ramping stepper motor

[killabyte]

hi, im driving some stepper motors using the l297 and l298. and i want to know if allowable to accelerate the motor using a ramp dc increase in the v ref pin in the l297.

this pin regulates the current delivered to motor windings through internal chopper circuit.

instead acelerating the motor using the clock may i control it through the current control?

should i use both?

regards

killabyte

 

[Skogsgurra]

I think that you should review the principles behind a stepper motor. That will make you avoid mistakes like the one you are about to make. Hint: A stepper motor "steps". The more steps it makes in a second, the faster it moves. The current does not influence the speed - only available holding torque at each step.

Gunnar Englund

http://www.gke.org

 

[killabyte]

youre right i was confused cause ive seen in a paper that i should control torque to make a better use of energy. somewhere i got blamed

thanks

killa

 

[killabyte]

im ramping linearly time (in seconds vs delay) i mean delay in each step.

im ramping from 0 to 1000 pulses per second, no load applied.

when near to 300 pps the motor got stalled, i guess the ramp is not so linear

i started using an initial delay of 200ms and after that the counter is increased in 500 us each time.

regards

killa

 

[nbucska]

you have tried to ramp it up too fast. The current determines the max. acceleration -- if the rotor can't
keep up with the pulses, it stalls.

 

[killabyte]

ok i´ll make a lower delay increase if anyone have tips...

regards

killa

 

[MikeHalloran]

Most steppers will follow a ramp that changes step time by no more than ~3 percent per step.






Mike Halloran
Pembroke Pines, FL, USA