#linuxcnc-devel Logs

Jun 19 2019

01:09 AM Centurion-Dan2 is now known as Centurion_Dan
04:39 PM andypugh: pcw_mesa: pcw_home: What is the maximum number of encoders suported by hm2 on a single board?
04:40 PM pcw_mesa: umm...
04:41 PM andypugh: https://github.com/LinuxCNC/linuxcnc/issues/343
04:42 PM andypugh: I am wondering if a 32 bit bitmask is enough.
04:42 PM pcw_mesa: hardware does 64 max
04:42 PM pcw_mesa: not sure if the driver does or not
04:43 PM andypugh: I can’t see any limits in the driver
04:43 PM pcw_mesa: The quad error bug is fixed but only on my local copy...
04:43 PM andypugh: So, a 64-bit mask would work.
04:44 PM andypugh: I hadn’t realised how long this one has been about for.
04:44 PM andypugh: Seems hard to test…
04:45 PM pcw_mesa: Amit Goradia fixed it when visiting here last year
04:45 PM andypugh: I suppose I could connect an encoder with both A and B on the board connected to the A channel of the encoder?
04:45 PM pcw_mesa: yes that will generate an error
04:46 PM pcw_mesa: but firmware changes are needed also to avoid a race condition
04:46 PM andypugh: The fix you are talking about, is that driver-level or firmware-level?
04:48 PM andypugh: To see the bug I think I would need to be connected to encoder.2 ? So possiblya 7i76 connected to header 2 of a 7i80DB?
04:50 PM pcw_mesa: fix is both
04:50 PM pcw_mesa: Yeah i will have to make a current bitfile to test
04:54 PM andypugh: Maybe I should modify http://linuxcnc.org/docs/2.8/html/man/man9/sim_encoder.9.html to insert quadrature errors?
04:55 PM pcw_mesa: http://freeby.mesanet.com/0001-BUGFIX-hostmot2-encoder-quadrature-error-reporting-b.patch
04:56 PM pcw_mesa: http://freeby.mesanet.com/0001-Issue-394-BUGFIX-hm2-muxed-encoder-skew-drift-due-to.patch
04:56 PM andypugh: Ah, is that a tested and working patch?
04:57 PM pcw_mesa: yes both
04:57 PM andypugh: OK, I will just apply them both and close the issue then.
04:59 PM pcw_mesa: great
04:59 PM pcw_mesa: I figure its not an issue that requires a firmware revision # change and all the pain that will cause since the error reporting never really worked before
05:00 PM pcw_mesa: ( sure wish a major/minor firmware revision policy was decided on before HM2 was started... sigh )
05:07 PM andypugh: I giess it’s an integer?
05:08 PM andypugh: What is your highest-numbered firmware?
05:08 PM pcw_mesa: I think its a byte (2 nibbles would be enough) I thin 3 is the highest rev so far
05:09 PM andypugh: It might not be too late to start, just say that all current firmwares are 0.xxxx and for the next increment go to 8.xxxx
05:09 PM pcw_mesa: my theory would be that minor number are bugfixes and major require driver changes
05:09 PM andypugh: At the same time as we update the driver to ignore changes in the lower nibble
05:10 PM andypugh: (for values > 3 maybe)
05:11 PM pcw_mesa: I think there are only 2 modules with actual revisions
05:12 PM pcw_mesa: though obviously BISS needs one and i didn't change it
05:12 PM andypugh: Pity, that, it would have been handy to have been able to switch interpretations.
05:13 PM andypugh: PCW: https://github.com/LinuxCNC/linuxcnc/issues?q=is%3Aopen+assignee%3Aandypugh
05:13 PM andypugh: I have done all my other assignments.
05:14 PM pcw_mesa: Would it help if i hack the BISS code to add the new register and its bit fields?
05:15 PM andypugh: The firware you mean?
05:15 PM andypugh: Or the driver?
05:16 PM pcw_mesa: That reminds me I need to buy a BISS encoder on Ebay, last time I tested the code I borrowed a very expensive encoder from a customer
05:16 PM andypugh: As far as the driver goes, I have only really got as far as trawling my email archive for the email where you sent me the original regmap, so that I can see what it used to be, to see what needs to change.
05:17 PM andypugh: Renishaw posted me a Resolute. It got lost in the post :-(
05:17 PM pcw_mesa: I can hack at the driver the stuff tha needs to be decided is how to represent the added filter parameter
05:17 PM andypugh: (And with the encoder I also lost the trust of Renishaw)
05:18 PM andypugh: I am happy to do the driver fixes, it’s next on my list.
05:18 PM pcw_mesa: there are some motors with BISS encoders on Ebay for ~$200 and some encoder for ~$240
05:18 PM pcw_mesa: If you fix the driver, I can test
05:19 PM * pcw_mesa tabs to ebay
05:21 PM andypugh: pcw_home: Have you played with the STMBL at all?
05:21 PM andypugh: oops, wrong pcw..
05:22 PM pcw_mesa: No Are they available now?
05:22 PM andypugh: No BiSS for STMBL yet
05:22 PM andypugh: Not really.
05:22 PM andypugh: But I could send you one.
05:23 PM andypugh: They are working on a new design, not dependent on a particular driver form-factor.
05:23 PM andypugh: But I have 5 of the current design, and probably don’t need them all.
05:24 PM pcw_mesa: https://www.ebay.com/itm/Beckhoff-AM3021-1C41-0000-Servo-Motor/233230760899?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160811114145%26meid%3Dac830383b7dc401083d3298442984033%26pid%3D100667%26rk%3D4%26rkt%3D5%26sd%3D253990227211%26itm%3D233230760899&_trksid=p2045573.c100667.m2042
05:24 PM pcw_mesa: Motor with BISS encoder
05:24 PM andypugh: I could send you a broken one, I reckon you could fix it easier than I can.
05:24 PM pcw_mesa: that would be fine
05:25 PM andypugh: It’s brand new, not working from the PCBA house, something in the power supply stage on the HV board (LV board is good)
05:26 PM pcw_mesa: Yeah I can likely fix it
05:26 PM andypugh: I would imagine so, I am pretty sure I could :-)
05:27 PM pcw_mesa: just bought that motor so should have a BISS encoder in 10 days or so
05:28 PM pcw_mesa: Hope its not destroyed in shipping
05:29 PM andypugh: Something downstream of the ACT4088: https://imagebin.ca/v/4lBYaL9O5gzb
05:30 PM andypugh: I can throw in a spare ACT, I think
05:30 PM pcw_mesa: no 3.3V?
05:30 PM andypugh: Yes, exactly that
05:30 PM andypugh: Or is it no 15V? It’s been a while,
05:31 PM andypugh: I think that 15V is good, but 3.3 is not
05:31 PM pcw_mesa: usually I try to supply 3.3 with a lab supply to check for shorts
05:31 PM andypugh: I have enough good ones to have not got past “that’s broken”
05:32 PM pcw_mesa: slowly cranking up the current and checking for heat
05:33 PM andypugh: It’s coming back to me, that was the wrong schematic.
05:33 PM andypugh: It is the 15V that is bad.
05:33 PM andypugh: https://imagebin.ca/v/4lBZxZkkbYLr
05:34 PM andypugh: LNK304D is much more interesting that ACT4088
05:35 PM pcw_mesa: Yeah looks like an off-line supply
05:39 PM andypugh: yes, HV bus voltage to 15v