Three types of communication relationships:
1. Master/Slave relationship
2. Client/Server relationship
3. Producer/Consumer
以上三种模式彼此独立,不同协议采用不同模式对应。并且C/S需要应答机制保证数据传输的可靠性。即After finishing the task the server answers the request
The CANopen protocols comprise:
1. SDO protocol ——Service data objects
Enable access to all entries of a CANopen object dictionary
As these entries may contain data of arbitrary size and data type SDOs can be used to transfer multiple data sets (each containing an arbitrary large block of data) from a client to a server and vice versa
Direction of SDO:
a. write data to server using download
b. read data from server using upload
The indices of the corresponding Object
Dictionary entries are computed by the following formulas:
• SSDO communication parameter index = 1200h + SSDO-number -1
• CSDO communication parameter index = 1280h + CSDO-number -1
For
2. PDO