Inventables Community Forum

Another homing fail thread

Yes.

Any thoughts on where to go from here?

What happens when you home the machine?

Z should move up to contact the switch, then back off and contact again, slower.

Then both X and Y should start moving toward their respective switches and do the same pull off and contact again.

Yes, Z moves up, hits the switch, backs off and then moves up again slower. That’s where it bails on me. I get the alert at that point and it returns to a locked state. X and Y never attempt to move.

Post your $$ output from grbl here.

Grbl 1.0c [’$’ for help]
$$
$0=10 (step pulse, usec)
$1=255 (step idle delay, msec)
$2=0 (step port invert mask:00000000)
$3=3 (dir port invert mask:00000011)
$4=0 (step enable invert, bool)
$5=0 (limit pins invert, bool)
$6=0 (probe pin invert, bool)
$10=115 (status report mask:01110011)
$11=0.020 (junction deviation, mm)
$12=0.002 (arc tolerance, mm)
$13=0 (report inches, bool)
$20=0 (soft limits, bool)
$21=0 (hard limits, bool)
$22=1 (homing cycle, bool)
$23=3 (homing dir invert mask:00000011)
$24=25.000 (homing feed, mm/min)
$25=750.000 (homing seek, mm/min)
$26=250 (homing debounce, msec)
$27=1.000 (homing pull-off, mm)
$30=1. (rpm max)
$31=0. (rpm min)
$100=40.000 (x, step/mm)
$101=40.000 (y, step/mm)
$102=188.976 (z, step/mm)
$110=8000.000 (x max rate, mm/min)
$111=8000.000 (y max rate, mm/min)
$112=500.000 (z max rate, mm/min)
$120=500.000 (x accel, mm/sec^2)
$121=500.000 (y accel, mm/sec^2)
$122=50.000 (z accel, mm/sec^2)
$130=790.000 (x max travel, mm)
$131=790.000 (y max travel, mm)
$132=100.000 (z max travel, mm)

The following link has a .zip file with a version of grbl that is stable.

Load this version of the firmware into the X-controller.

You can use Xloader to load it in.

After you load it in we need to check the grbl parameters to see if you need to make any changes.

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Ok…loaded that hex file. Here’s the $$ output…

Grbl 1.0c [’$’ for help]
modified by Larry Mayberry
$$
$0=10 (step pulse, usec)
$1=255 (step idle delay, msec)
$2=0 (step port invert mask:00000000)
$3=3 (dir port invert mask:00000011)
$4=0 (step enable invert, bool)
$5=0 (limit pins invert, bool)
$6=0 (probe pin invert, bool)
$10=3 (status report mask:00000011)
$11=0.020 (junction deviation, mm)
$12=0.002 (arc tolerance, mm)
$13=0 (report inches, bool)
$20=0 (soft limits, bool)
$21=0 (hard limits, bool)
$22=0 (homing cycle, bool)
$23=3 (homing dir invert mask:00000011)
$24=25.000 (homing feed, mm/min)
$25=750.000 (homing seek, mm/min)
$26=250 (homing debounce, msec)
$27=1.000 (homing pull-off, mm)
$30=12000. (rpm max)
$31=0. (rpm min)
$32=0 (laser mode, bool)
$100=40.000 (x, step/mm)
$101=40.000 (y, step/mm)
$102=188.947 (z, step/mm)
$110=8000.000 (x max rate, mm/min)
$111=8000.000 (y max rate, mm/min)
$112=500.000 (z max rate, mm/min)
$120=500.000 (x accel, mm/sec^2)
$121=500.000 (y accel, mm/sec^2)
$122=50.000 (z accel, mm/sec^2)
$130=740.000 (x max travel, mm)
$131=790.000 (y max travel, mm)
$132=100.000 (z max travel, mm)

Change the following:
$10=115
$22=1
$30=1.
$102=188.976
$130=790

Try homing again.

Unfortunately, nothing changed. The behavior is exactly as it was before.

Maybe it’s Chillipepper, do you know how to use the Arduino IDE serial monitor?

I’ve only ever been able to get it to return the result of ? It doesnt seem to respond to anything else. So, that being said…I may not know what I’m doing with it! :slight_smile:

Let’s try something else first. Start the homing cycle and wait for the Z axis to finish.

Then manually (keep your fingers out of the machine) press the X homing switch, wait about 1/2 second manually press the X homing switch again.

Then do the same for Y.

As I attempted to do this, I paid closer attention. It’s not actually backing off Z all the way. It starts to, but not enough for it to release the trigger on the z-switch before it fails. That being said, I can’t manually press the X because it trips out too quick.

Just as a test change $27=5

Try homing.

Larry, that’s brilliant. That was the solution. Thanks so much for all your time! I really appreciate it!

Ok. Play with the pull-off to get one that works reliably for you. The only penalty for a long pull-off is time to complete homing.

Right on. It definitely is time consuming on that slow second move to the trigger. I’ll adjust it down a bit.

If it gets to be too much of an issue you might get better results by replacing the switches. Seems like the ones you have are a bit loose in their action.

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@LarryM In the light of morning with a fresh mind, I think I figured out where this problem came from. Just before I stopped using the machine months ago, I smashed the Z switch. As part of getting it back up and running, I replaced the Z switch with a new one. I ordered a handful from Amazon, so they aren’t entirely identical to the ones that came with the machine. The Z switch obviously has a different trigger point. I may replace the X and Y over time, but for now I’ll compensate with the $27 setting.

@PhilJohnson, I imagine I can probably get away with a setting of 2 or 3. I’ll play with it tonight. I figure that will be tolerable for now.

On a side note, just as a curiosity, I was thinking back and at one point yesterday, it DID retract far enough and made the slow second pass when homing Z. What I remember now is that apparently only happened when I used Easel to attempt homing. Not sure if Easel imparted slightly more liberal variables or not, but after the second slow pass, it still wasn’t fully releasing the switch so it wouldn’t move forward with X or Y still. shrug

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