keithley 3116 -labview link

[nolsqn]

hey hi

 i am trying to get data out from keithleys kusb 3116 daq card . kheithley provides labview link for there cards.well i am really new at this and i need to get the data out from one pc and send it to another..at one pc a vi generates the data and at the other pc a second vi receives the data ???

[G_Lo]

nolsqn,

I believe that you are referring to the DT-LV Link software.  Here is a great link that shows the corresponding functions of DT-LV and Traditional DAQ VIs.  To attain the data from your Keithley 3116 you will have to structure your code similar to that of a Traditional DAQ example.  These examples can be found by selecting Help>>Find Examples and then select Broswe according to: Directory Structure.  There should be a folder called daq and this will contain all the example programs.  The program that you base your architecture on will depend on the type of acquisition that you would like to accomplish.  Also, this DT-LV software looks like it is only compatible with Windows 95/98/NT/2000.  You said that two pcs will be involved in this process and they will send data between one another.  Could you explain this a little bit further. 

[nolsqn]

hey G lo

well basically what i need to do is to perform OFDM between two pc........ i have created  a simulation of ofdm on labview... wat i need to do is that establish TX one one pc and RX on the other ...that also i have done ....now what i need to do  is that  estalish a lik between them using the keithley 3116 .........{using 3116 is the only option because well they are only daq available to me }.......if u want i can send u the VI's also ?

thnx

[G_Lo]

nolsqn,

By OFDM between the PCs I am guessing that you are modulating some signals on different carrier frequencies on PC1, adding these signals together on PC1, sending them to the input of the Keithley device and use the second pc to process the data.  The only reason I mention modulate is that OFDM (Orthogonal Frequency Division Multiplexing) is typically utilized in RF applications.  I am still unclear, though, as to where the data is coming from on PC1 and how the Keithley device will play into this.  Could you utilize some kind of serial connection between the PCs for this as well?  If you would like to accomplish what I had stated earlier then you could utilize the VIs that I had mentioned in my previous post to read the data from your Keithley device to process it in LabVIEW.   

[nolsqn]

G lo , u are right by saying "modulating some signals on different carrier frequencies on PC1, adding these signals together on PC1, sending them to the input of the Keithley device and use the second pc to process the data.". well ofdm is used in rf applications but i dont have any rf tool to transmit data the only option i have is to use daq card and show just the concept .the data is coming from the first pc1 ..the pc1 well be acting as the transmitter and pc2 as receiver ...so what i need to do is to use two daq card ..get pc1 to transmit the data and pc2 to receive.... but i dont know how to the daq card ...what are the analog output for or digital..should i be getting the data out from the analog or digital .....

[G_Lo]

nolsgn,

I am not sure on all of the details for the Keithley 3116 but I imagine that you would want to have PC1 outputing an analog signal and PC2 reading that analog signal.  You will have to physically connect the two analog channels of the cards together and program PC1 for analog output and PC2 for analog input.  There are analog output and analog input functions which are pre-written for your device.  As I had stated in my previous post, VIs have been written to map to our Traditional DAQ VIs.  You could base the architecture of the analog input and output off of our Traditional DAQ examples which you can find by selecting Help>>Find Examples.  Select Browse according to: Directory Structure and the examples should be in the daq folder.  Also keep in mind that you only have 4 analog output channels on your card.  More detailed information on your card can be found in the manual, though.

[nolsqn]

G lo,

well u said i should get analog output from one pc ....well at the end of the processing of ofdm in pc1 that is the modulator the output is an array of complex ....attached here is the vi ...plz have a look and tell me how i cam send the data on to a daq card

[Raajit_Lall]

nolsqn,

It sounds like you already have the OFDM protocol taken care of on the software side of things and now you are only trying to establish some kind of communication between two of these DAQ boards?  Please correct me if I am wrong.  Some questions that I do have for you are what is the carrier frequencies that you are running at, and how many channels are you trying to TX and RX on?

Have you been able to use any kind of example programs to establish any communications between the two boxes.  Gio posted a link to the DT-LV link, is that the software that you are using for this communication?  If that is the case, then some of those example programs should help you to establish communication between the DAQ boxes that you have. 

I also took a look at your VIs and it looks like you are using the Modulation Toolkit to create your OFDM signal.  Once you do this, the data that will be created will actually be analog data, which you can then write to the analog channels of the DAQ board.  Now, I also see that you have a bitstream to which you are applying QAM modulation.  At this point, it depends on what kind of communication you are trying to acheive with the board.  Something to keep in mind is the symbol rate, etc that you specify for the OFDM signal that you are generating, since that will affect your carrier frequency etc.

Although it looks like you already have the OFDM signal taken care of, here is an example, which should help you anyway.

That being said, if you do want analog outputs, which will probably be the easiest for you after looking at your code, you should be able to use the basic DT-LV examples (see Analog Output) example to output your values.  You already have the values in software so you can just feed those to the analog output using the example code.

Hope some of that helps.

Regards,

[nolsqn]

RAAJIT.

yes i want to establish a comunication  link b/w daq cards....well as you can see from the vi that i have only done the baseband modulation ....we dont have any carrier wave ...and welll i dont know how to use carrier if u can help me in this regard ...you also said that the output is analog data ..but what i see is array of complex numbers...how this is analog????.....yes i have used the examples of the DT-LV  and have establish link between daq cards... well if i can have an analog output at the end of the tx i can daq card to send it out to the other daq card but what i cant understand is how i can use an array of complex number to be transmitted as an analog signal.....i looked at the ofdm example ....well i must say it is any very defficult to understand the programing behind it .....also why pluse shaping  is required??

thnx