Mesa 7i96 Stepper oscillating at idle

Hey guys,

I´m currently still on the "dry run" of my controller without the machine itself attached.
My stepper motor is oscillating at idle. But not always only sometimes when I jog the axis. The axis DRO shows that it hunts the position for about 0.005mm.

My the encoders on my steppers count 1000 pulses. So I set the Encoder Scale to 800 for a 5mm pitch ballscrew.
I confirmed this setting by turning the motor shaft for one turn and the DRO in Axis shows 5mm.

My stepper drivers have default 400 steps per revolution so I set the microstep_multiplicator to 2.

I tried with various  PID settings to get this right and read in the forums to delete the ferror line in the hal file and stuff
but nothing seems to work.

I´m currently only testing and trying and adjusting the x axis, so only one stepper is hooked up.

Can somebody take a look on my hal and ini files? Maybe I got something wrong or out of spec?

Thank you very much in advance.

Greetings, Mike
 

I just discovered something.

When I control the axis with MDI and say for example G0 X35.125
it works perfectly. No oscillation whatsoever.

I send the axis now for 50 60 times from X0 to X35.125 and back without oscillation.

As soon as I enter X35.123 or X35.127 it oscillates as soon as it stops.
It seems that every move where the third didgit behind the decimal point is not 0 or 5 it starts oscillating and hunting for 0.002 0.003mm.

I don´t have any idea how to fix this tough...

Take a look in deadband section.
linuxcnc.org/docs/2.8/html/config/ini-co...t__lt_num_gt_section

Oh I didn't know there was a setting for this.
I'll try that out tomorrow.

Thank you very much.

I'll report back.

That absolutely did the trick.
I set the Deadband value to 0.005 and now it works just as intended.

Sometimes when I jog the axis manually at a high speed it corrects the stopping position for a split second but it stopped with the hunting.

I can fine tune this on the machine later. As for the moment, everything works perfectly now.

Thank you again very much.