Does Motion Control card support continuous acquisition similiar to DAQ

[SudhaBalayanan]

Hi All,

I am using PCI 7352 Motion Controller card for servo motor control. Speed and torque are the parameters i control and measure.

Apart from the finite measurement that encoder gives,  i need to plot speed and torque at certain sampling rate.

I was wondering whether motion control card supports continuous acquisition similiar to DAQ card. I did search in NI site and looks like it is not possible. I need to go for an additional DAQ card to do this. Is my understanding correct.

Thanks,

sudha

[Jochen]

Sudha,

with the 7352 you could acquire position data with a rate of up to 2 kHz. Please have a look at the High-Speed-Capturing examples to learn more about this feature. Still you would need an external clock signal for this operation and there is no good option to do a contiuous acquisition for torque values (analog signals).

So there are some limited options to do buffered acquisition operations with a 7352, but in general a DAQ board provides much better data acquisition capabilities.

Kind regards,

Jochen Klier
National Instruments

[SudhaBalayanan]

Jochen Klier,

Thankyou for the reply. I did study the motion controller and understood that to synchronize Speed and Torque data, we need to use Motion controller card (for speed data) and a DAQ card (Torque data).  Hope i am correct on this.

To Acquire Speed data:-

• I read through the Buffered High capture examples. My tests require two types of speed data

                 1. When the Speed is gettting accelerated.

                 2. After the required speed is achieved , i want to acquire data for certain revolutions. 

 Please let me know the order in wich i should configure the speed control vi and buffered acquisition vi to acquire data and achieved speed control.

• Are there possibilities to do buffered speed capture at 2 Khz for a certain duration. Something like i start the acquisition at start of first test and end the acquisition after all test complete. On looking at the examples it is looking like we can acquire certain number of speed points only.  
• Also are there possibilities to connect this encoder output (speed data) to an DAQ card. If that is possible i can do speed control using motion controller and acquire torque and speed using DAQ card.

Regards,

Sudha

[SudhaBalayanan]

Jochen Klier,

Thankyou for the reply. I did study the motion controller and understood that to synchronize Speed and Torque data, we need to use Motion controller card (for speed data) and a DAQ card (Torque data).  Hope i am correct on this.

To Acquire Speed data:-

• I read through the Buffered High capture examples. My tests require two types of speed data

                 1. When the Speed is gettting accelerated.

                 2. After the required speed is achieved , i want to acquire data for certain revolutions. 

         Please let me know the order in wich i should configure the speed control vi and buffered acquisition vi to acquire data and achieved speed control.

• Are there possibilities to do buffered speed capture at 2 Khz for a certain duration. Something like i start the acquisition at start of first test and end the acquisition after all test complete. On looking at the examples it is looking like we can acquire certain number of speed points only.  
• Also are there possibilities to connect this encoder output (speed data) to an DAQ card. If that is possible i can do speed control using motion controller and acquire torque and speed using DAQ card.

Regards,

Sudha

[Michelle_N]

Hi Sudha,

To answer your first question: yes, this is one way of doing control and measurement (with a separate motion controller and DAQ card). You will want to synchronize the two cards using RTSI.

You do not have to configure speed control and buffered acquisition in any order, you can do it in parallel. This is the beauty of LabVIEW.

Yes, you can do a buffered high speed capture for period of time. Although, the buffer high speed capture was not necessarily designed with this in mind, it is possible. This is all matter of finding a way that will work for your application. One way might be to break up your finite period into small-equal amount buffer read/write sessions. Start by making the buffer a reasonably small size. Write to it, fill it up, and read the buffer. Then repeat for the number of iterations needed to complete the period.

It is possible to pull encoder data into a DAQ device but not necessarily the most desired thing. If you can keep encoder acquisition on the motion controller the setup will be simpler. Once again, you would want to do this with RTSI. This is all depends on your setup – what kind of motor and drive are you using?