Re: [Emc-developers] EtherCAT
On Wed, 27 Mar 2019, Chris Morley wrote:
Date: Wed, 27 Mar 2019 00:59:18 +
From: Chris Morley
Reply-To: EMC developers
To: EMC developers
Subject: Re: [Emc-developers] EtherCAT
I think adding docs would be a fine idea.
Chris M
Docs and perhaps some sample hal/ini files...
From: andy pugh
Sent: March 25, 2019 1:56 PM
To: EMC developers
Subject: [Emc-developers] EtherCAT
Whilst I think we have decided that it is not possible to distribute
an EtherCAT driver with LinuxCNC[1] it seems that some users are using
it extensively and successfully.
Which leads me to wonder if we should include a section in the
documentation about its use and where to download the enabling
software?
[1] Though where the license-break is is not clear:
Sascha's HAL driver is GPLv2:
https://github.com/sittner/linuxcnc-ethercat but I seem to recall that
actual use of EtherCAT involves an implied compliance with the
Beckhoff terms.
There is a summary here in an old machinekit discussion:
https://groups.google.com/forum/#!search/machinekit$20beckhoff/machinekit/yxQxqNbMvtc/UsaYVfAarCsJ
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916
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Re: [Emc-developers] EtherCAT
I think adding docs would be a fine idea. Chris M From: andy pugh Sent: March 25, 2019 1:56 PM To: EMC developers Subject: [Emc-developers] EtherCAT Whilst I think we have decided that it is not possible to distribute an EtherCAT driver with LinuxCNC[1] it seems that some users are using it extensively and successfully. Which leads me to wonder if we should include a section in the documentation about its use and where to download the enabling software? [1] Though where the license-break is is not clear: Sascha's HAL driver is GPLv2: https://github.com/sittner/linuxcnc-ethercat but I seem to recall that actual use of EtherCAT involves an implied compliance with the Beckhoff terms. There is a summary here in an old machinekit discussion: https://groups.google.com/forum/#!search/machinekit$20beckhoff/machinekit/yxQxqNbMvtc/UsaYVfAarCsJ -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1916 ___ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers ___ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
Re: [Emc-developers] Update-ini script
According to the note in 2.8 : http://linuxcnc.org/docs/devel/html/config/ini-homing.html#_home_sequence Not specifying the sequence at all will make it not respond to ALL Home Where as in 2.7 either not specifying it or setting it to -1 did the same. So it seems if you see -1 in a 2.7 config you must remove the line for it to be the same in a 2.8 config. Chris M From: andy pugh Sent: March 25, 2019 9:55 PM To: EMC developers Subject: [Emc-developers] Update-ini script I have just realised that the current (2.7) docs suggest a home-sequence value of -1 to disable homing of a joint. With JA in 2.8 that is no longer a particularly good idea. I think that the update-ini script needs to treat that situation specially. But what should it do? It's non-trivial in the current structure of the script to set home search velocity to zero in the INI if the sequence number is -1. But I think that is what I might need to do. Or would a number not-contiguous with the homing sequence have the same effect? -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1916 ___ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers ___ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
Re: [Emc-developers] Homing robot arm differential joint [ was robot arm, free to a good home]
On Tue, 26 Mar 2019 at 08:05, Frank Tkalcevic wrote: > > Thanks for the suggestion, but I don't think that will work. I need to move > both motors in the same direction to home the hinge part of the wrist. Then > I need to move the same motors in opposing directions to home the rotation of > the wrist. Only after both joints are homed can the motors be considered > homed. Maybe you can get round this with dummy joints. Make the motor positions the sum of two joints in HAL. Home Joint1 + Dummy2 then Dummy1 + Joint 2. Let the dummy joints hold a home offset but otherwise leave them unconnected to axes. (ie not mentioned in the kinematics) -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1916 ___ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
Re: [Emc-developers] Homing robot arm differential joint [ was robot arm, free to a good home]
Thanks for the suggestion, but I don't think that will work. I need to move both motors in the same direction to home the hinge part of the wrist. Then I need to move the same motors in opposing directions to home the rotation of the wrist. Only after both joints are homed can the motors be considered homed. I may be able to home the rotary part by sending the motors off in opposite directions, then I'll have to find another solution for hinge part. -Original Message- From: andy pugh [mailto:bodge...@gmail.com] Sent: Tuesday, 26 March 2019 8:18 AM To: EMC developers Subject: Re: [Emc-developers] Homing robot arm differential joint [ was robot arm, free to a good home] On Mon, 25 Mar 2019 at 21:10, Frank Tkalcevic wrote: > I'm not sure how to home these joints. To find the 2 home positions (bend > and rotate) requires moving both motors at the same time. That doesn't work > in joint mode homing as each motor/axis homes independently. If you give both motors the same homing sequence number then they will home at the same time. With v2.8 / Master if you give them the same _negative_ homing sequence number then each axis will "wait" for the other like is best for a gantry. That might suit your requirements. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." � George Fitch, Atlanta Constitution Newspaper, 1916 ___ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers ___ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
