This problem, would it be hardware, software or firmware???

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regpye
Posts: 16
Joined: Sun Nov 26, 2017 2:30 am
Location: South Australia

This problem, would it be hardware, software or firmware???

Post by regpye » Fri Mar 19, 2021 9:32 am

I have a puzzling problem that I have not been able to work out, maybe someone here can advise me on what is going on and how to fix it?
I have built another laser engraver/cutter, it is my fifth one, so I am not a noobie and have some experience.
The machine uses Arduino UNO (genuine) and a Chinese clone CNC Shield v3. The firmware is the latest GRBL 1.1h. The shield has been setup with two Y drivers, cloning the A drive to be the other Y. The Z axis is also used
The software used is the latest LaserGRBL and I am using that on several other machines without any issues.
The machine has been tested and can move in all directions and the intended homing position is the front left hand corner and Z at max positive position.
I am able to travel positive and negative until I do a homing. The homing is travelling in the negative direction. After homing I can travel only in positive directions, regardless of which direction I choose.
I checked the wiring and was able to home successfully, but the X and Y will only travel in the positive direction, even if I select negative travel.
I disabled homing and soft limits, and tried again after resetting the computer and the machine.
After manually positioning the tool in the home position by hand and setting zero X and Y, I am able to move in both directions no problem. By setting the travel lengths to the numbers shown on the screen, I am able to travel and stop in the correct positions and using the home button, return to the zero X Y that I set.
Once I turn on homing the problem starts again, so it must be something to do with the homing setup I think. I checked the limit switches and they are all OK .
The homing direction is correct for my machine, but maybe it isn't?? I am homing to the front left hand corner. Very thing appears to be as it should, until homing has completed and then I can no longer move in any negative direction, except for the Z axis.

My GRBL config file:

$0=10 (Step pulse time)
$1=25 (Step idle delay)
$2=0 (Step pulse invert)
$3=5 (Step direction invert)
$4=0 (Invert step enable pin)
$5=0 (Invert limit pins)
$6=0 (Invert probe pin)
$10=19 (Status report options)
$11=60.000 (Junction deviation)
$12=0.002 (Arc tolerance)
$13=0 (Report in inches)
$20=0 (Soft limits enable)
$21=0 (Hard limits enable)
$22=0 (Homing cycle enable) I turned this off to do further tests.
$23=3 (Homing direction invert)
$24=1200.000 (Homing locate feed rate)
$25=1000.000 (Homing search seek rate)
$26=144 (Homing switch debounce delay)
$27=3.000 (Homing switch pull-off distance)
$30=1000 (Maximum spindle speed)
$31=0 (Minimum spindle speed)
$32=0 (Laser-mode enable) I turned this off so I could test the laser without motion
$100=40.000 (X-axis travel resolution)
$101=40.000 (Y-axis travel resolution)
$102=80.000 (Z-axis travel resolution)
$110=10000.000 (X-axis maximum rate)
$111=10000.000 (Y-axis maximum rate)
$112=1000.000 (Z-axis maximum rate)
$120=1000.000 (X-axis acceleration)
$121=1000.000 (Y-axis acceleration)
$122=100.000 (Z-axis acceleration)
$130=840.000 (X-axis maximum travel)
$131=420.000 (Y-axis maximum travel)
$132=75.000 (Z-axis maximum travel)

regpye
Posts: 16
Joined: Sun Nov 26, 2017 2:30 am
Location: South Australia

Re: This problem, would it be hardware, software or firmware???

Post by regpye » Sun Mar 21, 2021 2:26 am

I am not getting any replies, so I stripped down all the wiring and started again. :(
This time I only wired the stepper motors and the limit switches.
I turned off homing in the configuration to do the first test. The X and Y motors needed reversing, so instead of changing the configuration file, I physically changed the wiring so that the motors moved in the right directions. I made sure that $3=0
The test showed that the machine can move in all correct directions if I move the laser head to the "wanted" home position first by hand.
All working well so far. :D
Next I turned on the homing and set it as default of $23=0. The test showed that the machine was trying to home in the top right-hand corner, which is not where the limit switches are, so I stopped everything and changed $23=3 which should be the bottom left-hand corner.
I rebooted everything and did another test. The homing went correctly, Z lifted up, double bounced and then the X an Y proceeded to the lower left-hand corner, The Y stopped first and waited until the X reached the limit, stopped and both did a double bounce. All seems normal, no warnings from LaserGRBL. :D
I then tried making a movement, and I could move both X and Y in the positive directions, but when I tried to go negative again, that is returning to home, the movements were both in the positive directions again. :(
This has got me really beat, I feel I have checked everything and just can't work out what is going on. :?

Bertus Kruger
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Location: Wellington , New Zealand
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Re: This problem, would it be hardware, software or firmware???

Post by Bertus Kruger » Sun Mar 21, 2021 6:18 pm

Have you tried another G-Code sender? UGS....

I think I have seen someone mention this issue on another site related to lasers.

regpye
Posts: 16
Joined: Sun Nov 26, 2017 2:30 am
Location: South Australia

Re: This problem, would it be hardware, software or firmware???

Post by regpye » Sun Mar 21, 2021 9:23 pm

Thanks Bertus, I already did that yesterday.

I decided to test with Universal Gcode Sender and without any other changes the laser worked perfectly. That showed me that the machine was set up correctly.
I then found in my old download folder an old copy of LaserGRBL from a few years ago, and installed that on the same computer.
I used the same configuration file from the new version so that all the settings were the same and tested again, and low and behold it worked fine.
So it seems that the problem all this time has to do with the latest version of LaserGRBL.
I went back to using the new version and tried again to make sure, and still the problem persisted. I also went a bit further and located the problem to being in the jogging movements only. I loaded a file and proceeded to do an engraving, and all went well. (As long as I didn't use homing)
Once I turned on the homing feature, only movements in positive directions were available using the jogging arrows. I tested again using a file and all still worked OK. Also with homing on I can move in the negative direction when homing, but not if I use the jogging arrows.

animal
Posts: 29
Joined: Sat May 06, 2017 11:03 pm

Re: This problem, would it be hardware, software or firmware???

Post by animal » Tue Apr 06, 2021 2:50 am

I may be wrong but I tought that with the Chineese clones you couldnt run anything newer that ver .9 ?
animal

regpye
Posts: 16
Joined: Sun Nov 26, 2017 2:30 am
Location: South Australia

Re: This problem, would it be hardware, software or firmware???

Post by regpye » Tue Apr 06, 2021 4:04 am

I have had no problems whatever running GRBL 1.1h and all others before that version.
Solved the problem as well, I reprogrammed GRBL to only use positive space.

I have changed the config.h file and removed the comments marks //
and now have #define HOMING_FORCE_SET_ORIGIN

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