Homing new build cnc plasma table

Hi all,

I have just built a cnc plasma table and am having issues with homing it correctly. I built a config using the 7i96 config tool. It would home all axis but once homing was completed, i could only move the axis between the limit switch and home offset position not the full width of the table. I managed to over come this by putting a - on the home_search_vel, which moved the home positions and the x + y axis now seem to work ok, but it doesn't work for the z axis as it needs to home at the max limit.

Before i altered the home_search_vel the machine would home to the right on the x axis and furthest away on the y axis, which seems incorrect compared to where 0,0,0 is on linuxcnc. When i jog all the axis they move the correct way compared to what linuxcnc thinks.

Why would it be homing in the opposite direction to what it should be on the x+y axis?

And how do i overcome the z axis not being able to move past the home offset position once homed?

This is what the unaltered ini file shows -

HOME = 0
HOME_OFFSET = 5
HOME_SEARCH_VEL = 5
HOME_LATCH_VEL = 1

I've changed the ini file to this for x+y axis - (it seems to work but i don't think its correct)

HOME = 5
HOME_OFFSET = 0
HOME_SEARCH_VEL = -5
HOME_LATCH_VEL = 1

Any ideas?

Thanks,
Pete

FIND ATTACHED

That all sounds normal, If your home/limit switch is at the negative end of travel (left side for X and front/closest for Y) your search velocity setting should be negative. For your Z axis since the home/limit switch is at the top/positive end it's search velocity should be positive.

Ok, once they are homed the z axis won’t lower. It will only move between the limit switch and home offset. Any ideas?

PeteJM wrote:

Ok, once they are homed the z axis won’t lower. It will only move between the limit switch and home offset. Any ideas?

Re :-

[JOINT_3]
AXIS = Z
MIN_LIMIT = 0
MAX_LIMIT = 170 Try -170

It is more normal for the Z axis to be -ve going down.

Thanks changing to negative has solved that. Tested it and all was working well. but i have run the plasmaC config and now the homing and limit switches have stopped working. I have opened the hal meter and a signal is being received from the switches.

Anyone got a solution? i have attached the ini and hal files

Homing sequence for dual motors in the ini file you need both to be the same number and -ve

ie HOME_SEQUENCE = 1 should be -1 for both. Also you need to use home-all and not use jog until they are homed

Thanks will change that. When I press home all, the x axis drives to the home switch and doesn’t stop moving in that direction and hits the stops. it’s like the home switch is not working but it does send a signal in Hal meter. It’s the same in all axis. It worked perfectly before I loaded the plasmac config.
Any idea?