Rockwell Automation 20-COMM-K CANopen Adapter - Manual (Page 54)

6-2 Using Service Data Objects
20-COMM-K CANopen Adapter User Manual
Publication 20COMM-UM012B-EN-P
Running Service Data
Objects There are five basic events in the Service Data Objects process. The details
of each step will vary depending on the type of controller. Refer to the
documentation for your controller.
Important: There must be a request message and a response message for all
SDOs, whether you are reading or writing data.
Figure 6.1 Service Data Objects Process
CANopen DPI Parameter
Access An adapter parameter can be accessed by using the CANopen objects
0x2228 and 0x2229. The parameter request is written to object 0x2228.
When the acknowledgement is received, the response to the message is
placed in object 0x2229 and the response can be read.
Table 6.A Data Description for Object 0x2228 DPI Parameter Send
Table 6.B Data Description for Object 0x2229 DPI Parameter Receive
Event Description
➊
You format the required data and set up a PLC program to send an SDO request to the
CANopen network adapter (download).
➋
The CANopen network adapter transmits the SDO Request to the slave device over the
network.
➌
The slave device transmits the SDO Response back to the CANopen network. The data is
stored in the CANopen network buffer.
➍ The controller retrieves the SDO Response from the CANopen network’s buffer (upload).
➎ The SDO is complete.
➎
➊
➋ ➌
➍
Complete Service
Data Objects
Retrieve Service Data
Objects Response
Set up and send Service
Data Objects Request
Network
Sub Index Meaning Type
1 Parameter Access (00 = read, 01 = write byte,
02 = write word, 03 = write 32-bit word) Byte
2 DPI Port (0…6) Byte
3 Parameter Number 16-bit Word
4 Parameter value (for writing) 32-bit Word
Sub Index Meaning Type
1 Response Status:
0 = No Error
1 = Write only
2 = Value out of range
3 = Parameter does not exist
4 = Other error
Byte
2 Parameter value 32-bit Word