What is the difference between ni-daq and ni-visa?

[NickFox]

What is the difference between ni-daq and ni-visa?

thanks
Nick

[Dennis_Knutson]

NI-DAQ and DAQmx are API's (application program interfaces) for programming NI's (and only NI's) data acquisition boards. VISA is an API that is specified by the VXI Plug & Play Systems Alliance. Originally designed to give users a common API for programming GPIB and VXI instruments, it has since been expanded to include support for serial, USB, Ethernet, and PXI instruments. If an instrument driver is written with VISA calls, it will work for any of the interfaces and with any vendor's implementation of VISA.

[lolasue]

I am receiving ascii data from a usb connected device. I need to analyse the data. Should I be using DAQ or  Serial Visa vi? I have already set up the communication on basic serial visa vi and I can see the data. But when i look into labview data analysis tools, the solutions refer to DAQ. Can DAQ also work for serial communication?

[Alexander_Sobolev]

DAQ and VISA are for getting data from hardware. If you have received data, you do not need hardware interface anymore. You need software tools to convert your data (number of bytes) into meaningfull information (sensor values). The data format (conversion rules) should be in your device manual. If we know the format, we can advise how to write a converter, it is usually straightforward.

[lolasue]

Hi Alexander, my device is a sensor protégé board. The date is sent in ascii format. I need to convert this data to voltage values and then convert that to sensor output ie temperature and then see it as a waveform. Is this possible with Labview?

[lolasue]

Sorry that Shud read a "prototype ' board

[crossrulz]

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@suzanneocallaghan wrote:
Hi Alexander, my device is a sensor protégé board. The date is sent in ascii format. I need to convert this data to voltage values and then convert that to sensor output ie temperature and then see it as a waveform. Is this possible with Labview?

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Yes, it is possible.  I recommend you start a new thread and give a lot more information.  What interface is the board using to send the data (serial, usb, ethernet, etc)?  What is the format of the data that is sent to you?

[Alexander_Sobolev]

If you already have a string, where you see voltages, try spreadsheet string to array. Set correct delimiter, numbers format.

Then you have Numerics -> Scaling palette to convert array of voltages into temperatures, depending on your sensor type

Then you display result on a waveform

[rolfk]

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@lolasue wrote:

I am receiving ascii data from a usb connected device. I need to analyse the data. Should I be using DAQ or  Serial Visa vi? I have already set up the communication on basic serial visa vi and I can see the data. But when i look into labview data analysis tools, the solutions refer to DAQ. Can DAQ also work for serial communication?

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There is no simple answer to that question. USB can mean many things! It's the physical transport layer for communication, but the protocol that is transported over the USB cable can be many things. There are specific USB protocols for connecting to mass storage devices, human interface devices such as keyboards, mice, etc, devices which appear as serial communication devices, and even a special class that appears as measurement device very similar to a GPIB device. Last but not least every vendor is free to invent his own protocol too which many do, for whatever reasons including to simply be different than the rest.

VISA supports raw USB and the measurement class device and through Windows the serial communication class device. Your device certainly won't be a measurement class device, that is only used by companies like Agilent/Keyseight, Keithley, etc. It may be a serial communication class device but that is not sure. If it is anything else you either have to use VISA USB raw, which requires you to implement the entire low level USB protocol handling too and is only an option with a thorough protocol specification which is usually very difficult to get at or you have to get a DLL from the vendor and interface to that DLL through the Call Library Node in LabVIEW.

[sagray3rd]

"Hi Alexander, my device is a sensor protégé board. The date is sent in ascii format. I need to convert this data to voltage values and then convert that to sensor output ie temperature and then see it as a waveform. Is this possible with Labview?"

Yes

this is a pretty basic operation for Labview assuming that you can get the ascii data stream into LV with a suitable DAQ VI.

I know this is old but this is basically what LV was made for.