Ambiguous EtherCAT Details -

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the following few introductory lines on ethercat:

the ethercat master sends telegram passes through each node. each ethercat slave device reads data addressed “on fly”, , inserts data in frame frame moving downstream.

my questions above text:

  • what reading data "on fly" mean?
  • how can data inserted in frame while moving? doesn't need copied first in buffer , updated?

this text taken http://www.ethercat.org/en/technology.html.

an ethercat network can compared railway each station can off-load , re-load train cars while train moves through station.

what reading data "on fly" mean?

it means reading happens @ same time when frame transmitting. it's pretty cut-through technology used switches. don't store whole received frame first, process it, , forward it. instead, read transmitting through "on fly" train passing through station.

how can data inserted in frame while moving? doesn't need copied first in buffer , updated?

the key these done slave's specific hardware(e.g., fpga, asic). hardware chip called ethercat slave controller (esc) in ethercat's parlance. esc guarantees "on fly" feature.

refer fabulous animation on youtube: ethercat functional principle.


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