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Negative home position seems to NOT work ???
22 Apr 2011 03:10 #9246
by kreature
Negative home position seems to NOT work ??? was created by kreature
I got my steppers set up on my homemade dirt-cheap cnc and I can jog everything around nicely.
My axis use the following home options:
X: -140 to +140mm, home at +140mm
Y: -80 to +80mm, home at -80mm
Z: 0 to 50mm, home at 50mm
X and Z homes fine, but Y starts homing the wrong way!
Y address is increasing while it attempts to home so I believe it looses the sign on the home address somewhere.
I am running a install from the ubuntu-10.04-linuxcnc1-i386 iso-file.
Looking at the ini-file it appears the stepconf wizard has done everything correctly and all my negative home addresses are there. Both in switch position and home position fields.
Can someone find out/verify if EMC2 has a bug regarding negative home address ?
I'm running in mm mode.
My axis use the following home options:
X: -140 to +140mm, home at +140mm
Y: -80 to +80mm, home at -80mm
Z: 0 to 50mm, home at 50mm
X and Z homes fine, but Y starts homing the wrong way!
Y address is increasing while it attempts to home so I believe it looses the sign on the home address somewhere.
I am running a install from the ubuntu-10.04-linuxcnc1-i386 iso-file.
Looking at the ini-file it appears the stepconf wizard has done everything correctly and all my negative home addresses are there. Both in switch position and home position fields.
Can someone find out/verify if EMC2 has a bug regarding negative home address ?
I'm running in mm mode.
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22 Apr 2011 10:53 - 22 Apr 2011 13:31 #9250
by BigJohnT
Replied by BigJohnT on topic Re:Negative home position seems to NOT work ???
The sign of HOME_SEARCH_VEL in the ini file denotes the direction of travel for the first part of the homing.
www.linuxcnc.org/docview/html/config_ini_config.html#sub:[AXIS]-section
and
www.linuxcnc.org/docview/html/config_ini_homing.html
John
www.linuxcnc.org/docview/html/config_ini_config.html#sub:[AXIS]-section
and
www.linuxcnc.org/docview/html/config_ini_homing.html
John
Last edit: 22 Apr 2011 13:31 by BigJohnT.
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22 Apr 2011 13:10 #9253
by kreature
Replied by kreature on topic Re:Negative home position seems to NOT work ???
Fantastic! Thanks.
Clever now that I know it, but not that intuitive.
Also a bit hard to actually find even though I did look several times.
Now I just need to get EMC2 to send a pwm signal all the time instead of just when spindle is on...
Clever now that I know it, but not that intuitive.
Also a bit hard to actually find even though I did look several times.
Now I just need to get EMC2 to send a pwm signal all the time instead of just when spindle is on...
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22 Apr 2011 13:33 #9255
by BigJohnT
Replied by BigJohnT on topic Re:Negative home position seems to NOT work ???
Just curios why you would want the pwm signal all the time?
John
John
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22 Apr 2011 15:35 #9257
by kreature
Replied by kreature on topic Re:Negative home position seems to NOT work ???
I am using a BLDC spindle which needs a constant 1ms duration pilot signal for "power off, but signal ok".
Typical RC stuff. 2ms pulses = full speed.
It uses governer mode with closed loop control so full speed is 22k rpm, with linear speed from 1.2 ms to 2ms with 1-1.2 being ignored due to it being too slow for controller to sync.
The motor itself is 1kW so it is strong enough. I used a different controller before, that I made myself and then I generated this signal internally. With EMC2 it would be nice if I could set it up to do all the controls.
If the signal is not there at all, the speed-controller disarms and requires a 1 second continous 1ms pulse train to rearm before acting on any higher pulse lengths and allowing motor to spool up.
Typical RC stuff. 2ms pulses = full speed.
It uses governer mode with closed loop control so full speed is 22k rpm, with linear speed from 1.2 ms to 2ms with 1-1.2 being ignored due to it being too slow for controller to sync.
The motor itself is 1kW so it is strong enough. I used a different controller before, that I made myself and then I generated this signal internally. With EMC2 it would be nice if I could set it up to do all the controls.
If the signal is not there at all, the speed-controller disarms and requires a 1 second continous 1ms pulse train to rearm before acting on any higher pulse lengths and allowing motor to spool up.
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22 Apr 2011 15:36 #9258
by kreature
Replied by kreature on topic Re:Negative home position seems to NOT work ???
I've heard the guys behind MicRo CNC is using bldc now too and for them this functionality would probably be welcome as right now they control spindle speed manually.
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22 Apr 2011 23:09 #9273
by kreature
Replied by kreature on topic Re:Negative home position seems to NOT work ???
I found a quick workaround for now to the spindle issue.
Adding:
s1 m3
g4 p1
s6000
g4 p2
Seems to allow the controller to rearm as the signal "comes back" and since 1 rpm is in the deadzone it's ignored and treated as a valid 0 rpm arming signal.
Then the rpm can be increased and a short delay is smart to let it spool up.
Adding:
s1 m3
g4 p1
s6000
g4 p2
Seems to allow the controller to rearm as the signal "comes back" and since 1 rpm is in the deadzone it's ignored and treated as a valid 0 rpm arming signal.
Then the rpm can be increased and a short delay is smart to let it spool up.
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22 Apr 2011 23:32 #9275
by BigJohnT
Replied by BigJohnT on topic Re:Negative home position seems to NOT work ???
I have to do a trick like that on my BP 308 VMC... a bunch of sxxx with a short g4 between as the caps are shot on the power supply and won't take s6000 from a dead start.
Glad you got it sorted out for now.
John
Glad you got it sorted out for now.
John
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23 Apr 2011 10:18 #9278
by kreature
Replied by kreature on topic Re:Negative home position seems to NOT work ???
I think I should increase the diameter of my leadscrews a bit, and I need to support them on both sides.
But it works
But it works
![:) :)](/media/kunena/emoticons/smile.png)
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23 Apr 2011 10:56 #9279
by BigJohnT
Replied by BigJohnT on topic Re:Negative home position seems to NOT work ???
Looking good!
John
John
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- Configuring LinuxCNC
- Configuration Tools
- StepConf Wizard
- Negative home position seems to NOT work ???
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