This is a phenomenon that I have seen myself and with others. Texas instruments wrote an application note with this same issue. They noted with Codesys 3.5.19.10, that selecting CPU 1 as the EtherCAT task showed CPU spiking improvements over the performance of cores 0, 2, and 3. It appears to be linked to EtherCAT, are you configuring for use with distributed clocks? If so, I recommend choosing the 'Based on Input Reference' option. I have found it to reduce the CPU usage spike maximum slightly (see...
Hello, I encountered this same error. I was able to resolve it by allocating more messages when I open the network driver (ctMessages:= 100). By default it is set to 25.