How can i output signals to DAQ6009?

[jacks]

Hi friends,

      I am doing a project using LabVIEW... I am using DAQ6009 as the interface... The DAQ succesfully read the input signals which was properly processsed by the LabVIEW pgm... But I cannot output this processed signals through DAQ to the external hardware... Can any one suggest a solution to this problem???

[TroyK]

Perhaps you could provide some more detail on what you are trying to output to the 6009 device.

The 6009/6008 are very simple devices. They can read in data as waveforms at a specific rate, but they can not output data as waveforms at a specific rate.

They have some input buffering, but no output buffering. This means you can only output 1 point of data at a time.
If you want to output a waveform of data, you must bash it out 1 data point at a time and use software to time it's rate.

[jacks]

Hi Troy,

      Actually, I am doing a project to control the environment temp. using LabVIEW. I need to output the signals( which may activate a relay so as to switch on a cooler). But it only outputs one point of data at a time...

      Can you please tell me that how can I bash out one point of data at a time????

[ceties]

Hi, here is simple demonstration I wrote yesterday for students to show them some strain gauge measurements with DAQ6009. At first it outputs voltage value(to power the bridge) and then it reads input channel until you hit stop button. The part that you might be interested is marked by red. It's really simple. I also advice you to go through the examples shipped with LabVIEW. In case of 6009 remember that the output is limited to 0-5V. Cheers

Message Edited by ceties on 04-17-2008 06:54 AM

[TroyK]

'ceties' suggestion should work.

The only change I would make to the example posted would be to remove the 100ms timeout in the while loop and add a constant to the 'number of samples per channel' input of the DAQmx read vi in the while loop.

Then the timing is hardware controlled and you will get a consistent amount of samples out of the DAQmx read every iteration.
The read function itself will wait until the number of samples you requested are ready, then loop around.


Message Edited by Troy K on 04-18-2008 09:51 AM

[jacks]

Hi,

      I tried to create a VI as per your suggestions... But it still shows some problems... I am hereby attaching our block diagram... . we are using pid controller,.. the data read are controlled and should be continously outed....  Can you please check it and suggest necessary modifications so that it outputs data continiuously????