Trigger and Offset problems with PXI-5124 (12bit ADC)

[CongThien]

Hello,

I have been working with the 12bit ADC, NI PXI-5124, for a few days and I found some problem that I do not see in the datasheet. I want to record the waveform from 0-4V so I set the Vertical Range =4V, and the Vertical Offset=2V.

1. The trigger value that I set is different from the actual trigger executed in the ADC. For example, when I set the trigger is 0.05V, I found out by using the generator is that the actual trigger is 0.1V. For every trigger value that I inputed, the actual trigger = input trigger + 0.05V. Why it is happening like that?

2. When I set the trigger is 0 the actual trigger is 0.05V. The signal high that I received from the ADC is different from the signal high of the generator when the signal high from the generator is smaller than 0.1V. For example, when the generator provide the signal high is 0.06V the signal high that I received from the ADC is around 0.07V. Why there is a mismatch between the signal high of the ADC and the generator when the signal high under 0.1V? (4V Range, 2V Offset)

I would be very grateful if someone give me some advise.

[JKarma]

Hello CongThien,

I'm very interest in this phenomena can you please share a portion of the LabVIEW code and if possible the full context of the scenario. This in order to find possible causes.

[CongThien]

Hello Jkarma,

The attachment is the program that I am using for the data collection. I am preparing the PXI-5124 to read the output singnal from a HPGe detector. I want to open a window 0-4V with max Dynamic range so I setup the ADC with 4V Vertical range and 2V Offset. I am investigating the trigger and I met the Problem that I mentioned.

I would be very grateful if you can help to explain. Actually it would be fine if I just set the Trigger from 0.1V and higher, but I want to know the reason of the mismatch of the signal below 0.1V.

Thank you for your treasure time.

Cong Thien