Ethercat

[Ballen22]

Hello all, Let's says my PLC has a refresh rate of 1 ms. Ethercat has a refresh rate of roughly 0.1ms. Correct me if I am wrong but every Plc scan time ethercat refreshes itself 10 times? Or does it only refresh itself one time with a time based on the Plc scan cycle of 1ms? Thank you

[Crossbow]

Depends on the controller I would think. I suspect it will only refresh the data once per PLC scan, but you can guarantee that new data was received in that length of time.

[CapinWinky]

EtherCat, ProfiNet, and Powerlink (and to a lesser extent Sercos III) are real-time, deterministic, ethernet protocols. They all have a cycle time and they refresh at that cycle time, every time, or they shut down with a major fault. Just because your PLC program isn't running as fast as them, doesn't mean that the EtherCat interface in the PLC isn't or that the drives you're connected to don't need to share position data faster than the PLC. I come from the B&R world where the drives do their own set point generation and function largely without interference from the PLC. It is very common to run electronic camming on Powerlink at 400microsecond cycle times so the master can send the slave it's position with a high resolution and fastest task on the PLC to be much slower at a few milliseconds cycle time.

[automationtechie]

We have a new series of EtherCAT compatible Remote IO modules. www.icpdas-usa.com/search-result-daq.php?Ethercat=Ethercat&submit=search