Soft Limit Setup

I'm working with a sim at present prepping for the real machine.  If I jog into a limit the sim/machine faults and I cannot reverse direction to get out of the limit.

Is there a way to setup soft limits so the machine stops motion at the limit, doesn't fault, and can still reverse motion without needing to disable limits or re-home?

 

Limit switches should never be hit in normal function and will only occur because of a fault (in a properly configured setup).

I don't believe a function to not fault when limits triggered exists (nor should it)

There is the maximum physical travel of the machine (usually with limit switches close to either end of this).
Then there are the 'soft limits'/ axis travel defined in your ini file.

E.g. real max physicial travel 320mm.
Limit switches 5mm from either end = 310mm between limit switches
Axis travel 300mm
Then you need to tell LinuxCNC where the axis is (in relation to the actual allowable physical travel / limits)
Usually done with a home switch inside limits, or using on limit switch as home+limit

If axis not homed correctly, then you can end up hitting limits

Did you home the machine?
There is usually a button to 'override limits' to back away off the limit switches.

There are no limit switches, I'm in Sim mode presently.  So over travel should not be possible. 

So isn't the Min_Limit and Max_Limit the travel limits, and not fault limits?

Please answer the questions explicitly.
Did you home the machine?

You don't need home switches or limits switches or a real machine to home the machine.
Homing sets the reference for the machine origin which sets the soft limits.

If you didn't home - the machine doesn't know where it is.

If this for your robot and you are using custom kinematics/ switchable kinematics you will need to switch the axis limits from cartesian to joint when switching from 'World' to 'Joint' mode (and the other way around).
For an example have a look at the 'millturn' sim config.
M428/M429 will call 'M128/M129' respectively which is where the axis limits are switched between the two sets defined in the ini.

[edit]
Here is the melfa-sim config with axis limit switching added:
 

Note that when jogging in WORLD mode you will still be able to jog into the joint limits. That is a limitation of the current state of linuxcnc.

Aciera post=301669 userid=25994If this for your robot and you are using custom kinematics/ switchable kinematics you will need to switch the axis limits from cartesian to joint when switching from 'World' to 'Joint' mode (and the other way around).
 

Yes exactly, my 5-DOF robot.

I reset the robot, Home the robot, select World jog mode.  Then if I jog into a limit I can't back out without disabling the axis limits or re-homing the arm. 

All axis are rotary joints, so I thought when any individual joint approaches its limit it would soft stop.  I really only need axis limits not Cartesian for a maximum usable envelope.

 

Aciera wrote:

[edit]
Here is the melfa-sim config with axis limit switching added:
 

File Attachment:

File Name: melfa-sim.tar.gz
File Size:34 KB

 

Thanks for the example.  It will take me a while to grasp how this works.