Where can I find info on Digital Acquasition

[057768022]

Thank's Sal.

I changed the file format and the "Port Read" format to binary, and I can see now the desired signals.

1. I would like to produce a *.dll file from my *.VI file and then call it from my MATLAB application.
How can I save the data to a variable and then call the *.dll, as a "COM" object form MATLAB?

2. My MATLAB file is analyzing the acquired data. My data signal rate is 1.4 Mbps. What is the amount of data that can
be analyzed in each "Hand Shake" Between the MATLAB and LABVIEW *.dll file using PCI - 6534? (In order to avoid overflow)

Best Regards,
Nir Corse

[Salvador_Santolucito]

Hi Nir,

If you are going to build your application into a DLL, you first need set up the connector pane for your VI.

In the front panel, right click on the icon for the VI (upper right corner of the window) and select show connector. Then, click the various boxes in the connector and then click on whichever controls/indicators you want to be passed to/from the VI. This is how you make a subVI. You could then place this VI in another VI and wire to these controls/indicators.

Then when you are going to make your .DLL click the "define VI prototype" button on the tab where you add the VI. In here you can add the controls/indicators that you earlier selected to the function prototype.

I have attatched a picture of what I'm talking about.

I am not sure how fast data can be returned to MATLAB. I would suspect that if the graph on your VI can keep up with the data, your VI dll would be able to return it fast enough. However, if MATLAB is doing a lot of processing it may slow down how much data you can transfer.

-Sal

[057768022]

Hello Sal,

I use the PCI - 6534 with the SCB-68 board.
I configured the LABVIEW program to external, using MAX I saw that the PCI detecs my signals.
I connected the CLK line to REQ1 in the SCB-68 board, when the data is acquired I can see that the SYNC signal
is not in the desired frequency (20KHz), I get ~ 28 kHz. When I use internal trigger I see all 3 lines at the desired frequencies.
Do to the fact that all 3 lines in internal mode are in SYNC, i can perform trigger function at software, but i would like to avoid it.

What can be the problem?

[Salvador_Santolucito]

Hi,

Hmm... It might be helpful if you could send me the newest code you are working on. What type of data transfer are you doing. I believe they have several different types of transfers listed in the 6534 manual.

http://digital.ni.com/manuals.nsf/websearch/EDE443F5C700373A862569B90072D26F?OpenDocument&node=132100_US


Are you referring to the SYNC line that is output from your board? Look through the timing diagrams listed in the 6534 help manual and let me know which type of transmission you are using. Also, some more detailed info about the device you are communicating with will help.

-Sal

[057768022]

Hi Sal,


I am using serial bus(SSI). The SYNC line is form my device (DUT) to the PCI.
The SSI include 3 lines in total: CLK,DATA, SYNC
I added a plot of the DATA and SYNC. In external CLK the SYNC is ~28 KHz instead of 20 KHz (Scope).
The CLK is connected to REQ 1 pin in SCB-68.
I am using the same simple LABVIEW program which I have sent you before.

Best Regards,
Nir

[Salvador_Santolucito]

Hi Nir,

Are you certain of the frequency of your external clock? If it is not accurate, the SYNC signal will look like it has the incorrect frequency. Basically, if you are expecting a 1 MHz clock signal that you are using to measure the frequency of SYNC but are really getting a 1.4 MHz signal, your SYNC will look like it has the wrong frequency when you measure it. Chcek the clock signal with the oscilloscope to verify its accuracy. How fast is it?

-Sal

[057768022]

Hi Sal,

My CLK signal is 1.4 MHz.

I added the OSC plot.
My CLK signal is in bursts, 48 pulses then 22 zeros etc.
When I am entering 1 MHz I get SYNC of ~ 20 KHz, but my CLK is ~ 1.4 MHz.

Best Regards,
Nir

[057768022]

Hi Sal,

My CLK is burst type, 48 CLK and 22 zeros. My effective clock frequency is : 48/70 * 1.4 MHz = 0.96 MHz.
Now is works fine.

I also set DIO Config to active low as written in PCI - 6534 manual. (External REQ settings).

I added my new plot.

In the DATA port I have bursts of 70 bits, how can I extact those bits to a buffer in LABVIEW?
I need to translate the bits to decimal format.

Best Regards,
Nir

[Salvador_Santolucito]

Hi Nir,

There are several data conversion VIs in LabVIEW. Check them out.

I have attatched a picture of how to find them.

-Sal

[057768022]

sal,

I have an array of size [8000 X 16]. I would like to change each raw to it's 2's complement form.
Is there a fast way to do it in LABVIEW?

Best Regards,
Nir Corse