#emc-devel | Logs for 2007-04-08

[01:14:14] <cradek> petev: I tried, but cannot catch an accel constraint violation.
[01:56:50] <petev> cradek, what was yuur test case?
[01:57:14] <petev> I'm not convinced I have a handle on all the different scaling and what will actually show up in the HAL yet
[01:57:23] <cradek> lots of test cases
[01:57:45] <petev> was the feed at max velocity when the decel started?
[01:57:46] <cradek> you should test without me telling you how to do it
[01:58:09] <petev> I know what the test case should be, but it's not clear to me what actually shows up in HAL
[01:58:25] <petev> there is too much scaling going on in different places
[01:58:48] <jmkasunich> hal position commands are in machine units
[01:59:03] <petev> did u see signals that looked like they had the right values for velocity, etc.
[01:59:08] <jmkasunich> run it thru 2 ddt blocks and you get velocity in machine units/sec and accel in machine units/sec^2
[01:59:14] <jmkasunich> which are the same as the units in the inifile
[01:59:17] <cradek> sim has the ddt set up already
[01:59:38] <petev> ok, I'll try and take a look at it
[02:53:56] <petev> u guys there?
[02:54:37] <petev> jmkasunich, cradek
[03:10:07] <jmkasunich> not me, I'm not here at all
[03:11:56] <petev> ok, I got a voliation on the first test case
[03:12:12] <petev> also, the accel waveforms look rather deformed from what I expected
[03:12:27] <jmkasunich> screenshot on imagebin?
[03:12:41] <petev> ok, hang on
[03:12:53] <petev> hmm, it's very big uncompressed
[03:12:59] <petev> how about I email it
[03:13:00] <jmkasunich> png?
[03:13:03] <petev> bmp
[03:13:10] <jmkasunich> wtf is bmp!
[03:13:21] <petev> I'm on a doze box
[03:13:26] <petev> it's a straight bitmap
[03:13:34] <jmkasunich> I know - thats why I'm giving you a hard time
[03:13:53] <jmkasunich> you can't do a "save as" .gif or .png?
[03:14:04] <petev> let me see
[03:14:14] <jmkasunich> bmp: bloated mega pixels ;-)
[03:14:33] <petev> no, all I have is the crappy MS paint program and it won't do it
[03:14:43] <jmkasunich> you need gimp
[03:14:59] <petev> email on it's way
[03:15:18] <petev> all I did is calc the raduis that should cause the problem from the values in the INI
[03:15:18] <jmkasunich> http://www.gimp.org/windows/
[03:15:28] <jmkasunich> a real image editor
[03:15:29] <petev> then I ran it and it was there
[03:15:34] <petev> yeah, yeah
[03:15:41] <petev> I don't do graphics ;-)
[03:16:03] <jmkasunich> I'm serious - gimp is nice, there is an easy windows install, whats not to like?
[03:16:30] <petev> I expected the accel to look like a square wave with trapezoidal velocity, but it's quite distorted
[03:16:36] <petev> what do you think is going on there?
[03:16:45] <jmkasunich> I dunno about the windows version, but my gimp has File->Acquire->Screenshot, lets me capture the whole screen or a window - very convenient
[03:17:25] <jmkasunich> ok, what is your accel limit?
[03:17:27] <petev> if my monitor wasn't out on the mill, I would run it on the linux box
[03:17:36] <petev> but as it is, I'm using X from doze
[03:17:46] <petev> straight from servo_sim.ini
[03:17:49] <petev> accel is 20
[03:17:53] <petev> vel is 1.5
[03:18:03] <jmkasunich> so you are hitting the accel limit at the bottom
[03:18:14] <SWPadnos> imagemagick is available for Windows
[03:18:16] <petev> I calc the test case for the default sim INI file
[03:18:34] <petev> did u get the email yet?
[03:18:44] <jmkasunich> yeah, I'm looking at the pic
[03:19:36] <petev> for a circle, shouldn't the accels be sin and cos?
[03:19:42] <jmkasunich> thats a 90 degree arc?
[03:19:45] <petev> why are they so distorted
[03:20:00] <petev> or is that due to the tangential acell/decell ?
[03:20:03] <jmkasunich> yeah, it will be distorted by the initial accel and the final decel (tangential)
[03:20:08] <petev> no, look at the G-cod
[03:20:11] <petev> 73 degrees
[03:20:33] <petev> takes about 28.6 degrees for accel and decel portions
[03:20:33] <jmkasunich> if you say so (I don't read g-code arcs that well - remember, I do low level stuff)
[03:20:37] <petev> the rest is cruise
[03:20:49] <jmkasunich> you'll only have the nice sin/cos during cruise
[03:21:08] <petev> ok, I can buy that
[03:21:10] <jmkasunich> and with a 73 degree total, and 57 degrees used up in accel and decel, you ain't got much cruise
[03:21:30] <petev> true, but I wanted to start decel near 45 degrees
[03:22:15] <jmkasunich> next time do 163 degrees
[03:22:37] <jmkasunich> that will get you a cruise segment long enough to get your bearings from
[03:23:31] <jmkasunich> oh, another distortion source is just time
[03:24:21] <jmkasunich> it takes about three times as long to do the first 28 degrees as it does to do the 16 degree cruise portion
[03:24:36] <cradek> your traj velocity is less than your axis velocity
[03:24:50] <cradek> I made mine higher so the axis vel would limit it
[03:25:00] <petev> yeah, I saw that, but that's the default file
[03:25:28] <cradek> yuck
[03:25:37] <cradek> some of our default files are not great
[03:25:43] <jmkasunich> if the axis limits are 20, then regardless of what the traj limit is, the -22ish value that he's seing is a violation
[03:25:51] <petev> true
[03:25:52] <cradek> sure
[03:27:37] <cradek> if you use g64 does it go away?
[03:27:49] <jmkasunich> I wish there was a longer cruise portion, I'm having trouble correlating the traces to the move
[03:27:54] <cradek> I didn't think of trying g61 but I bet that's the key to triggering it
[03:28:03] <petev> don't know, I wanted exact path, but it really shouldn't matter with a single arc
[03:28:08] <jmkasunich> those are blending codes?
[03:28:21] <cradek> do a semicircle plus this
[03:28:57] <petev> how about we put in the cos(45) factor and run the same test again?
[03:29:05] <petev> I bet it won't violate
[03:29:18] <cradek> sure that's fine
[03:30:20] <jmkasunich> it would be interesting to add a hypot component there, to get the total accel
[03:30:57] <cradek> sim may have those already
[03:31:15] <jmkasunich> I suppose I should fire it up... but I'd rather work on vhdl
[16:42:59] <alex_joni> ( 2007-04-07 18:57:24 - Project CVS Service ) On 2007-04-07, the CVS server for project letters m, n, and q has a disk problem that has caused a lapse in service. We are working to repair this.
[16:44:00] <cradek> their notices always remind me of sesame street
[16:45:30] <alex_joni> how so?
[16:46:41] <cradek> today's sesame street was brought to you by the letters w, n, and z, and the number 3
[16:52:12] <alex_joni> hmm.. maybe if I would watch I might get it..
[16:52:23] <alex_joni> but we didn't have it around here..
[18:59:14] <skunkworks> :)
[21:59:21] <alex_joni> cradek: seems vmware server now supports SMP
[21:59:37] <alex_joni> if the host has 2 processors, it can provide those to the guest too..
[21:59:46] <alex_joni> I might give rtai & SMP another go
[22:00:08] <alex_joni> (although I'm not sure how much this would prove..)