Home in place (no switch) and machine cordinate offset.

Hi
Working on a knee mill conversion from UCCNC to LinuxCNC. The knee is the Z axis. When I home, the knee is all the way down at a visual mark and the machine coordinate is set to 14.00. I’m trying to get the same thing to happen with Linuxcnc but can’t seem to make it happen. These are the settings I’m using:


MIN_LIMIT = 0.00
MAX_LIMIT = 14.00
HOME = 14.00
HOME_OFFSET = 14.00
HOME_SEARCH_VEL = 0
HOME_LATCH_VEL = -0
HOME_IGNORE_LIMITS = YES
HOME_SEQUENCE = 0

I have tried a lot of combinations of home and home offset. Swapping 0 and 14. -14 etc etc and no matter what the Z machine coordinate is always 0.00 when I click the home button.

Any advice?
Thanks.
Derek

 

Derek240 wrote:

Hi
Working on a knee mill conversion from UCCNC to LinuxCNC. The knee is the Z axis. When I home, the knee is all the way down at a visual mark and the machine coordinate is set to 14.00. I’m trying to get the same thing to happen with Linuxcnc but can’t seem to make it happen. These are the settings I’m using:


MIN_LIMIT = 0.00
MAX_LIMIT = 14.00
HOME = 14.00
HOME_OFFSET = 14.00
HOME_SEARCH_VEL = 0
HOME_LATCH_VEL = -0
HOME_IGNORE_LIMITS = YES
HOME_SEQUENCE = 0

I have tried a lot of combinations of home and home offset. Swapping 0 and 14. -14 etc etc and no matter what the Z machine coordinate is always 0.00 when I click the home button.

Any advice?
Thanks.
Derek

Are you saying that the you don't get any movement ?

if so:-
HOME_SEARCH_VEL = 0 this has to be a value
HOME_LATCH_VEL = -0 this has to be a value the -ve sign means it reverses

Hi Clive

No it's a home in place setup with no switches or movement.

MAX_LIMIT = 0
MIN_LIMIT= -14
HOME = 0
HOME_SEARCH_VELOCITY = 0

Should do what you want.

Hi Andy

I'm pretty sure that is what I'm doing now and yes it has the correct envelope but the machine coordinate with the knee down is 0.00 and I need it to be 14.00. I have a lot of code already with G53 G00 Z14.0 in it and I'd rather not have to edit all of it.

If you ever use Fusion360 that will put a G53 G0 Z0 at the start and end of each operation, that assumes that 0 is top.

If you want 14 at the top:

MAX_LIMIT = 14
MIN_LIMIT= 0
HOME = 14
HOME_SEARCH_VELOCITY = 0

<edit> Which is what you have. I don't think HOME_OFFSET matters with immediate homing but you could try setting that to zero.