Reading etherCAT sensor readings in FPGA project

[nottilie]

Sorry i expected 2kHz but you need 20kht so the task cycle time of the PLC needs to be at least 50µs. It is not clear if your PLC is powerful enough to manage this time and I also think that the standard Beckhoff Terminal is by far not able to  convert the data with this frequency, but propably i am wrong.

I just saw the specifications for nomal Beckhoff AI terminals. See attachment.

[rolfk]

I kind of doubt you can do 50us cycle time in a TwinCAT program executed on any CPU even if you do little more than just read in the EtherCAT sensor and store it somewhere in a buffer with maintaining the read and write pointers into the buffer. The other question is if you even can do 20kHz cycle time on the EtherCAT bus. EtherCAT is designed for determinisme not high speed data transfer and that involves some overhead in the EtherCAT data train on the bus! Better would be a device that can define its own sampling time and transfer data in blocks at a lower speed than sample by sample.