NI 73xx motion control, maximum velocity

[genomar]

Hello!

Last time I was testing a new step motor controller. I discovered, that when I set the velocity higher than 2000steps/s, the speed doesn't increase more than 1968steps/s. I tried to set many configurations but they didn't work properly. I must do some tests with velocity much higher than 2000steps/s... Could you tell me what do I wrong?

Simple program was created in Labview 2011

Vision and Motion drivers -> NIMotion830

NI card -> NI-7334

Universal Motion Interface - UMI-7764

Windows XP

I tried only to set velocity of stepper motor in open loop.

Thank you in advance

Regards,

Mariusz

[AnalogKid2DigitalMan]

What is the make/model or specs of your motor?

How many degrees/step, what is the maximum rpm of it also?

Are the DIP switches in the UMI-7764 set up properly for your application?

-AK2DM

[genomar]

Thank you for your efforts you want to understand that issue.

But I don't understand why do you need the specification of the motor.

Anyway, in full step mode 200 steps/turn, ... ,  1/8 mode 1600 steps/turn...

I can easily reach higher velocity if I send the steps to the motor controller from external signal generator.

The problem is, UMI-7764 doesn't give properly frequency on Step(CW) pin. Even if the UMI is unconnected with motor controller, Step(CW) output doesn't reach frequency greater than 2kHz.

I carried out many tests. I set velocity to 5000 steps/s, ran program, checked frequency.

I attached print screen from osciloscope. It's below 2kHz. It should be 5kHz in that case.

I checked also if pins INHIN and INHOUT are set corretly. I don't use in that case INHIN so regarding to the specifications of UMI-7764, I left switch S2 to the bottom (active low).

[genomar · Accepted solution]

I found solution.

The problem was too small value of acceleration/decelaration. If program realises, that the rise time of velocity will be longer than 8,196ms, it stops increasing velocity below demanded value. I have no idea why, but maybe it is caused by internal counter that handles velocity method.

After I increased value of accel/decel block, Step output easily reaches a desired frequency.

I close the topic.