[etherlab-users] a puzzle about igh ethercat master

[殷士龙]

Hello, I am learning about the ethercat protocol and using igh ehtercat master, but have a puzzle.
I connected my slave and just start the igh master by using "ethercat start" command and no other user app run.
then I use wireshark to capture packet, result like the following picture:

I know it is scaning slaves all the time, but how about this FPRD datagrame, I haven't see any write cmd to set the slave position to the slave register。
so, this is my puzzle, I need some tips, thank you in advance!
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