DAQ6251

[Duy]

Can I use Multifunction DAQ 6251 for controlling an induction motor drive system with vector control method ?  

[gt3000]

Hello Duy,

The M-Series 6251 has Analog Ouput channels, as well as Digitial Output channels.  Based on the motor type, one of these outputs can possibly be used, depending on the update rate required by the device. 

I have look up Induction Motor Drives the employ a Vector Control Method.  What type of input does your drive require?  At which rate would you like to update?  Do you already have the USB/PCI 6251?

It seems to me that an Vector Control motor may not differ too much from a standard servo on the side of the input requirement.  The main different could be in the internal working of the drive, which tries vector mathematics to compensate for the load on the end. Please let me know if that is how you understand the working as well.

Regards,

[Duy]

Dear George,

Thank you very much for your reply.

Actually, I already have the PCI 6251 and BNC 2110 that are available in my Lab. So, I want to use these hardware devices for my project which controls the induction motor drive system with the vector control method. For this, I need 6 analog inputs for gathering stator three-phase currents and voltages through a measurement board; and 3 digital inputs for gathering the motor speed through an encoder. Then, I use the vector control alogorithm as well as collected data in order to create 6 digital output signals for controlling the induction motor drive system. In summary, I will need 6 analog inputs, 3 digital inputs, and 6 digital outputs. Basically, the PCI 6251 and BNC 2110 can be used for this problem. But this is my first time that I use those devices. Otherwise, I never see any people who use them for controlling the induction motor drive sytem. So, I am quite confusing about this. If you have any experiences about this. Please, give me some advices.

Once again, thanks so much for your helps and supports.

Best regards,

Duy

[gt3000]

Hello Duy,

The PCI-6251 has the 6 Analog Inputs, 3 Digitial Inputs, and 6 Digital Outputs available for use, however, multifunction DAQ cards are not usually the standard device used to controls motors. 

In a motor control application, there are typical 3 components.  1) Motor 2) Motor Drive 3) Motion Controller Card.  I understand you have the motor, but do you have a Motor Drive?  A motor drive would most commonly be controlled by Motion control cards that have designed for that purpose.  This would ship with helpful drivers as well, which would benefit you in programming time.  Were you going to use LabVIEW to program the control, or another language?

When comparing Multifunction DAQ boards to Motion Controllers, it is important to not that a lot of the processing is done onboard the Motion card in terms of feedback and adjustment.  With a DAQ board, the acquisition rates would be fairly quick, however, depending on your programming, the data would have to be pulled into the computers memory and processed, before a decision is made for output feedback.  Click here to see what a motion application programmed in LabVIEW and NI-Motion would look like.

Regards,

[Duy]

Dear George,

Thank you very much for your reply,

Certainly, DAQ PCI 6251 card is not designed for controlling. I know about this, but we want to minimize the cost for our project with available devices. So, we want to use that card for this control. The induction motor drive system includes an induction motor and a DC motor as a load. Actually, we will control the induction motor with a load that is created from the DC motor.

We are going to use LabVIEW 7.1 to program the control.

Do you think we can do this with the obtained results which are good ?

Once again, thanks so much for your supports.

Best regards,

Duy

[gt3000]

Hi Duy,

The results you will obtain will have to compared to the ideal operation of the system.  The rate at which feedback will be considered and the output to the drive adjusted will depend on the update rate of the board, as well as the speed of the PC that will host this. 

As you already have the hardware, you may wish to try some examples to produce a system, but prepare for the situation where you might need to use Motion Cards and Software for higher performance results.

Regards,

[Duy]

Dear George,

Thank you very much for your opinions.

I am trying to control an induction motor with vector control method by using PCI DAQ 6251. I hope that I can get good results from this idea. But in order to have more options, could you give me the detail of the motion card ? (For example: What are the functions of this card ? Can it be used for controlling an induction motor with vector control ? and How much is it ? as more information as possible . . . ) 

Once again, thanks so much for your helps and supports.

Best regards,

Duy 

[gt3000]

Hello Duy,

It seems like you have further questions regarding pricing and exact model numbers to use for your application.  Standard practice is that these forums are used for technical support.  I invite you to call directly to your local branch and speak to an Inside Sales Engineer.  They will be able to guide you further.

To learn more about all LabVIEW examples, you follow the steps below:

1. Run LabVIEW

2. Navigate to 'Help'->'Find Examples'

3. Under the 'Browse' tab, navigate through 'Hardware Input and Output'->'Motion Control'

Regards,