EtherCAT Function Blocks that Work with SDOs
ECATReadSdo, ECATReadSdoData, ECATWriteSdo, and ECATWriteSdoData 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).
See When can I expect my SDO command to be completed? in the FAQs on how to set up the update rate for SDO communication.
Stats about the FB Execution Time
- There is a small difference in timing when running EtherCAT 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.
- The time to execute multiple commands is:
Number of commands x Execution time of a single command
- The time to execute multiple commands is:
- When commands are sent to different AKD drives at the same time, the requests do not interfere with each other.
- The function finishes execution in the same maximum time as one drive.
