update amplitude while running labview

[Jason_Chan]

Hi Otis,

Thanks. I am sorry that i cannot use the program because i am using a PCI 6120 S-series. Can you advice me further. Thank you.

Best wishes. Chan

[Otis]

Sorry about the confusion.

The example should work fine with the 6120 also.  Even though they are different pieces of hardware, the software remains the same...that is the beauty of DAQmx.

[Jason_Chan]

Hi,

I try to use the software given by Otis (attach below) and i am using PCI 6120 and SCB-68. My problem is that i cannot find the AO Ext Ref. I need to connect AO 0 to AO Ext Ref. Please advice me. Thank you.

Best wishes. Chan

[Otis]

Hi Jason,

I think I found out the solution to what's going on.  With the NI 6120 (which you have) evidently you cannot use the External Reference like I originally thought.  That functionality is supported in M and E Series boards, but not by S Series boards.

Fortunately, according to this old post you'd be happy with being able to have a relatively quick solution, as opposed to having to wait for about 10 seconds for the buffer to clear out like you did in the Non-Regeneration example.

Essentially, the only solution that will work here is to use the Non-Regeneration Example, and then add something called a property node (you can just drop and drag the current one), and add the AO.DataXferReqCond and set it to Onboard Memory Empty.  That will allow you to only transfer data when you need to and will allow you to more quickly change the buffer in memory.

If you run into any further problems, let us know AND let us know what values you are using for the various controls.

Regards,

[Jason_Chan]

Dear Otis,

I have run the program you sent to me. I didn't change any value in this program. I face some problem. The waveform generated is not constant, sometime the amplitude is high and sometime is low. Please view the attachment. I also change the ampltiude value while running the program, but the amplitude still didn't change. Please advise me. Thank you.

Best wishes. Chan

[Otis]

If you look at the program you can see that I stuck in a function to get it to constantly be changing amplitude.  If you don't like that, then simply stick the Amplitude control in the loop, delete the sign wave portion and it will only change when you tell it to.