create voltage over time

[pnielsen@gplains.com]

Is it possible to generate an output voltage on a DAQ 6009 A0? I have an excel data sheet that I have put into a 2D array. The voltage is not constant over time. I am having difficulty with the timing of the signal. I have been able to plot the signal on a graph. It is the same as the original data from excel. I have the two streams of data. Voltage and time. But after seperating the two signals how can I generate the graph?

[aeastet]

You are kind of all ove rthe place with this question(s).

Yes you can generate a voltage with 6009 AO.

You could plot the data in an XY graph and get voltage vs time or you can send it to a wavefore graph and set the properties to absolute time. There will be some conversions for this I would expect.

If you post your code we can help more.

[Dennis_Knutson]

Of course you can use the 6009 to generate a voltage. It has 2 analog outputs that go from 5 to 5V. Since it's software timed, your update rate is pretty slow and you can see in the specs.

[pnielsen@gplains.com]

Thanks for the feedback. I am trying to output a different voltage to A0 on a DAQ 6009. My time interval is around 100 mS. I have enclosed the excell data sheet and the VI

[aeastet]

you forgot the attachments

[pnielsen@gplains.com]

OOPS

[aeastet]

I got your VI's. Are you trying to generate a voltage that matches the XLS file that you attached?

[aeastet]

Here is your data graphed Voltage vs Time. Are you trying to fix the voltage to be a straight line? If so what are you out putting to? How much current does it draw? Are you trying to control with a PID loop?

[pnielsen@gplains.com]

I am trying take the excel sheet and create a voltage that is an exact duplicate of our custumer's graph. I have been able to output the voltage at A0 but there is no real time involved as yet. This voltage goes to pressure valve. The enclosed file is the file I am trying to create. The voltage will drive the valve open. It is a 4 to 20 MA servo valve. The time versure pressure is criticla.

Philip

[Dennis_Knutson]

If the time is critical, why did you choose the 6009?

It's pretty straight forward to create an array of dt values from the time column. This dt array and the voltage array would be wired to a DAQmx Write and Delay function inside a for loop. So there would simply be a write and a specified delay before autoindexing a new set of values. However, since all timing is controlled by software and windows is not anywhere close to deterministic, you will have significant jitter. Can you live with the time being off by 10s and sometimes 100s of milliseconds?