Z axis cuts in the air - not plunging

Jeff65 wrote:

yeah switch is at the top

Ok on a fresh start of linuxcnc I think what you are saying is that when jogging Z before homing page down z goes down, then when you home its start going up to the switch then backs off it. But then you are saying that Z goes down with page up is that correct.

No -fresh start of Linuxcnc - before homing - page up makes it goes down
page down makes it go up.
After homing - same thing

Jeff65 wrote:

No -fresh start of Linuxcnc - before homing - page up makes it goes down
page down makes it go up.
After homing - same thing

But you said

At the moment the Z axis is moving the way it should - page up it goes up and page down it goes down and on the screen the same is apparent.

Its just when i try to home it goes off in the wrong direction

please just post the z section of the ini file

Z axis part of ini file

[AXIS_2]
TYPE = LINEAR
HOME = 0
MAX_VELOCITY = 12.5492060976
MAX_ACCELERATION = 13.0
STEPGEN_MAXACCEL = 16.25
SCALE = 2000.0
FERROR = 1
MIN_FERROR = .25
MIN_LIMIT = -75
MAX_LIMIT = 0.001
HOME_OFFSET = -2
HOME_SEARCH_VEL = -1.000000
HOME_LATCH_VEL = 0.050000
HOME_FINAL_VEL = 2
HOME_SEQUENCE = 0

Jeff65 wrote:

Z axis part of ini file

[AXIS_2]
TYPE = LINEAR
HOME = 0
MAX_VELOCITY = 12.5492060976
MAX_ACCELERATION = 13.0
STEPGEN_MAXACCEL = 16.25
SCALE = 2000.0
FERROR = 1
MIN_FERROR = .25
MIN_LIMIT = -75
MAX_LIMIT = 0.001
HOME_OFFSET = -2
HOME_SEARCH_VEL = -1.000000
HOME_LATCH_VEL = 0.050000
HOME_FINAL_VEL = 2
HOME_SEQUENCE = 0

Ok you have not changed what I suggested.

So start from scratch changed change the SCALE to -2000

save the file and restart linucnc then if the z goes up with page up that should be good.

If it does And when trying to home it moves in the wrong direction changed the sign here HOME_SEARCH_VEL = -1.000000

I know its frustrating but you will get there and have learnt what the things do in the ini file

Sorry - I can be a bit dim sometimes.

OK - I put a minus in front of the Scale setting - now if I press page up it goes up and if i press page down it goes down
However it is now reversed on the screen - goes down when you press page up - up when page down is pressed

Tried homing the axis and it goes in the wrong direction.
So I changed the sign in front of HOME_SEARCH_VEL
page up and down still worked fine but on screen was reversed.

It seemed to home ok - but cannot jog the axis down but it will go a little way up- screen problem still there

Jeff65 wrote:

Sorry - I can be a bit dim sometimes.

OK - I put a minus in front of the Scale setting - now if I press page up it goes up and if i press page down it goes down
However it is now reversed on the screen - goes down when you press page up - up when page down is pressed

Tried homing the axis and it goes in the wrong direction.
So I changed the sign in front of HOME_SEARCH_VEL
page up and down still worked fine but on screen was reversed.

It seemed to home ok - but cannot jog the axis down but it will go a little way up- screen problem still there

Ok not sure what to do about the screen BUT if it is not a pain I would change the SCALE sign back and reverse the motor wires.

You can do that on the drive just swap over either A or B but not both.

And see if the screen is ok

Also, don't use a negative value for home sequence. That is reserved for joint axes. eg. a gantry machine with 2 motors on one axis. Don't give up homing your machine as you start up. Its a very good habit to get into.

I have played about with settings many times and never got sorted - so I thought I would join this forum and I'm very grateful for your help.

I have already swopped wires on this stepper motor - I can swop them back

Would be happy to talk on the phone if you have the time

I would think its critical to have the screen match up with the motion otherwise I'll be cutting only air again

Jeff65 wrote:

I have played about with settings many times and never got sorted - so I thought I would join this forum and I'm very grateful for your help.

I have already swopped wires on this stepper motor - I can swop them back

Would be happy to talk on the phone if you have the time

I would think its critical to have the screen match up with the motion otherwise I'll be cutting only air again

++

I know you changed them before but we are starting again