The control loop starts with the TX/RX handled by Ethercrab. It sends the EtherCat frome to all devices and waits for recieval. Although EtherCAT supports multiple in-flight frames we just use one at a time.
We loop over every device and check if the inputs for this device match the expected length (byte length).
If the size matches we give the inputs to the TxPdo object of the device which will decode and store the inputs.
We loop over all known actors and call their act function. This is where the control loop logic happens. They can read the input and write the output.
We loop over every device and check if the outputs for this device match the expected length (byte length).
If the size matches we give the outputs to the RxPdo object of the device which will encode the outputs.