Software limit on Z axis travel in Easel?

I goofed and jogged 10 inches on Z axis in Eeasel driving the bit into my wasteboard.

Wish there were thresholds on Z axis downward travel…


Is there a way to get Easel to only work i millimeters?
My materials view is metric but bits size and jog controls always show up inches - every time I want to start a job.
That is where I goofed up.

Having to switch to metric all the time is both annoying and error prone

If you have homing switches installed you can have limits on X, Y, and Z. It is handled by grbl on the Arduino.

I have limit switches and the one on the Z axis do keep the machine from going too far upwards.
There is nothing too keep the machine from travelling too far down - or have I missed something?

You have add on limit switch on you Z axis or you’re talking about switch came with your kit. Because the Z switch is for Homing purpose, it doesn’t stop stepper when you’re jogging. Gives you nice broken smashed switch.

The switch kit that Inventables sells is really just homing switches. There’s one at the top of the Z axis and one at left for the X axis and one in the front for the Y axis.

When you home the machine first the Z axis moves up to trip the switch at the top, then X and Y move left/front to trip their respective switches. At this point the machine is homed and the software (grbl) knows where machine 0,0,0 is.

If you set the soft limits parameter in grbl ($20) then set the size of each axis in grbl ($130,$131,$132) then the software (grbl) will check for an out of bounds condition and if it is detected, the software (grbl) will alarm and stop the machine.

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Doh! I forgot about the fact that the included swithces are for homing only. Sorry, my bad.

Thank you for all input guys, much appreciated!

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Even though the switches are homing switches you can still use soft limits. Once the homing sequence is complete, soft limits do not use the switches.

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I second what @LarryM said… with soft limits in place and a homed machine the Arduino/gShield will not let a command go through that tells the machine to travel out of bounds. Hence not needing a switch at the lower travel of the Z- axis.

Do you have a tutorial or a link to set that up? I don’t really understand the $ commands, or where to put them. I crashed already a Z Switch limit, and I am scared it will happen again.


Thanks Phil.

So if I just do $20=1, does that mean that the machine will not travel further than the max already?

And, it is valid also for when you are joggling with your machine (when setting the bit to the zero point of your material, for instance).

[Edit] I shouldn’t do things from memory. Neither $X or $H will clear an alarm. You have to do a soft reset, or open and close the COM port to get grbl to reset after a soft limit is triggered.

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Understood. Very useful info Phil :).

When you say:

Correct but you probably want to measure what your real max is and use those numbers

Just to be sure, how do I measure, and what do I measure (and in what units mm vs inches ). You are talking about measuring with a measuring tape?

The limits for the axes (using soft limits) are set in grbl through the parameter set.

These are the defaults for the 500mm. For the 1000mm change 290 to 790.

$130=290.000 (x max travel, mm)
$131=290.000 (y max travel, mm)
$132=100.000 (z max travel, mm)

You may have to jog your machine to the limits of the axes to determine if you need to lower the number or raise the number. It depends on the way your machine is put together as to how far it can go without hitting an obstruction.

I have the 1000mm indeed.

And where can I see the exact position of each axis when jogging it? Do i have to re-do the homming first, I suppose?

Yes, home the machine and then do the jogging. If you are using UGCS you should see the Machine Co-ordinates. If you are using a different software program you’ll have to determine if it reports the Machine co-ordinates as you move.

I am just using easel for the moment, but i will download ugcs and test, thanks!

And, another question that I just thought about:
When jogging, do I go till the point of touching (activating) the home switches?
Or I have to go to the oppossite of each homing switch?

When you home the machine you will establish Machine Zero at the homing switches. At that point 0,0,0 is set. You want to move away from that point to see how far you can go without hitting an obstruction. Then you should be able to see in UGCS how far you have gone along an axis and where you need to set the soft limit.

Two things to be careful of with UCGS, you need to set the baud rate at 115200 and for this purpose you would want to set the jog distance to be in mm.

You need to have Java installed on your machine to run UGCS.

I think most people just use the defaults, which are fairly conservative.

hummm, ok. So maybe I just stick to the defaults. Nevertheless your info is great for later. I guess if it is 790mm, yes, that is fairly conservative, because you have still a long way to go to 980mm or the real height.
And I use mm whenever I can instead of inches.

Oh boy, here we go again…