stepper motor vi

[SAL2005]

Hi,

I am relatively new to the labview codes for stepper motor control.

Let me start by writing what I am trying to achieve. I am trying to control a valve with a stepper motor. I have a bipolar stepper motor from Oriental motor co. mounted on the valve. I dont have the driver/ controller for the motor. I am thinking of buying a third party low cost controller that will drive the motor and use the labview to talk to the controller.

I am using labview 6.0 and I guess but I am not sure if one can write a simple stepper vi. that will allow one to get around. I already have 6024E data aquisition card running on the computer.

Can anyone suggest how should I go with in achieving this?

Thanks

SAL  

[David S.]

Hi Sal -

Most motion applications involve a controller, a drive, and a motor.  The controller runs a deterministic feedback-control loop and sends updated commands to the drive.  A separate drive unit is necessary because the PCI/PXI bus is incapable of sourcing the current required by the motor.  The drive also takes commands from the controller to handle error situations and shut down the motor appropriately.

NI offers a line of motion controllers (PCI/PXI-733x, 734x. 7350) and motor drives (MID-760x, 765x) that fit most stepper and servo systems.  The controllers have a driver call NI-Motion and an associated API.  This API lets you program your controller in LabVIEW, LabWindows/CVI, MSVB, etc.  If you choose to use a third-party controller, it will have its own API (VIs and function calls) provided by the vendor.

If you would like to program your own control loop to handle custom inputs and algorithms, you can use the NI SoftMotion module.  This module allows you to create a custom controller from your LabVIEW Real-Time system.

[Brian_Beal]

Could you provide some more details of your application?  Are you trying to position the valve, or just control pressure, flow, etc.?  Are there stop positions on the valve, or can it continue to turn?  There are many hardware options available, depending on your requirements.

[SAL2005]

Hi,

thanks again...

I am just trying to set the position...

[Brian_Beal]

There are a couple of options.  You could have a stand-alone controller/drive unit that you use Labview to communicate with.  You would send it commands to go to a certain position.  You could also use the analog output of the DAQ card to set a position using an analog input on your controller.  You would have to have a resident program in the controller that sets position based on the analog input.  You could also use the DAQ card to control a step and direction drive, but this is more difficult.  You could also buy an NI motion controller.  There are many options, but it depends on how much you want to spend and how comfortable you are with motion controllers.

[SAL2005]

Hi,

Thanks for giving me different options. I do not want to spend too much money and still be able to get it out. I bought a cheap bipolar stepper controller. Now it came with the software with various parameters changing options which I can use. I tried with the software and am able to control the motor. But I dont see how I can run with labview? What do I need ? I have the dll files on the programs?

Regards,

Sal

[David S.]

Hi again Sal -

If the API for your controller is offered as a set of DLL functions instead of one or more VIs, you can use the Call Library Function node in LabVIEW to access the methods inside those DLLs.  For more information about using this node to call C-based functions from a DLL, please see this tutorial: Can LabVIEW C? - Example 3: Using the Right Tools with LabVIEW

[SAL2005]

Thanks,

I will check on that and see if I can work it out.

SAL

[Electr]

Hi,

We have to control a stepper motor valve as attached. The link given is no long existed. Please help the follows.

- What DAQx module can we use for communication to control the on/off valve from LapView? I have Ni9472 8-channel Digital Output modules, can I use it?

- What else components do we need?

- Appreciate if you can help with a specific Vi.

Thanks,

Best regards,