Ask Grbl CNC questions here.

Hi everyone, I try to get an eggbot running on a arduino mega and ramps 1.4. There is a grbl hack "spindle_control.c" for the normal "grbl" arduino Uno that can be used for pen plotter and eggbots. Is there a way to use this code in the current "grbl-mega".

By the way: I already tried to compile the standard grbl for the mega board and figured out that the pin mapping should be compatible (same pins numbers are defined in the CPU map) but it doesn't work. Also my favorite idea to inserting the "spindle_control.c" code in the "grbl-mega" leads to compiling errors.

Is there a easy way to control a z-axis servo with grbl-mega?

 

Thank you for your response. I was already thinking about buying a arduino uno to overcome this problem.

Nevertheless, if I understand the challenge correctly. The main problem to use a servo on the spindle pwm pin is, to find the configuration value in grbl where you can change the spindle pwm from kHz zu around 50Hz.
This should be independent of the used board and probably work also in the future with grblHAL.

 

That's it. Marlin works out of the box. I used the last release 1.1.9. with arduino IDE. Thank you.

I tried to change the prescaler in grbl but it doesn't work for me. In the end marlin was the easier solution.

 

I have suddenly developed a problem. When advancing the X axis the Z axis goes up by a the same amount. I checked wiring and everything is fine with no noticeable loose terminals. When moving the Z axis independently, everything works fine, so no crossed wires. I am using Arduino Mega and TB6600 drivers. Everything worked well for many months until now.

Any suggestion what might cause this?

 

Hi, would really appreciate any help on a homing issue. I have a flat bed cnc router running grbl 1.1h. I get the same result using Open Builds Control or UG Sender. When I Click <Home All> the Z axis homes, then the X axis motor just hums loudly with no movement. While the motor was humming I pressed the x axis limit switch and it is not functional. I get no error codes or windows, or any lines of code in the "serial console/console" window. X axis motor works flawlessly with every other process. Every other part of the machine works flawlessly. all limit switches work as intended at other times. Looking forward to any help on this issue. Thank you.

 

Hi Peter, thank you for responding. Yes it moves fine while jogging. I think we have $24 set at 25 and $25 set at 500. Would need to confirm that tomorrow. If the z axis feed rate is ok should not the X axis be ok as you cannot set different rates for xyz. Or is it the case, its a different unique stepper motor therefore may not work with the same settings. Also no matter what we have it set at, is it (as you suggested) worth trying a lower setting.

 

Thank you for the information. We will check on it tomorrow (11:30 at night here in Australia) and also try other feed rate settings as you suggest. Thanks once again.

 

Issue Solved. The homing was working fine, we just did not realize it. We thought the Z axis had completed its 2 steps ($25 and then $24) and then the humming was the start of the X axis homing. It sounded like a poling electric motor and we saw no movement, so we aborted. The Z axis had actually only completed its $25 (500) step. The loud humming was the Z axis $24 (25), so low we did not observe movement, just happens to be the noise a slow setting makes. We set $24 to (100) saw movement and realized the Z axis was still doing its $24 step. Probably would have eventually realized our mistake, but was solved a lot quicker and with a lot less headaches with direction from you as to where the issue may lie. Thank You. Great Forum.

 

mr. Jeon, ive chatted ith mr vanderbuilt, now he want me to buy a black box, but ive envested so much, time and money, i have an openbuilds table with sfu 16mm 5 pitch ball screws, arduino and tb6600 controlers my first table was 400mm by 400mm worked great, now ive evpanded to 1000 by 1500mm it used to work flawlssly till upgrade, tb6600 are set to 2.8 amps and 1/8 dtep seems to run good to a point, i can make it go 100cm in all axis when calibrating, but then comes problems, in jog mode if i go y pos it will somtimes go pos or somthimes go negitive , sometims in x axis too, below is my grbl settings, ive used t2 laser, laser grbl and openbuils cam and controls, if i design a box in any software when in fire ,up my cnc it doesa lid with an open box, if i do a circle it comes out nothing like a circle, i down loaded the butterfly in OB cam sent it to OB control, i started my cnc and it looks like a dragon with its wings, cut off, the only thing that works is the letter {L}if afaried if i buy a black box {witch i did last night} will not work either, most of open builds rods are 8mm mine is 16mm with, a 5 pitch, inspent $400 last night but i have a pile of arduino stuff still sitting around please im at an end thanks robert

 

Robert:

There are so many errors in your GRBL settings it's hard to know where to start. No wonder your machine is not working. Almost every setting is incorrect.

Buying a Black Box is not going to help if you mess with its settings like you have done here.

Go back to the GRBL WIKI on Github and carefully read the settings descriptions and follow the suggestions there. Read this also:
GRBL Settings and Calibration – 3D Tech Works
Note that the settings in this are examples only, and are for an older Ox style CNC. Don't use them for a Workbee.

There are only two major differences between your machine and a standard Workbee, A) the length of the Y axis, $131, it should be 1500mm. $132 should be about 90, and $130 should be 1000. B) the calibration constants in $100-$102: these will depend on your screw pitch and microstepping settings. For example, I find it hard to believe your Z axis is 2000 steps/mm. Also, your acceleration settings are out to lunch.

All the rest will work fine with the default settings. Use the settings for the Workbee 1510 for a starting point. DO NOT change a setting unless you understand exactly what it does. Sample 1510 GRBL settings file is attached.

MG

 

I've been using TB6560 drivers for 6 years, (over 600 of them) and I can count the number of failures on 1 hand. You are sort of correct, a lot of the TB6600 drivers are not TB6600's at all, but they are not TB6560's either. The 6560's have manual dipswitches for setting hold current, and decay mode, which 6600's do not. True TB6600 drivers are awesome, one of the best stepper driver designs for their time, regardless of price. The 6560 and 6600 are both a bit long in the tooth, but still work flawlessly.

Big difference between a few $10 TB6600 drivers and a $300 Gecko 540, but the former works just fine for a hobby class machine.

And if the user messes with the GRBL settings like this fellow has, a Black Box wouldn't work so well either. His problem has nothing to do with stepper drivers and everything to do with proper setup.

MG

 

Hoping to get some assistance. I would be very greatful.

Some backstory, I have an extruded aluminum cube, with an Arduino Uno, CNC shield, 4 stepper Drivers and Motors, 3 limit switches all set up correctly and working. I have the spindle on Z mounted horizontally with movement forward and rearward, I have the Y moving the spindle left and right. I have 2 steppers for X being the table (moving up and down) and they are cloned on X and A with the jumpers to clone X to A.

When I run GRBL, $X, $H I get a perfect Homing action for z moving rearward, clicking the limit switch and moving off it. Y moves right, clicks the limit switch and moves off it.

X is my problem.

X reacts different each time.

Some times it just moves up and down a small amount and stops. It never hits top (-) limit switch. Then as Y starts to travel to center, X starts to move down and bangs over an over at the bottom of the machine trying to keep going.

Other times after Z and Y home correctly, X starts to move up and bangs at the top trying to keep going and the limit switch does not stop it.

I think the GRBL code to move X upward a few MM is X-10 but sometimes that moves it up and sometimes that moves it down?!?! And if I enter X10 sometimes it goes down and sometimes it goes up?!?!

 

Bad wiring to the X motor is the "random direction" thing, one of your phases isn't fully connected. Homing... Does your sender respond to you manually pressing the home switch? CNC Shields, if they're not official ones, frequently don't work in some way.

Standard Cartesian CNC directions are the right hand rule- middle is Z+, index is Y+, thumb is X+. Same setup as Fleming's right hand rule. Personally I'd have Y+ going up and X+ going right, but Y+ going right and X+ going down is technically correct.

 

34356"]Robert:

There are so many errors in your GRBL settings it's hard to know where to start. No wonder your machine is not working. Almost every setting is incorrect.

Buying a Black Box is not going to help if you mess with its settings like you have done here.

Go back to the GRBL WIKI on Github and carefully read the settings descriptions and follow the suggestions there. Read this also:
GRBL Settings and Calibration – 3D Tech Works
Note that the settings in this are examples only, and are for an older Ox style CNC. Don't use them for a Workbee.

There are only two major differences between your machine and a standard Workbee, A) the length of the Y axis, $131, it should be 1500mm. $132 should be about 90, and $130 should be 1000. B) the calibration constants in $100-$102: these will depend on your screw pitch and microstepping settings. For example, I find it hard to believe your Z axis is 2000 steps/mm. Also, your acceleration settings are out to lunch.

All the rest will work fine with the default settings. Use the settings for the Workbee 1510 for a starting point. DO NOT change a setting unless you understand exactly what it does. Sample 1510 GRBL settings file is attached.

MG[/QUOTE]

 

I did as you said and ordered a black box and 3 nema 23 high tork motors,

How do you know if a tb6600 has failed? All 4 light up, if I hook up just 1 db6600 to arduino and a motor it looks fine plus I tried on pin 2 and 5. 3 and 6. And 4 and 7 for each axis,

Can they lihjt up and still be bad?

 

[QUOTE="Metalguru, post: 116404, member: 34356"The 6560's have manual dipswitches for setting hold current, and decay mode, which 6600's do not.
MG[/QUOTE]
If my 6600 has those switches it's not a 6600 then?

 

Z axis is not being used, dip switches are set to 1/8 ,amps 2.7. Fyi still looking for a easy way to fest the db6600,

 

If my 6600 has those switches it's not a 6600 then?[/QUOTE]

Correct. It's a TB6560. TB6600's have automatic decay mode and auto 50% hold current (there may be a switch to enable/disable this feature, but you can't set the hold current). Other than that, they are pretty much identical. The TB6600 is a slightly newer design, but they are pretty much interchangeable.

Unfortunately, a lot of Chinese suppliers call everything a TB6600, even when it's not.

MG

 

You test it by hooking it up to a motor. If the motor runs, it's good. I've never seen one partially fail, ie work but not work properly. Generally, it either works properly or it doesn't work at all (magic smoke has been released). I suppose it could have a blown optocoupler or something, but pretty unlikely.

MG

 

LOL, I feel a little better now. Just checked my drivers and they don't have the switches for the decay mode only for micro stepping and current settings (which my 540s have too).

 

Ok, black box and 3 new nema 23 hight torque due tomorrow,
1 turn off all power
2 add new motors and check wires
From here where should I go , I don't want to blow up anything,, connect to blac box??

Thanks robert