I have a NI-5186 data acquisition module that I am trying to use in 2 channel mode. My signal will have a trigger every 1ms and I want to collect measurements for 100 seconds or more. I want to sample at 6.25GS/s and to be able to get as many samples as I can. The NI-5186 is in a PXIe-1078 chassis with a PXIe-8102 controller. I am running LabVIEW 2011.
I originally tried using the NI-Scope examples using the HWS examples without much luck. I have more success using TDMS, which my example code is using. I have run into several questions I was hoping you could help on.
- With samples set at 125K and records set at 4K, the data looks correct. When I view the TDMS file the records 1 – 41 are empty, records 42 – 4041 look correct and the final records 4042 is empty (See TDMS_Errors.png). What is going on?
- I have not tried reading the TDMS file back, except for the viewer.
- I realize there is limit to the maximum sample size, limited by the 250Mb/s bus of the PXI chassis.
- My record size appears to be limited. If I set my record size to be 5K then I get the following error (see below in gray). What limits my record size?
- How do I set things up to read, for example 100K records?
- How do you decide how many records should be fetched at a time?
Thank you.
Error -1074116198 occurred at niScope Multi Fetch Binary 8.vi:3
Possible reason(s):
Acquisition has been stopped to prevent an input buffer overwrite. Your application was unable to read samples from the buffer fast enough to prevent new samples from overwriting unread data.
To avoid this error, you can do any of the following:
1. Increase the size of the buffer.
2. Increase the number of samples you read each time you invoke a read operation.
3. Read samples more often.
4. Reduce the sample rate.
5. Reduce the number of applications your computer is running concurrently.
In addition, if you do not need to read every sample that is acquired, use the Relative To and Offset properties to read the desired samples.
Status Code: -200613
