topic Re: waveform generator in LabVIEW

waveform generator

Roxanne — Wed, 10 Aug 2011 02:21:06 GMT

Hi,

I am using a 6551 waveform generator, generating on 14 outputs and simultaneously capturing on 6 inputs. All of a sudden all captured waveform are zero, I tried restarting LabView, and later restarting the computer, seems the card does not seem to capture anything.

Any ideas as to what might have gone wrong?

Thanks

Re: waveform generator

simply_me — Wed, 10 Aug 2011 06:01:37 GMT

Hi Roxette,

Did you look into MAX (Measurements and Automation) to see if the card is still defined there?

Re: waveform generator

Roxanne — Wed, 10 Aug 2011 20:12:23 GMT

Yes, the card seems to be working fine according to MAX. I am using an example for simultaneous generation and acquisition from NI:

Dynamic Generation and Acquisition-Demo.vi

with minor changes:

1) Using an .hws file to generate waveforms as opposed to the waveform created in this example VI.

2) Using different sets of channels for generation and acquisition.

However instead of the clock that I am generating (and routing to an acquisition channel for test) I am getting flat lines.

In other words it seems the card triggers once only.

I have tried "Pattern to Match" of all 'x' instead of 0 or 1. Same issue.

Re: waveform generator

simply_me — Wed, 10 Aug 2011 20:20:42 GMT

Have you tried to generate the signal in a loop?

Can you post a picture of your block diagram?

Re: waveform generator

Roxanne — Wed, 10 Aug 2011 20:56:58 GMT

Re: waveform generator

simply_me — Wed, 10 Aug 2011 21:03:43 GMT

So, you should setup the connection before a while/for loop (e.g. create channel), acquire the signal in a loop (get signal), and then stop and clear signal. That's the general schematics you should follow.

As it is now, you only acquire N samples once.

Re: waveform generator

simply_me — Wed, 10 Aug 2011 21:06:22 GMT

For example, I did this vi yesterday.it's a basic vi to adjust gain, but it follows the same structure- initialize, acquire, close/clear

Obviously, if you want more features such as save file you should decide if you want to do it in the loop or out of the loop, etc.

Re: waveform generator

Roxanne — Wed, 10 Aug 2011 21:22:30 GMT

So, generating the channel for acquisition and the acquiring data has to be in a loop? But if the intention is to generate and acquire at the same time, then both generation and acquisition have to be in a loop.

Do you have any examples for HS-DIO that you can send me please?

Re: waveform generator

simply_me — Thu, 19 Mar 2026 18:17:01 GMT

No, you want to generate a channel/initialize out side of the loop in most cases. Just like I did in my vi-- created 2 channels outside but read them inside the loop, and stop-clear when done outside of the loop.

Is this example helpful? http://zone.ni.com/devzone/cda/epd/p/id/2963

Re: waveform generator

David-A — Thu, 19 Mar 2026 18:17:57 GMT

Hi Roxette,

You may want to take a look at the our Getting Started with NI-HSDIO. Hope this helps!

David A.

Re: waveform generator

Roxanne — Thu, 11 Aug 2011 16:54:42 GMT

Hi David,

I have read that introduction. What I cannot figure out is when playing an .hws file on the card as opposed to 1D arrays generate din NI examples, I can see the .hws signal on the output and the also on the acquisition channel (physically routing a signal for test). But somehow the acquired data always look as N samples of one value (0,1), I am using a slightly modified NI example, for simultaneous generation and acquisition.

I have tried using "Multi Record: WDT" but still the same issue.

Any idea?

Thanks for your help,

Roxette

Re: waveform generator

Roxanne — Thu, 11 Aug 2011 17:49:42 GMT

Seems all programs work fine once I shut down and restart the computer (NI card issue?).

Re: waveform generator

David-A — Mon, 15 Aug 2011 23:09:52 GMT

Hi Roxette,

It may be an issue with the card. There may have also been an issue with properly clearing the resources. Regardless, what platform was this card for?

David A.

Re: waveform generator

Roxanne — Mon, 15 Aug 2011 23:30:40 GMT

Hi David,

This is on Windows7.

Roxette

Re: waveform generator

David-A — Mon, 15 Aug 2011 23:34:39 GMT

My apologies. I meant is the 6551 a pci or a pxi card?

David A.

Re: waveform generator

Roxanne — Tue, 16 Aug 2011 01:29:24 GMT

It's a PCI.

Re: waveform generator

David-A — Tue, 16 Aug 2011 18:22:28 GMT

So I don't think this is an RMA, but if the behavior happens again try reseting the device in MAX. You can also try running examples if it happens again to see if the results are as expected. If the issue persists you may need to post some more detailed information on how you have the card connected.

David A.