[Gilbert]

I am using 100 oz-in motor, 6 wire, unipolar, 200 steps/rev, 1.4A/phase, tied to SG 3524 PWM with 12 volt input, and a 5804 controller.

I am getting 400 steps/sec no load

Is that all I should get out of this setup or am I doing something wrong? What kind of affect can I expect if I introduce half step or increase the input voltage to 35 volts?

I am hoping to achieve 1600 – 6,000 steps/sec. Do I need a large motor?

Thanks for any help.

[pminmo]

Couple of questions. How have you implemented the PWM, on the high side or enable/disable the 5804?
To get your performance up you need to power your steppers at a higher value, closer the 35V max of the 5804.

[H500]

6000 steps/sec should be easy to achieve with a higher voltage. I can do about 5000 rpm with a similarly rated motor.

[Gilbert]

Phil, I am not sure what you mean by high side or enable/disable, but here is my circuit.

H500, what voltage are you using.

[pminmo]

where is the 3524?

[Gilbert]

The 3524 (PWM) is on page 1, and the 5804 (motor controler) is on page 2.

[pminmo]

Now I see,
If my tired brain is seeing this correct, I don't think you will benefit from a higher voltage. You pwm is creating an average voltage to maintain the correct current, truely a pwm. In the stepper world a chopper senses max current and interrupts current flow for a fixed time, so you get the benefit of the higher supply voltage. i.e. the term chopped vs pwm.

H500, your getting 5000rpm? Thats over 16000 full steps a second! What kind of setup are you getting that with?

[H500]

Gilbert:
I'm using 33 volts, with no load on the motor, and Mach1. To achieve that speed, the accelleration must be set appropriately.

If you're only using 12v, I don't think your pwm circuit will even switch off at the higher rpm's, since the current won't have time to build up to the threshold level due to the coil inductance. I'm also driving 2 coils simultaneously. I believe your circuit only drives 1, so you get about 30% less torque.

Phil:
It's the AVR chopper I played with last year. It was based on the 2313 @ 10Mhz. Keeping up with the stepping was no problem, but the chopping at 20khz taxed it to the limits with the unoptimized C code.