Homing / limits - the manual is misleading, possibly wrong

Yes I see what you are saying now. I agree with you.

Hmm now I'm wondering if even machine origin needs to be inside soft limits.
I'm not seeing why you can set soft limits to something like
min = -100
max = -1

If we are going to change the docs, might as well get it all right.
I''ll have to experiment.
Thanks

After some experimenting in a sim, I could in fact have a config that had soft limits between 1 and 440
home offset was .5
shared limits and home switch

I'll digest the information and try to update the docs to something true and understandable...

Chris

I think HOME (the final position of the axis at the end of homing) must be within the soft limits.

The numbers seem to be arbitrary / flexible, however I can't think of why someone would want to set up an axis that did not include zero. Would make GCode programming a hassle.

I think the docs might need two setups explained:
Shared home/limit switch
Separate home and limit switches

The numbers seem to be arbitrary / flexible, however I can't think of why someone would want to set up an axis that did not include zero. Would make GCode programming a hassle.

It's machine coordinates so only accessed by G53 not a usual way to program. Zero point is arbitrary so not having one is arbitrary too, though i agree having zero inside the soft limits and having all positive soft limits is probably the best.

yes Home position must be inside soft limits.

Chris

cmorley wrote:

The numbers seem to be arbitrary / flexible, however I can't think of why someone would want to set up an axis that did not include zero. Would make GCode programming a hassle.

It's machine coordinates so only accessed by G53 not a usual way to program. Zero point is arbitrary so not having one is arbitrary too, though i agree having zero inside the soft limits and having all positive soft limits is probably the best.

yes Home position must be inside soft limits.

Chris

I have come across post processors that insert a G53 Z0 for manual tool changes or at the end of programs.

Sure I could see that. but the choice of zero is arbitrary.
As the integrator you get to decide and you must change your post processor to accommodate.

linuxcnc.org/docs/devel/html/config/ini-homing.html

cmorley wrote:

linuxcnc.org/docs/devel/html/config/ini-homing.html

Can you check: This example shows minimum and maximum hard limit switches with a separate home switch.
As you have :::: This example shows minimum and maximum hard limit switches with a separate home switch.

For both examples

Thanks for the work you have put in.

ahh yes! Thanks for proof reading.

Chris

cmorley wrote:

linuxcnc.org/docs/devel/html/config/ini-homing.html

Chris
re
The two H are the hard limit switches trip points

A<->B is the positive soft limits (MAX_LIMITS) = 10 units

B<->C is the home_offset (HOME_OFFSET) = -0.7 units Should this be a +ve value as used for the gantry square as I feel using -ve would drive back onto the switch. Just a thought!!

B<->D is the negative soft limits (MIN_LIMITS) 0 units

A<->D is the total travel = 10 units