11-23-2005 01:08 PM
11-28-2005 11:47 PM
Hi Yen78,
Yes, the PID Auto Tuning vi increases the Kc gain parameter till system output becomes oscillatory. Page 2-6 of the manual http://digital.ni.com/manuals.nsf/websearch/A25258DF0D3E3CB386256B41000BA9B9 gives more information on this. You can also open the block diagram of the PID Auto Tuning vi and specifically look at the PID Relay Auto Tune.vi to see how the code is written. This tutorial has a section on Tuning which is also informative http://zone.ni.com/devzone/conceptd.nsf/webmain/d4748f0d59cf436d8625702700809ef4#3
Hope this helps!
Regards,
Prashanth
06-18-2006 02:28 PM
Hello,
I was hoping to get some insight on this vi.
I have the s/w and h/w set up and it is stable. So now we can attempt autotuning. We start the wizard, with the PV very close to SP, and do the noise thing and then we wait for three full cycles to get the OK to contunue. But... yesterday awaiting the three cycles we waited from 2:30PM to midnight - close to 10 hours. That's when I decided to stop it and start asking questions. Does this sound right?
Meanwhile the systems keeps close to the SP. The setup is a furnance control system.
Suggestions please?
Many thanks.