Cannot explain ferror? CNC hobbing machine
18 Sep 2017 15:58 #99090
by Diederik
Please explain how to do that? Or please direct me to documentation explaining how to do this? I'm busy learning more about components. (I've always only used ladder, and am now learning about components - I've always brushed it aside as it seemed complicated, but see the advantage.)
Replied by Diederik on topic Cannot explain ferror? CNC hobbing machine
take raw encoder counts as an input (S32) and internally promote that to S64, which can never wrap. Then calculate the workpiece position required from that in double-precision float.
Please explain how to do that? Or please direct me to documentation explaining how to do this? I'm busy learning more about components. (I've always only used ladder, and am now learning about components - I've always brushed it aside as it seemed complicated, but see the advantage.)
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19 Sep 2017 02:58 #99107
by andypugh
Replied by andypugh on topic Cannot explain ferror? CNC hobbing machine
Sorry, I am short of time at the moment (working away from home, in the US).
All your comp needs to do is add the spindle * factor to the A-axis input. Then you can jog, index and touch-off A.
It also needs to store a fixed offset, which is added to the current position and stored whenever the tooth count changes.
I use a G-code subroutine to perform the hobbing move, rather than use a component to move X and Y.
I made a custom (but rather untidy) GUI that also does basic gear dimension calculations.
wiki.linuxcnc.org/cgi-bin/wiki.pl?Hobbing
All your comp needs to do is add the spindle * factor to the A-axis input. Then you can jog, index and touch-off A.
It also needs to store a fixed offset, which is added to the current position and stored whenever the tooth count changes.
I use a G-code subroutine to perform the hobbing move, rather than use a component to move X and Y.
I made a custom (but rather untidy) GUI that also does basic gear dimension calculations.
wiki.linuxcnc.org/cgi-bin/wiki.pl?Hobbing
The following user(s) said Thank You: Diederik
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22 Nov 2017 10:58 #102179
by Henk
Replied by Henk on topic Cannot explain ferror? CNC hobbing machine
Hi All
Ok, after a couple of weeks tinkering with this config I seem to have solved the issue. I would like to do a lot more testing to make sure but so far so good. I created a comp that resets the encoder count of the spindle and the C-axis everytime the machine is set for a new job. the comp is still a bit crude and lacks some sanity checks etc but it seems to be working ok. See attached .comp.
One thing that I cant seem to implement is the use of the pin axis.n.f-errored. according to the man page, this pin should go high when a f-error occurs on that axis. I would like to use that to activate the hydraulic retract function for the x-axis. Linking this in Classicladder to the pin that activates the retract doesn't work for some reason. I have tried "netting" this pin in hal to halui.estop.activate with no result on f-error. I also tried using comparison blocks in classicladder (f-error>f-error-lim) to activate the retract but somehow this doesn't work either. I'm sure I'm missing something small. Any tips welcome
Thanks
Henk
Ok, after a couple of weeks tinkering with this config I seem to have solved the issue. I would like to do a lot more testing to make sure but so far so good. I created a comp that resets the encoder count of the spindle and the C-axis everytime the machine is set for a new job. the comp is still a bit crude and lacks some sanity checks etc but it seems to be working ok. See attached .comp.
One thing that I cant seem to implement is the use of the pin axis.n.f-errored. according to the man page, this pin should go high when a f-error occurs on that axis. I would like to use that to activate the hydraulic retract function for the x-axis. Linking this in Classicladder to the pin that activates the retract doesn't work for some reason. I have tried "netting" this pin in hal to halui.estop.activate with no result on f-error. I also tried using comparison blocks in classicladder (f-error>f-error-lim) to activate the retract but somehow this doesn't work either. I'm sure I'm missing something small. Any tips welcome
Thanks
Henk
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24 Nov 2017 18:08 #102305
by andypugh
Replied by andypugh on topic Cannot explain ferror? CNC hobbing machine
My experience is that f-errored is only set for a very short time.
You can probably stretch it to long enough for your purposes using the HAL oneshot component.
You can probably stretch it to long enough for your purposes using the HAL oneshot component.
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