Welcome to LinuxCNC.org

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.

The sign of HOME_SEARCH_VEL in the ini file denotes the direction of travel for the first part of the homing.

http://www.linuxcnc.org/docview/html/config_ini_config.html#sub:[AXIS]-section

and

www.linuxcnc.org/docview/html/config_ini_homing.html

John

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...

Just curios why you would want the pwm signal all the time?

John

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.

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.

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.

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

I think I should increase the diameter of my leadscrews a bit, and I need to support them on both sides.


But it works

Looking good!

John