EtherCAT Function Blocks That Work With SDOs
ECATReadSDO and ECATWriteSDO are used to work with drive or remote I/O parameters that are not supported by ML and MC function blocks. Drive or remote I/O parameters that have an associated SDO number can be read and written using these function blocks.
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It takes more than one cycle to execute these function blocks (but less than 100 ms).
For more details about how to set up the update rate for SDO communication, refer to the FAQ
See some stats about the FB execution time
- There is a small difference in timing when running EtherCAT ***EtherCAT is an open, high-performance Ethernet-based fieldbus system. The development goal of EtherCAT was to apply Ethernet to automation applications which require short data update times (also called cycle times) with low communication jitter (for synchronization purposes) and low hardware costs at 2ms compared to other frequencies.
0.25, 0.5, 1ms 2ms Mean 9ms 14ms Min 3ms 8ms Max 16ms 24ms - Max time to consider when executing a single SDO command, (i.e. before the Done output becomes true): 24ms.
- Max time to consider when executing a single Drive Parameter command (i.e. before the Done output becomes True): 60 ms
4 kHz 1 kHz Mean 20 ms 11 ms Min 15 ms 9 ms Max 45 ms 58 ms - When sending multiple commands to a single drive, only one command can be sent at a time. Therefore the time to execute multiple commands is:
Number of commands x Execution time of a single command - When commands are sent to different AKD drives at the same time, the requests do not interfere with each other. So you can be confident the function finishes execution in the same max time as to one drive.
See also the FAQ to how to set up the update rate for SDO communication.
