#linuxcnc-devel Logs

May 07 2018

#linuxcnc-devel Calendar

08:41 AM KimK: There are a lot of Python folks here. Anybody know anything about "R"? https://qz.com/1270139/r-and-python-are-joining-forces-in-the-most-ambitious-crossover-event-of-the-year-for-programmers/
08:53 AM KimK: There's this of course: https://en.wikipedia.org/wiki/R_(programming_language)
09:49 AM cradek: while I sympatize with those who are irritated by inconsistent indentation, it is my strongest possible opinion that running a reformatter on the code would make important things [merges, rebases, patches] much harder, and it only fixes trivial things that don't actually hurt us in any meaningful way.
04:27 PM mozmck: Spammers are getting more clever. One just pulled forum posts mostly asking linuxcnc questions from other places on the web and posted them on our forum with a couple of reference links. The first link is to the forum post from which the post is ripped, and the second was a spam link.
04:29 PM cradek: ugh.
04:30 PM mozmck: Yeah, a new user started 4 new topics like that. The first couple I saw looked fairly legit, but the next two made me wonder, then I followed the first links and found that the original posts were by different people altogether and were copied verbatim. The second links I think all went to the same place.
04:33 PM seb_kuzminsky: thanks for dealing with those jerks, mozmck
04:34 PM cradek: I hope the jerk spent more time on those than you did, but I bet not, sadly.
04:35 PM mozmck: Oh, no problem - and others do it as well! tommylight brought my attention to those by posting on the topics warning that the second link was advertising.
04:40 PM pcw_mesa: mozmck: You might be interested in a simple fix for following errors (apparent and real) caused by Ethernet packet loss: http://freeby.mesanet.com/pefix
04:40 PM mozmck: Yes, I might very well be! Thanks!
04:43 PM pcw_mesa: The problem is that if you lose a packet, both motion and the PID loop get stale position feedback data
04:43 PM pcw_mesa: this causes an apparent error from (velocity/servo-thread-time) and a real error because the PID loop
04:43 PM pcw_mesa: tries to correct for this apparent error
04:45 PM pcw_mesa: the fix is simple, just lie to motion and the PID by feeding them the commanded position as feedback if there's a packet error
04:45 PM mozmck: pcw_mesa: one thing I found with baytrail cpus was that I needed intel_idle.max_cstate=1 to prevent lockups on 4.1 and 3.18 I don't know for sure if it's needed in 4.16, but iirc it is needed.
04:46 PM pcw_mesa: Yeah I remember that, have not tried 4.16 on a Baytrail yet
04:46 PM mozmck: Thanks for that tidbit - I'll certainly implement that.
04:47 PM pcw_mesa: that fix also lets you set reasonable ferror limits even if you do lose a packet here or there
04:47 PM mozmck: Thanks a lot!
04:48 PM pcw_mesa: NP did for another cust, I was surprised how simple it was (thanks to hal)
04:53 PM pcw_mesa: http://freeby.mesanet.com/peduringslew.png
04:53 PM pcw_mesa: http://freeby.mesanet.com/fixedpe-slew.png
05:17 PM JT-Shop: pcw_mesa: what is a 7i76ED?
05:39 PM pcw_mesa: limp version?
05:41 PM pcw_mesa: The 7I76D,7I77D,7I76ED,7I84D are versions of the standard cards(no D) that have sinking outputs rather than sourcing
05:44 PM pcw_mesa: sometimes this is more convenient for retrofits (say wiring to relays that already have +24 common/flyback diodes already installed)
05:45 PM pcw_mesa: that is, the outputs of the D versions pull down to common/ground rather than pull up to +12/24
05:47 PM JT-Shop: thanks
05:47 PM andypugh: Why “D” and not “N” (for “NPN”) or I (for Inverted”) or L (for Low-side drive) ?
05:48 PM pcw_mesa: I just used D for down
05:50 PM JT-Shop: pcw_mesa: do you have the 7i76D and 7i77D in stock?
05:50 PM pcw_mesa: yes
05:50 PM JT-Shop: thanks
05:51 PM * JT-Shop goes back to the chicken yard for some chicken time
05:51 PM pcw_mesa: well some... didn't make a large number first time in case I mucked-up the artwork
05:52 PM JT-Shop: just want one each
05:52 PM JT-Shop: so I can say I have them in stock :)
05:53 PM pcw_mesa: yeah all 4 D version cards are available
08:09 PM Tom_L: "D" is a highly technical term
08:19 PM Tom_L: pcw_mesa, what was the 2nd line to add to the hal for ethernet cards?
08:20 PM Tom_L: can't seem to find it in the docs yet
08:30 PM Tom_L: or do i need both hostmot2 and hm2_eth loaded?
09:26 PM Tom_L: i think i got it.. nm