Gantry jogs off rails

[goodman100]

I Have a Star-Lab table and am trying to get it fine tuned. I got the gantry squared up and after I home the x axis and set the soft limits, when I jog the gantry too far, it goes off of the rails and I have to square it up. Is there a setting where I can keep it from jogging past the rail and homing switches.
Thanks

[djreiswig]

What year is your table? On mine I'm using an Xbox controller to jog and it will go wherever you make it go. You can crash it on either end of any axis is you jog too far. The limits don't do anything when jogging. I don't use limits. You don't really need them if you have steppers.
I suppose you could wire up some switches and estop it if you jog too far, but stopping too quickly can sometimes mess up your zeros.
I just jog slowly and watch what I'm doing and don't really have an issue running off the rails.

[djreiswig]

Do you have home switches on your x axis? If you adjust them correctly you can just rehome and it should square itself.

[tcaudle]

Limits, if setup correctly, will stop motion during a jog. You can also define Homes as dual purpose (home and limit) BUT if you are doing a Homing or touch off move it ignores limits.
You have several options for mechanical limits . Where you have limited inputs you can wire them in series using Normally Closed switches in a string and tie them all to one input so if ANY swithc is tripped it OPENS the string and causes the limit to trigger/

You did not state the age or model and if its the newer CommandCNC version. If it is, you have even more options . You can set "soft Limits" on each axis that will stop motion if you try to job (or even load a file that would move beyond the limits). It's based on the fact in CommandCNC the Homes define the "absolute" zero positions (Table Zeros) and any move that would put you past the absolute limits will trip the soft lmit.

The software keeps your current positions as an offset from table zeros (no matter what the readouts say) so that no matter what happens you can get back to you work positions simply by re-homing the axis.

Having dual homes on the gantry axis helps a lot because it sell squares every time you move to home at zeros.

Finally, the other thong you can od is use "hard" limits * (Stops) if its a stepper system. Steppers "Stall" and it sounds bad and you lose position on the readouts BUT it doe snot harm anything. Clamp a piece of hard rubber on the rails.

[Fastyankee]

This will happen if you jog the machine to fast they made the linear gear rail to short on the x axis.

[BTA Plasma]

This is not true. You must home the machine before trying to jog the machine into a limit. Did you know the gantry axis is impossible to crash or damage the drive system? Also it is impossible to drive a gantry off the machine. There is a hard stop on either side, a limit switch on the front and home switches on the back.

[Fastyankee]

This is not true. You must home the machine before trying to jog the machine into a limit. Did you know the gantry axis is impossible to crash or damage the drive system? Also it is impossible to drive a gantry off the machine. There is a hard stop on either side, a limit switch on the front and home switches on the back.

Actually it is true . If you jog the machine at full speed it will run of the rack if your not aware of it.

[BTA Plasma]

Yes if you do not home it will run off the rack but not off the rail. That is why homing is very important. Running off the rack keeps the operator from damaging the machine. It will glide into a hard stop rather than the operator running it hard into a hard stop under power. Once homed the machine can never over run the rack unless the factory travel limits were changed. It is a safety feature having a software limit and a soft mechanical limit.

-Matt