Controller tuning problem in HYSYS

[naprirfan]

Hi my name is napz
i have a problem in using HYSYS. i'm dealing with PID controller and i can't get the oscillation graph.
the kc value for oscillation graph is between converges and diverges graph. the problem is when i set the appropriate kc, HYSYS is running for a few minutes seems like getting start to oscillate, but then there's always an error. the error message is equation failed to converge
does anybody knows why?
thx a lot

 

[MortenA]

maybe the occilations becomes so large that you get into a P/T area where the property package equations wont solve?

Best regards

Morten