controlling bipolar stepper motors with USB NI-6008 DAC

[Matt.M]

svijay,

You could use the 6008 to send pulses to a stepper motor.  The 6008 cannot source enough current to drive the motor, so you would need a different power power source for that, but it could output the digital signals needed to tell the motor to move.

There are two options for outputting digital waveforms.  Either you can use a digital output task, and control when the output goes high or low.  You would need to use software timing, which means this would be non-deterministic, but since you are only looking to run at 5 RPM software timing should be precise enough.

If you want to send a constant waveform you could use a counter output task to output a 5hz pulse, and the motor would constantly move at 5RPM, this method is deterministic since the timing is done on the 6008 instead of in software.

Regards,

Matt

[PaulRB]

Hi svijay, 

The USB 6008 will not be able to drive either of those motors (the motors need ~1A of current for full torque and the USB 6008 can only source 8.5mA per digital line). It can, however, send the step and direction pulses necessary for most stepper drives. To make the motor move at 5RPM, you would need to generate step pulses at 4Hz (48 steps/rev * 5 rev/min * 1min/60sec). This is certainly within the capabilities of the 6008, but all of the digital outputs are software timed. This could make the stepper motor movement seem jerky. Also, you cannot do a counter output task with the USB 6008, so you cannot get a hardware timed pulse train. Your only option is software timing and this may or may not offer the performance you need.

However, if you don't have a stepper drive, then that is the first thing you will need before trying to make this stepper motor move.

Thanks, 

[svijay]

Hello paul

I am having stepper motor driver which can able to drive motor of 2A rated current.  So my problem is only getting pulses from USB 6008.

And i dont want to count the pulses instead i am using position sensor for the feedback.

[PaulRB]

Hi svijay,

I'm glad you already have a motor driver. The next thing you will want to determine is the driver control signals. A lot of stepper drives take either a step/direction signal or a CW/CCW signal. The type of pulses you must generate with the 6008 will depend on the driver control signals. You will also need to find what kind of voltage levels, current levels, and signal types (sinking/sourcing) that the drive needs to see if the 6008 is even compatible.

Is there a reason you want to use the stepper in closed loop mode? It will make development easier if you just use open loop control. You can still monitor your feedback sensor, you just wouldn't use it to control the motor. 

Thanks,

[DaveOC]

Hi All,

I am new to labview and have a similar problem as Zenitac. I want to control a 2 phase Bi-polar stepper motor (see datasheet attached) via a L298N driver (see attached) and a USB-6008. I am unsure wether the previously posted VI's would be suitable for this driver (It doesn't seem to have a pulse port). 2 RPM would be fine for my application, all I want to do is rotate the stepper in 90deg. intervals nice and slowly, so I'm thinking 6.66Hz would be fine (200 steps/rev * 2 rev/min * 1min/60sec). I have NI Motion downloaded. An example VI would be great as I am completely confused at this stage!.. Also attached is a .jpeg of the L298n driver.

Best Regards,

Dave

[vijaysekar]

HELLO DEVDC

FINALLY I FIND A WAY TO CONTROL STEPPER MOTOR WIA PARALLEL PORT.  IT IS WORKING FINE WITH SLOW SPEED WITH GOOD ACCURACY.  iF U  WANT I CAN HELP U..  

[DaveOC]

Hi vijaysekar,

Thanks for your reply. I don't have a connector for my parallel port and I have not looked into controlling the stepper with it because I have a USB 6008 already.

I was hoping somebody could give me some advice in relation to using the USB 6008 to control it. 

I might send you a messgae if i cannot find any help using the USB 6008.

Thanks,

Dave

[matomato]

Hi vijaysekar

I will be interested to know how to drive a stepper motor with a parallel port.

Can you give me some info about it?

Regards

matomato

[vijaysekar]

hi matomato

I have attached the vi what i used to run stepper motor.

Connect first four datalines to your stepper motor driver and give values to the arry as 1,2,4,8.  if it is  not working try diffrent possible sequences

[robotek73]

Hello, I am trying to use your program since I am trying to accomplish something very similar. Is the wiring the same for the motor I have linked below? The motor only has 4 wires which I have attached to the appropriate A+, A-, B+, and B- ports on the driver. It doesn't seem to work so I am trying to troubleshoot any possible problems. If anyone has any ideas on this I would really appreciate it as I am new to LabView and looking for help. I have linked the motor datasheet below. Thanks.