PCI-6534 High speed signal output

[Ayumi]

Dear all,

I am trying to make an output signal with PCI-6534 with highest frequency possible. Is there any suggestions or sample vi that I can try with?

I have been trying to use the vi in the examples (e.g. Dig Buff Hand Interactive, Buff Handshake Output, Burst Mode Output, etc) but there is no signal detected. Does PCI-6534 support buffered handshaking? If yes, what should I do?

Thank you for your attention!

Ayumi

[Marni]

Dear Ayumi,

To achieve the highest frequency, I recommend using Burst Handshaking. There is an example that comes with LabVIEW that I recommend trying. Go to Help menu>>Find Examples. Browse Hardware Input and Output>>DAQmx>>Digital Generation>>Cont Write Dig Chan-Burst.vi. In the Example Finder, under Description, there are step by step details of how to set up the hardware. Follow those instructions and see if you get a signal.

I looked in the PCI-653X User Manual and found the following tips for obtaining the fastest transfer rates:

• Burst mode is the fastest handshaking protocol. You can further increase speed by using short cables.

• Finite transfer is faster than continuous transfer.

• Minimize the number of other I/O devices active in the system. Your system bus should be as free as possible from unrelated activity.

• DMA transfers are faster than interrupt-driven transfers, especially for pattern I/O. On the PCI-6534 the software uses DMA transfers by default.

Please let me know if you have any questions. Have a great day!

Sincerely,

Marni S.

[Ayumi]

Dear Marni,

Thank you for your reply!

I have tried burst mode by connecting one of the ports with a CRO but there was no signal seen on the CRO screen. Do I need to connect a particular port or line in order to use the burst mode?

And I have no idea on how to use Direct Memory Access and there is no information about it in the LabVIEW bookshelf...I don't know what to do with it...

Ayumi

[Marni]

Dear Ayumi,

I thought of a better way to output digital data on a PCI-6534. You can use onboard memory and Pattern IO to achieve rates up to 20 MS/s, the same as burst mode handshaking but much easier. In the Example Finder browse Hardware Input and Output>>DAQmx>>Digital Generation>>Write Dig Chan-Int Clk-Dig Start.vi. You can take out the Digital Trigger if you want. Insert a Channel property node before the DAQmx Write VI. Select the property Use Onboard Memory Only to true. Please let me know if you still have trouble outputting data. Have a great day!

Sincerely,

Marni S.

[mlloyd]

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@Ayumi wrote:

Dear Marni,

Thank you for your reply!

I have tried burst mode by connecting one of the ports with a CRO but there was no signal seen on the CRO screen. Do I need to connect a particular port or line in order to use the burst mode?

And I have no idea on how to use Direct Memory Access and there is no information about it in the LabVIEW bookshelf...I don't know what to do with it...

Ayumi

---

Ayumi,

Just out of curiosity, what's a CRO?  I've used the 6534 in burst mode but didn't understand your test setup...

Have you set your board configuration?  Some parameters I always use are PCLK source (internal or external), handshake direction (inverted or regular), and port direction.  You might be writing to port 0 and reading from port 1, for example, which would mean you wouldn't see the signal you're generating.  I don't have the name of the configuration VIs in front of me, but maybe that helps some...

Regards,

mlloyd

[Ayumi]

Dear Marni,

Thank you for your reply!

I am using LabVIEW 6.1. DAQmx cannot be used with LabVIEW with version lower than 7.0 right? I think that is why I could not find the folder DAQmx in the examples.

Ayumi

[Ayumi]

Dear mlloyd,

Thank you for your reply!

By CRO I mean Cathode Ray Oscilloscope. I want to see the signal output directly so I used a CRO. I am not sure if setup like this has anything wrong. Please point it out if there is anything wrong with the setup.

Ayumi

[mlloyd]

Ayumi,

My experience with burst mode handshaking with the PCI-6534 is similar to the examples "Burst Mode Input.vi" and "Burst Mode Output.vi".  In 7.1 they are located under

Examples --> Hardware Input and Output --> Traditional DAQ --> Digital Input and Output --> 653x

If your version of LabVIEW isn't organized in the same way, perhaps you could search for the VI name.

When you configure the 6534, keep in mind that if the PClock source is set to external, the card will wait until it sees an external clock before outputs data.  It sounds like for your application you want the PClock source to be internal.  Other than that, check that the ports you set in the port list for output include the particular channel that you will be viewing on your scope.  You could set all ports to be output, so your port list would be 0,1,2,3.

Hope this is of some help if you decide to go with burst handshaking mode!

Regards,

mlloyd

[Marni]

Dear Ayumi,

There is an example on ni.com called Continuously Generating Repeat Data from Digital Output Channels (Loop From Onboard Memory) uses onboard memory in Traditional (Legacy) DAQ. Have a great day!

Sincerely,

Marni S.