issue with stepper motor using A4988,CNC sheild and grbl library

The stepper motor oscillates around the starting point and arround the stopping point when using the grbl library as you can see in this short clip


https://www.youtube.com/watch?v=JrjhW3ktgqU

If I do not use the liberary, the stepper motor behaves well.

Any help will be appreciated.

Philip

Reduce the acceleration and let us know if it helped

the motor is running perfect now
many thanks


the accelaration setting was
$120 = 10.000 (x accel, mm/sec^2)


I took it up to
>>> $120=200


It is working fine now


As I have no clue what I am doing as this is my first chance to play with the cnc sheild, I realy appreciate any input.


Many thanks hfjbuis

Great to hear it is working.
Enjoy learning to use steppers.
Huub

I could have stopped the reporting here, but I did not feel comfortable in case someone reading I might confuse him.

I find several issues

while it is true that pumping the acceleration up has helped(I guess overcoming the rotor inertia) the root cause of my issue was that one of the motor wires was bad quality and break. It was tricky because visual inspection shows ok.

Due to running the motor single phase, there was hesitation in the take-off and landing of the motor. The higher accelaration helped overcome this hesitation. But the root cause was a lose wire,

So now I brought the accelaration down to 50 and corrected the lose wire and things are more than perfect.

The reason I found the lose wire because the motor take off in a different direction every time I give a command to rotate possitive Y.

I searched the net and found quite few people have this issue and where able to nail it down to lose wire.

conclusion : if the motor decides to rotate in a different direction while given the same command (Say +y ) first suspicions should go to single phase operation due to lose wire or failed motor or something of that sort.


Thanks hfjbuis for taking the time to post in my thread.

Thanks for reporting the actual cause. Now we both have learned something new
Huub