DietmarJeske wrote:Not sure how familiar you are with TwinCat, but it provides Machine Control capabilities with sub msec response times.
This is prob. whats causing this, any idea what kind of polling its doing? serial, paralel?
Nothing to do with serial / parallel / or even USB - my virtual machine has all of these disabled.
I think the problem is to some extent inherent in what, and how, TwinCat does. Part of TwinCat runs as a service under Windows - in order to provide "real time" (i.e. deterministic) capabilities required for machine control functions. TwinCat will even remain operational if Windows "blue screens" - i.e. once installed, the TwinCat service pretty much operates outside of windows. On normal, real hardware, it will pre-empt windows to ensure that the machine control task gets the required amount of processor time.
Something about the way TwinCat does this, and how this is emulated in VirtualBox, don't mesh particularly well. It works, but consumes a lot of resources.
To be honest, I'm a little amazed that it works at all. Microsft Virtual PC doesn't work with it at all - have not tried any other virtualizers.