Re: [CAD_CAM_EDM_DRO] Re: Lost Steps (Me again)

Low amps will magnify any resonance problems and create resonance problems
with step signals that are not perfectly timed.
EMC is a great servo program, but the stepper signals have a lot of jitter
in them. Until the jitter problem is fixed, EMC and steppers will not be
consistent. Some will work and other almost identical systems will not work.
Darrell
http://www.machinemaster.com

----- Original Message -----
From: <Ozzie@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: Tuesday, August 29, 2000 6:11 AM
Subject: [CAD_CAM_EDM_DRO] Re: Lost Steps (Me again)


> All,
> To add to the mystery:
> I had told Tim that these motors were 150 in-oz motors, (much smaller
> than his), but this morning I just recieved identification of the
> motors from the Italian manufacturer, saying that they are 474 in-oz,
> 90 Volts, 4 Amps!
>
> Tim's motor are 550's and he's running a 450mhz computer compared to
> my 200 mhz.
>
> Could my current be set too low? The Camtronics board is putting out
> 37 volts and set for 2.86 amps.
>
> Regarding the acceleration;
> I can try a lower number, but the problem occurs at low feeds, i.e.
> below 7ipm!
> Jerry
>
>
>
>
>
> --- In CAD_CAM_EDM_DRO@egroups.com, "Matt Shaver" <mshaver@e...>
> wrote:
> > > From: Tim Goldstein <timg@k...>
> > > The system he is using was set up with freqmod. It is a Pentium
> classic
> > 200.
> > > The period had to be set pretty high to get any reasonable
> responsiveness
> > > from the GUI. Following is the .ini file Jerry started with. Not
> sure of
> > any
> > > changes he made.
> > <...>
> > > ; Base task period, in seconds
> > > PERIOD = 0.000015
> >
> > This works out (if my math is right) to a PERIOD of 18 ticks of the
> CH0 clock
> > on the 8254 CTC. Gack! I was running 11 or 12 on my last machine
> and
> that was
> > with a 350MHz Pentium2.
> >
> > > [TASK]
> > > CYCLE_TIME = 0.010
> > > DEFAULT_VELOCITY = 0.1
> > > MAX_VELOCITY = 0.6
> > > DEFAULT_ACCELERATION = 6.0
> > > MAX_ACCELERATION = 6.0
> >
> > WOW! 6.0! Even 3.0, as Jerry said he reduced it to in his follow-up
> post, is
> > pretty high. I'm freaking out because I can't find a copy of the
> .ini file I
> > used for the BOSS Bridgeport I did, so I can't tell exactly what I
> used. I
> > think it was about 1.0, but I'm going to try and find that file...
> >
> > > [AXIS_0]
> > > MAX_VELOCITY = 0.3
> > > P = 1000.000
> >
> > You might try lowering P to 200 or so.
> >
> > > FF0 = 0.000
> >
> > You could also try adding FF0 gain if you lower P. I wish I had
> that
> file...
> >
> > > INPUT_SCALE = 8000 0
> > > OUTPUT_SCALE = 8000 0.000
> >
> > Oh boy :( My machine had a scale of 4000 and I couldn't get a
> velocity
> > greater than 0.9 reliably.
> >
> > > MIN_OUTPUT = -10
> > > MAX_OUTPUT = 10
> >
> > I also think I let the [TRAJ]MAX_VELOCITY stay at .9 and limited
> the
> axes
> > with MIN & MAX_OUTPUT, but that might not be necessary with the per
> axis
> > MAX_VELOCITY settings (that must be new...).
> >
> > I hadn't been following this thread closely, so I went back and
> read
> a bunch
> > of the posts. If this machine is a Shoptask just like Tim's, I
> wonder what
> > the difference is? Motors? PC? He's using the same Camtronics board
> as Tim.
> >
> > Does Jerry live anywhere near Maryland? Probably not... How about
> Colorado?
> >
> > This may be a problem soluble only with a faster PC, or an external
> step
> > pulse generator (I hope to have this in the not too distant
> future).
> Either
> > that or you'll have to stay with one of the other software packages
> that
> > freezes the GUI during moves to gain better control of the step
> pulse output
> > frequency stability.
> >
> > Matt
> >
> > P.S. I'll look for that file tomorrow, but I don't see why Tim's
> file
> > wouldn't work. Are you guys running the same OS and EMC versions?
>
>
>
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