Increasing stepper motor torque/speed with MyRio FPGA

[Jenda02]

Hello, 

Quick question I have Microcon SX-16 2 phase stepper motor connected directly to MyRio FPGA  trough connector MSPC, DIO lines 0-3 where should be 5V. Program that runs this motor has one case that decides if it runs or not. Second one for clockwise or counter clockwise.   For loop includes another case with steps for full step control.   

Is there any way to increase torque, speed or a better way? Motor rotates piece  of fabric around two cillinders and motor is connected to one of them so it can transport small object on it. But when the object is too heavy so  the tension between cillinders is too much it stops rotating. 

Thanks for any reply.

J. 

[RIObotics]

Hi Jenda,

If you want to increase the "torque" or "force" for your stepper motor, you should be looking at your stepper motor driver to see if you can increase the current or torque from there.  Usually if your driver has enough power rating, you can increase your torque from there.  Changing your frequency of your pulses from myRIO will have no effect on torque.  However, increasing the frequency of your pulses will indeed increase the speed though. 

Oh and by the way, did you know there is a myRIO PWM Express VI that can do exactly what you are doing in FPGA?  Check it out here.

https://www.youtube.com/watch?v=mVN9jfwXleI

I made a myRIO tank a long time ago, just for fun.  I used the PWM Express VI, except I was not changing duty cycle, but I was changing frequency.  Therefore I can make my motors run at any speed I wish.  Check it out:

https://www.youtube.com/watch?v=pdbDDZlHsr0

If you want really nice acceleration and deceleration control, myRIO doesn't have this function, you'll need a motion controller to do this.  But it may be overkill for what you need right now.  See my other post here for an explanation for why you might need a motion controller.

Hope this helps

-John

[Jenda02]

Hi, 

I was afraid of this. Im trying to control it only by using fpga. I don´t have a driver and fpga lines do only 5V instead of 6-16V with driver. I have myrio toolkit 2020 may so it doesnt have Myrio express vi. Thank you for replying. 

J.