so on the first computer it scans at 135 useconds on a 1ms thread speed
and you could actually set it to a .2us thread speed?

on the second what is the scan time on a 1.1 ms thread speed?

I'm a little confused.
please clearly state the facts again and try to use the same unit so comparison 
is easier.
It hurts my head to compare micoseconds to nanoseconds to kilohertz.

:)

Chris M 

> Date: Mon, 6 Feb 2012 21:42:08 -0600
> From: [email protected]
> To: [email protected]
> Subject: Re: [Emc-users] Classic ladder questions and comments
> 
> Thanks for looking.  (I am not that technical though..)  The bit of 
> ladder I have seems to be taking longer than 1ms though. (on this 
> atom330 board)
> 
> sam
> 
> On 02/06/2012 06:02 PM, Chris Morley wrote:
> >
> >
> >>
> >>
> >> On Fri, 03 Feb 2012 13:05:02 -0600
> >>   sam sokolik<[email protected]>  wrote:
> >>> All this talk of lowering the servo thread had me thinking back to when
> >>> I was setting up the K&T.  I wanted to try to lower the servo thread for
> >>> testing.  I could not go much slower the the 1ms default or I would get
> >>> real time delays.  After some consultation on irc - it was decided that
> >>> the ladder was the issue.  I gave up and left my servo thread at 1ms.
> >>>
> >>> My ladder does tool chain logic, tool changing, pallet transfer and a
> >>> few other odds and ends.  It has probably over 16 sections and quite a
> >>> few rungs.  when the section display is open - the upper right hand
> >>> corner has the scan time - it is 135us.   vs the classic ladder sample
> >>> in the sample configs (pretty much just estop logic and oiling) which
> >>> runs in 17us.
> >>>
> >>> I have a older atom330 board here that I am playing with.  On a side
> >>> note - here is the latency test without isolcups=1
> >>> http://www.electronicsam.com/images/KandT/testing/atomnonisolcups.png
> >>>
> >>> with isolcups=1
> >>> http://www.electronicsam.com/images/KandT/testing/atomisolcpus.png
> >>>
> >>> I put the classic ladder parts into the emc stepper_inch config from the
> >>> sample configs (emc version 2.4.6) fresh install from the livecd then
> >>> updated.  I removed the base thread and stepgen functions from the 
> >>> threads.
> >>>
> >>> here is the config.
> >>> http://www.electronicsam.com/images/KandT/testing/stepper/
> >>> that has my ladder in it (just running - none of the pins are
> >>> connected)  This is ladder from sometime in the distant past - I am sure
> >>> it isn't the latest ladder.
> >>>
> >>> Now - on this atom - it will not run at 1ms.  It seems to run at
> >>> .909khz.  (servo period 1100000)  The K&T is using a asus motherboard
> >>> and amd processor.  (don't remember exactly but it is quite a bit more
> >>> powerful than the atom)  The atom board will run the sample ladder logic
> >>> down to about 5khz.
> >>>
> >>> So - the ladder isn't that intense - does classic ladder just take that
> >>> much time? Is there another issue?  am I making any sense?  :)  It seems
> >>> to me if I made a much larger ladder - it might stop running on the K&T
> >>> computer...
> >>>
> >>> sam
> >>>
> > from the source file module_hal.c:
> >
> > void HalWriteFloatOutputs(void) {
> >      int i;
> >      for( i=0; 
> > i<InfosGene->GeneralParams.SizesInfos.nbr_phys_float_outputs; i++) {
> >          *(hal_float_outputs[i]) = ReadVar(VAR_PHYS_FLOAT_OUTPUT, i);
> >      }
> > }
> > // This actually does the magic of periodic refresh of pins and
> > // calculations. This function runs at the period rate of the thread
> > // that you added it to.
> > // period, leftover, t0,and t1 are in nanoseconds.
> > // This function first checks to see if at least 1 millisecond has gone by
> > // if the period is under 1 MS then if will not refresh rungs yet but
> > // will keep track of how many NS were left over. Does this each period
> > // till at least 1 MS has occured, if more then 1 MS then keeps track of
> > // leftover NS for accuracy. Bottom line is you can run classiclader in
> > // a thread faster than 1 millisecond but it will not refresh the rungs
> > // any faster (it can be slower though). If your refresh is too slow and
> > // your timer are using multiples of 100 microseconds they might not be 
> > accurate.
> > // t0 and t1 are for keeping track of how long the refresh of sections,
> > // and HAL pins take (it is displayed in the 'section display' GUI (in 
> > microseconds).
> >
> > static void hal_task(void *arg, long period) {
> >      unsigned long t0, t1,milliseconds;
> >       static unsigned long leftover=0;
> >           leftover += period;
> >       milliseconds= leftover / 1000000;
> >      leftover %= 1000000;
> >
> >      if (milliseconds>= 1) {
> >      InfosGene->GeneralParams.PeriodicRefreshMilliSecs=milliseconds;
> >      *hal_state = InfosGene->LadderState;
> >      t0 = rtapi_get_time();
> >          if (InfosGene->LadderState==STATE_RUN)
> >              {
> >                  HalReadPhysicalInputs();
> >
> >                  HalReads32Inputs();
> >
> >                                  HalReadFloatInputs();
> >
> >                  ClassicLadder_RefreshAllSections();
> >
> >                  HalWritePhysicalOutputs();
> >
> >                  HalWrites32Outputs();
> >
> >                                  HalWriteFloatOutputs();
> >              }
> >            t1 = rtapi_get_time();
> >           InfosGene->DurationOfLastScan = t1 - t0;
> >                  }
> > }
> >
> > later the duration of scan (in nano seconds) is divide by 1000 to display 
> > micro seconds
> > which fit better in the display.
> >
> > I believe the idea of limiting the minimum refresh to 1 millisecond is so 
> > it is difficult
> > to set a refresh rate that is shorter then the duration rate.
> >
> > Maybe there is a better idea?
> >
> > Chris M
> >                                     
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