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Strange situation with stepper motor

Posted by Darksliver 
Strange situation with stepper motor
October 14, 2017 12:51PM
Hello to everybody,

I have a stepper driver shield (for Arduino UNO) and Arduino Mega2560 grinning smiley
(And use GRBL for mega2560)

I connected only one motor on z-axis for my tests and this is the result.

Connect pin for DIR and STEP, connect pins for clock and strobe, connect pin for enable.
Connect Vin and ground, 12V directly on the shield and USB to arduino for the logic.

All is ok and the stepper work great.

BUT

on arduino there is a 5V pin. I read many article on internet and this pins is needed to power the logic.
If I connect the stepper going into a freeze, if disconnect work fine.

How it's possible? I break my electronic if i leave it disconnected?

Link of schematics
[www.futurashop.it]

Thanks
Re: Strange situation with stepper motor
October 15, 2017 12:14AM
It seems, the shift registers need some initialization code to configure MS1-MS3 of the drivers? Or are they pulled to GND automatically?
Why not use a RAMPS shield with GRBL?
VDX
Re: Strange situation with stepper motor
October 15, 2017 07:21AM
... could be, your drivers draw more current from the +5V of the Arduino, than the voltage regulator can deliver -- so the +5V of the Arduino breaks down and the program stops.

If it's working fine without connecting, then the +5V for the drivers are sourced elsewere ... so better let it "open" ...


Viktor
Re: Strange situation with stepper motor
October 16, 2017 11:06AM
Quote
o_lampe
It seems, the shift registers need some initialization code to configure MS1-MS3 of the drivers? Or are they pulled to GND automatically?
Why not use a RAMPS shield with GRBL?

I thought about changing the shield but I've payed for it and honestly has become a matter of principle grinning smiley
That I know the pins MS1-MS3 on driver are as basic (full step). I have not touched them; the GND of the shield are all connected.
Forgive me if I say something stupid but it's my first electronic experiment.



Quote
VDX
... could be, your drivers draw more current from the +5V of the Arduino, than the voltage regulator can deliver -- so the +5V of the Arduino breaks down and the program stops.

If it's working fine without connecting, then the +5V for the drivers are sourced elsewere ... so better let it "open" ...

With multimeter on shield I've detected a voltage about 4V when test driver's pin 5V with 5V disconnected in fact grinning smiley
This thing becomes stranger to any test, but everything works great with the pin disconnected so I'll leave it and see what happens when mounts the engines and will be under stress

I pray do not cause a fire or my wife will not be so happy I think hot smiley
Re: Strange situation with stepper motor
October 25, 2017 12:21PM
Hello to everybody,

yesterday I try to change GRBL config because z-axis of my cnc must stay in tension to withstand weight of axis. I set $1=255 (Step idle delay, milliseconds). 255 = always on.

Stepper motor start clicking repetitively eye rolling smiley
Does anyone have any idea why? It's a problem?

For info I have a Nema17 1,5A stepper motor and setting VREF on shield drivers (pololu) to 0.42.

Thanks
Re: Strange situation with stepper motor
November 01, 2017 10:57AM
Ehm.... Anyone have an idea? I have block all the project because I do not want to break anything eye popping smiley
Re: Strange situation with stepper motor
November 01, 2017 05:05PM
Keeping the motor ON all the time
the motor will heat up and get very HOT.

Use a motor brake or mechanism to hold axis.
A worn drive or counter-balance could work

confused smiley
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