Maxvel is too big error and stepper settings ques.

Hi everbody,

I builded a hexapod machine. Nowadays it try to control only one stepper motor. I performed the Stepper driver and Mesa 7i76 card connection. But i could not move the stepper motor. I take an error like this;

photo

My stepper driver is : Nanotec SMCI35

I suspect that stepper setting(Step Time, Step Space, Direction Hold, Direction Setup) on Pncconfig. What must be this settings ? My driver does not exist in the driver list. And the other question is : What mus be max speed and acceleration values ?

Thanks a lot.

It is obvious that English isn't your first language, so muddling through the documentation is going to be difficult for you. Ask lots of questions when you need help understanding anything.

It appears you have set your max velocity level higher than your chosen step timings can allow. First you need to calculate the step rates you need to achieve the velocities you want (or you hardware can do). The manual you linked to doesn't seem to mention any step timing limitations, other than maximum step rates (16KHz @ full steps or about 4800RPM for a 200 step motor). (Most step motors are never going to be able to turn that fast, I'd probably set my max velocity so the motor RPM stays under 2000rpm.)
There is some useful information here.
linuxcnc.org/docs/2.7/html/config/stepper-quickstart.html
and
linuxcnc.org/docs/2.7/html/config/stepper-diagnostics.html
and
linuxcnc.org/docs/2.7/html/motion/tweaking-steppers.html
Most of that info is geared towards software stepping, you are using hardware stepping, the main difference is you can ignore most every thing pertaining to base threads, but the basic concepts still apply.

As to what max speed and acceleration values should be, that should be calculated from the maximum capabilities of your hardware. (motor torque, max rpm, weight of parts moved by the motor, structure of the machine...) Only you, the machine designer can answer these questions.

As Andy Pugh stated in your 6x6 Stewart thread, your step scale value is very likely wrong

from your ini file:
# these are in nanoseconds
DIRSETUP = 10000
DIRHOLD = 10000
STEPLEN = 10000
STEPSPACE = 10000
STEP_SCALE = 400000.0

Since you are using mm scaling, this is 400,000 steps per mm, so these would be steps of 2.5 nM

Your step timings at this scale would make the maximum velocity be 0.125 mm/s