Chris, I have tried all sorts of combinations of tuning. I set this to be the simplest and show what I am seeing. Nothing I have done has changed the general shape of the traces. I will see what I can do with your instructions. thanks Stuart
On Wed, Sep 15, 2010 at 9:26 AM, Chris Radek <ch...@timeguy.com> wrote: > On Wed, Sep 15, 2010 at 09:07:28AM -0500, Chris Radek wrote: > > > > It looks like the axes can't accelerate as fast as you are requesting. > > After looking at it again, this comment is wrong. > > > The problem is that your tuning is completely wrong for velocity > mode. With P only, you're commanding a velocity proportional to the > position error. This is not at all what you want. > > Setting this up is a little tricky. Your amps probably have their > gain set so that something around 9v is the rapid speed for the axis. > You need to set your ppmc dac scaling so a commanded rapid velocity > (in inches/second) gives this 9 volts. > > Looks like on ppmc, duty cycle = value / scale. So with value 8 > (rapid speed from your ini) if you want duty cycle 0.9 your scale > should be 8.89. > > Then you should set FF1 = 1 to make the pid output equal to the > commanded velocity (plus or minus the adjustments that will come > from P and D as you settle on a good tuning.) > > Once you have your scale set correctly you will get better following > but there will probably be a little steady following error that is > proportional to the velocity. You can adjust this by adjusting FF1, > scale, or (my preference) the tach gain knob on the amp. This will > fine tune that 9 volts to be your rapid speed. Everything else will > fall into place then. > > Chris > > > ------------------------------------------------------------------------------ > Start uncovering the many advantages of virtual appliances > and start using them to simplify application deployment and > accelerate your shift to cloud computing. > http://p.sf.net/sfu/novell-sfdev2dev > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- dos centavos ------------------------------------------------------------------------------ Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
