A couple of things I would be looking at.
TwinCAT 2 or TwinCAT 3?
The CP2715 comes in 3 cpu options, the base single core, or various upgrades to dual, and even quad core cpu.
If you have Windows 10 32bit, and are running TwinCAT 2, you can only access a single core for TwinCAT related control (regardless of if you have a dual or quad core cpu). TwinCAT 2 is limited IIRC a max of 90% cpu allocation for TwinCAT Runtime usage. I believe default is 80% but it has been a few years since I touched TwinCAT.
You would want to check your PLC and Runtime execution times to see how much of your TwinCAT Runtime is being utilized for PLC tasks or SAF/SVB tasks for NC PTP or NC I motion axes. If you have a 1ms or less EtherCAT master update rate, and 4 axes of motion on a single core cpu, that can chew into your available CPU pretty fast depending on the overall size of your process image moving on the EtherCAT bus.
PLC tasks can chew up available RT too if you have some errant while/loops or other large processing delays.
Ultimately TwinCAT will service the Runtime system as a priority before relinquishing control back to windows for general UI, User mode applications, HMI etc. You cant really gauge how much the TwinCAT side is using by anything in Windows (i.e. taskman), you have to use the tools on the TwinCAT side to gauge load.
There are some alternative ways to balance the load if you have a Dual core, or Quad Core CPU in the CP2715 *AND* you have TwinCAT 3. With Multiple core cpu's and TwinCAT 3, you can take advantage of something called core-isolation. With Core isolation and dual core or greater cpu, you can hide one or more cores from windows, and direct TwinCAT to utilize only the isolated cores for all PLC and Realtime work. This would effectively leave windows free to run without the impact of TwinCAT on the remaining core(s) and would allow windows to be more responsive, and by proxy the applications (hmi, etc.) running on it.
Sorry this email is a little stream of consciousness I wanted to get some information out there to you while I was on break at work.
Kind Regards,
Patrick
