. Please refer to chapter
“Coding Switches” (page 19) for a detailed description of possible configurations.
8.4.1 Accessing the Communication Parameters via SDO Telegrams
The SDOs (Service Data Objects) are used to access the object directory of a device.
An SDO is therefore a ‘channel’ to access the parameters of the CAN-CBX-module. Access via this
channel is possible in operational and pre-operational status in the CAN-CBX-module.
This chapter does not describe all possible, but only some important modes of access in the CAN-
CBX- module.
Definitions for the access modes can be taken from [1].
An SDO is structured as follows:
Identifier
Command
code
Index
Sub-index
LSB
Data field
MSB
(low)
(high)
Example:
600
h
+
Node-ID
23
h
00
14
h
01
7F
h
04
h
00
00
(write)
(Index=1400
h
)
(Receive-PDO-Comm-Para)
(COB-def.)
COB Node ID = 0000 047F
h
Identifier
The parameters are transmitted with ID ‘600
h
+ NodeID’ (request).
The receiver acknowledges the parameters with ID ‘580
h
+ NodeID’ (response).
Command code
The command code transmitted consists among other things of the Command Specifier and the
length. Frequently required combinations are, for instance:
40
h
= 64
dec
:
Read Request, i.e. a parameter is to be read
23
h
= 35
dec
:
Write Request with 32-bit data, i.e. a parameter is to be set
The CAN-CBX-module responds to every received telegram with a response telegram. This can
