Thanks Andy and Kirk. I think there's nothing activated on the VFD by now, the last whing was the acceleration.
About what you say andy, this VFD it's capable of handle a smooth turn without load at 1 hz, but I don't know what's going to happen when the motor is attached to the screw. I will try tomorrow with your advice of using more following error and try to eliminate the oscilation. I thought it was tricky this way because without the screw all the inertia has to be stopped without help. When it's connected to the screw it will behave a lot different, I'll be ataching the motor in the next days because I'm finishing the mechanical adaptation for the encoder. 2013/12/4 andy pugh <bodge...@gmail.com> > On 4 December 2013 22:19, Leonardo Marsaglia > <leonardomarsagli...@gmail.com> wrote: > > > I managed to move the motor and do some tests but I can't get rid of the > > oscillation from the PID. If I follow the classic way of tunning the > > algorithm when I increment P I don't see any oscillation until I disturb > > the motor. When that happens I get a really strong vibration and right > > after that a following error. What I'm saying is I can't even start to > test > > my error to decrease it. > > Firstly I would set the folllowing error to about 16, two full turns. > (if you get more than that, then you probably do want to stop). > > Then see if you can kill the oscillation with some D term. > > Tuning a bare motor is often hard even when it is a real servo, and an > induction motor is likely to be worse. > > One problem you are likely to have, and which I had, was that my VFD > didn't do anything at all unless the frequency demand was more than > 5Hz. > The solution to this might be some sort of inverse deadband, so that > even a small velocity demand is at least 5Hz. (1V to the VFD or > thereabouts) > > One way to do this, with a fair bit of tunability is with the > "lincurve" HAL component. You could set that up to give no output with > +/- 0.1V demand, 1V with >0.1V demand with X = -10, -0.1. -0.1, +0.1, > +0.1 +10 and Y = -10, -1, 0, 0, 1, 10. > > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > > ------------------------------------------------------------------------------ > Sponsored by Intel(R) XDK > Develop, test and display web and hybrid apps with a single code base. > Download it for free now! > > http://pubads.g.doubleclick.net/gampad/clk?id=111408631&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- *Leonardo Marsaglia*. ------------------------------------------------------------------------------ Sponsored by Intel(R) XDK Develop, test and display web and hybrid apps with a single code base. Download it for free now! http://pubads.g.doubleclick.net/gampad/clk?id=111408631&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
