On Sun, 16 Oct 2011, Tom Easterday wrote:
Date: Sun, 16 Oct 2011 10:45:34 -0400
From: Tom Easterday <tom-...@bgp.nu>
Reply-To: "Enhanced Machine Controller (EMC)"
<emc-users@lists.sourceforge.net>
To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net>
Subject: Re: [Emc-users] config without encoders
Well, apparently the problem didn't get resolved with the jog velocity vs
axis velocity thing….
Begin forwarded message:
From: Peter Jensen <jensen_rem...@yahoo.com>
Subject: Screenshots
Date: October 16, 2011 2:19:43 AM EDT
To: Tom Easterday <tom-...@bgp.nu>
Reply-To: Peter Jensen <jensen_rem...@yahoo.com>
Ok, you know how I said I fixed the problem? Well, apparently not. It's
doing it again.
One important thing to pay attention to is that the error is that the
reported "actual" position is getting AHEAD of the commanded position, and
then at the end of the move jumping BACK. All the moves in the images
below are from jogging in the positive direction on Axis 1. There are 4
images, taken with progressively faster jog speeds (you can see the jog
speed in the jog slider on the left hand window).
I am simply holding down the jog-positive key for a second or two, then
letting go. When I took these screen grabs, the motor power is off,
nothing is actually moving, and no encoder is actually connected to EMC.
If I turn on the motor power, the motors do move and can be seen to come to
the end of the jog and then move quickly back a fraction of an inch, just
as these following errors would indicate (and the hal-scope graphs are the
same - the motors being on or off has nothing to do with this, as there is
no encoder feedback connected to EMC or the mesa card).
Note that the Y axis scale of the following error is different in each image. As the
speed increases, the "following error" increases.
The scaling factor is 25464.79089470325 steps per inch, and the step length
and step space parameters are both set at 300 nano-seconds each (for a total of
600 nano-seconds per step). At 3600ipm there would be 654 nano-seconds between
steps, and this test topped out at only 3180ipm, so we should not be running
out of time.
So, there it is. Go figure. :)
--
Peter J. Jensen
Can you set the Stepgens maxaccel and maxvel to reasonable numbers?
Say 20% to 100% more than the machine limits for these numbers
Peter Wallace
Mesa Electronics
(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.
------------------------------------------------------------------------------
All the data continuously generated in your IT infrastructure contains a
definitive record of customers, application performance, security
threats, fraudulent activity and more. Splunk takes this data and makes
sense of it. Business sense. IT sense. Common sense.
http://p.sf.net/sfu/splunk-d2d-oct
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
