thanks Gene, My HAL Latency numbers are very good, jitter is about a third of your numbers, under reasonable video/network/OpenGL stress. I'm looking for a fast PCI or PCI-E parport card/chip family. The two NetMos i tried are dogs. I want to run the servo-thread at 5-10KHz to be able to sample pico's din pins faster for an engineering project.
On Thu, Mar 22, 2018 at 11:17 AM, Gene Heskett <[email protected]> wrote: > On Thursday 22 March 2018 09:45:49 Maxime Lemonnier wrote: > > > rt-preempt made no difference (well my HAL Latency Test are even > > better) > > > > Unplugging the second ppmc card cut the time roughly in half > > (expected) > > > > 22 s32 OUT 277802 ppmc.0.read.time > > 22 s32 OUT 194461 ppmc.0.write.time > > 16 s32 OUT 486932 servo-thread.time > > > > I conclude that the NetMos chips are just slow. sad. I can't even do > > 2KHz safely with these timings. > > I've come to theconclusion that amd cpu's are generally slower than > intel. And that generally speaking, Dell's are usually pretty decent. > Here are the relevant figures for the Dell I originally was going to use > to run the sheldon, until I got this wild hare and decided to use a > r-pi3b, that decision driven by the lack of sufficient i/o of a 5i25 > card even with bobs on both ports, whereas the $65 7i90HD has 72 gpio's. > > from its dmesg: > > CPU0: Intel(R) Pentium(R) 4 CPU 3.20GHz stepping 03 > > 2GB of dram. > > latency-test > servo-thread jitter 28072 period 994XXX > base-thread jitter 20649 period 246XXX > > bear in mind the base-thread isn't used by the mesa 5i25, so thats pretty > good, not the fastest, but plumb usable, and a similar machine is > running my G0704 mill. > > Finding a good parport, or even using the mobo's version, driving a > 7i90HD would give 72 gpio's, but comm time might be excessive enough to > cause ghost following errors. Not tried by me. The 7i90HD comes rigged > to talk to a parport, but the actual comm bandwidth by using the pi's > spi port, is I believe, faster. The spi firmware is installed with > mesaflash of course. > > The 5i25 seems to be able to stand more noise, but I will not say I've > not blown one as I have, poor frame grounding blew the pin I was using > as a probe input. > > The 7i90HD (both are 3.3 volt logic) seems to be easier damaged by > stepper motor noise pickup, so will need a 7i42TA for each one of the 3, > 50 pin ports as a noise and spike suppressor, which adds to the cost but > makes it bulletproof at the same time it also gives you a much much > better way to get things connected as it gives you the usual green > terminal strips for connections to the machine as opposed to trying to > keep jumper wires connected to the correct pins of a 50pin male socket. > Look at the cost of the 7i42TA's as the BoB's it doesn't need. > > Both the 5i25, and the 7i90HD have more than enough pwm's for machine > control. I don't know enough about the Pico board to comment. > > One other thing of note, anytime a pwm signal goes thru an opto-isolator, > anything resembling control linearity is lost. SainSmart is the only bob > currently for sale without the useless opto's in the output paths. > Inputs are still fed thru opto's on the SainSmart bob's, so I had to > remove the 2 used for encoder A/B inputs as they were waaaaayyyyyyy too > slow if the A/B signals are coming from the motor shaft, not the > spindle. > > > > On Thu, Mar 22, 2018 at 9:22 AM, Maxime Lemonnier < > > > > [email protected]> wrote: > > > Interesting, more in line with what I would expect. What lspci -vv > > > tells you about the chip on the PCI card? > > > > > > As I wrote you this morning I did try another PCI card I found: > > > > > > NetMos Technology PCI 9865 Multi-I/O Controller (prog-if 03 > > > [IEEE1284]) > > > > > > The PCI card is even worse: > > > > > > 10 s32 OUT 534652 ppmc.0.read.time > > > 10 s32 OUT 366536 ppmc.0.write.time > > > 8 s32 OUT 907936 servo-thread.time > > > > > > > > > Maybe I could try to boot in rt-preempt (using rtai right now) > > > > > > On Wed, Mar 21, 2018 at 9:46 PM, Jon Elson <[email protected]> > wrote: > > >> On 03/21/2018 03:15 PM, Maxime Lemonnier wrote: > > >> > > >> OK, I checked my system with a mediocre Dell Pentium 4 CPU and a > > >> PCI card, and ONE universal PWM controller. ppmc.0.write was 60 > > >> us, max was 95 us. > > >> ppmc.0.read was 128 us, max 188 us. > > >> The total thread was running 386 us. > > >> This is a Debian Wheezy system with the rt-preempt kernel. > > >> > > >> Jon > > >> > > >> ------------------------------------------------------------ > > >> ------------------ > > >> Check out the vibrant tech community on one of the world's most > > >> engaging tech sites, Slashdot.org! http://sdm.link/slashdot > > >> _______________________________________________ > > >> Emc-users mailing list > > >> [email protected] > > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > > ---------------------------------------------------------------------- > >-------- Check out the vibrant tech community on one of the world's > > most engaging tech sites, Slashdot.org! http://sdm.link/slashdot > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > -- > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > Genes Web page <http://geneslinuxbox.net:6309/gene> > > ------------------------------------------------------------ > ------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
