6534 burst data

[zoran]

I want to simply send 200 bytes continuously in burst mode from 6534. No handshaking, no external clock. Where I can get this example?

Thanks,

Zoran

[Wallace_F]

Hello Zoran,

I understand that you would like to find an example program to generate 200 bytes in burst mode with no handshaking and no external sample clock.  However, burst mode is a type of handshaking according to how we use the term burst mode. Perhaps, you could explain in detail what you would like to see for the behavior of the digital output relative to your digital output timing source.  This would help those of us who read this post understand more explicitly what you are looking for.  In the meantime, I did find an example for the NI-6534 that generates digital output in burst mode, continuously. You can find the example by performing the following steps:

1.  Open LabVIEW and select Find Examples.

2.  In the NI Example Finder, select Browse according to: Task.

3.  Open the Hardware Input and Output folder.

4.  Open the DAQmx folder.

5.  Open the Digital Generation folder.

6.  Select the example called 'Cont Write Dig Chan-Burst.vi".

If you are programming using the C API, you can find the example in the following (or a similar) location in your directory structure:

C:\Documents and Settings\All Users\Documents\National Instruments\NI-DAQ\Examples\DAQmx ANSI C\Digital\Generate Values\Cont Write Dig Chan-Burst

Best wishes,

Wallace F.

[zoran]

I have to send identical 200 bytes from internal buffer every 2 milliseconds out - and perform read between when these 200 bytes are sent out and next 2 milliseconds tick. Can I keep these bytes in 6534 internal buffer and send it when I want, not when some trigger occurs?

In your example data is continuously sent out and there is no any way to stop it by software, what is what I have to do. 

Thanks,

Zoran

[Wallace_F]

Hi Zoran,

You can keep the 200 bytes in the onboard memory of the 6534 digital I/O card by including the DAQmx Channel property node and selecting the Digital Output >> General Properties >> Advanced >> Data Transfer and Memory >> Use Only Onboard Memory property, and wiring a true constant to the input node of the property.  You would also have to implement the DAQmx Write property node to allow regeneration mode by placing a DAQmx Write property node in your task and selecting the Regeneration Mode property. You would then have to create your 200 bytes of data and write it to the devices onboard memory by wiring the data to the data input terminal of the DAQmx Write VI.  There is a Developer Zone article that has example code that illustrates how to continuously write a digital pattern from memory. 

The example code writes the data continuously, but does not implement any of the timing that you want.  You would have to modify the code to implement the timing that you want.  I understand that you want to write the data when you want, but can you explain how you will tell the driver to write the data?  Also, are you using just one line to output the 200 bytes of memory, or are you using multiple lines on one port?

Best wishes,

Wallace F.