Sampling data without a trigger

[rsmrostov]

I am using NI6225 wihtout a trigger to monitor loop back continiously

I have a loops  that continously measures the D+ and D- lines of RS485 loop back, when tehre's meaningfull data it is appended in a while loop by using tunnels->append option.  Everything works fine, however the are often two sampling intervals that the data occurs in, and when this happens the second interval gets appended to the beginning of the first, since the deltat is instituted automatically.  I have tried using the build waveform node to change the delta T by setting up a time stamp but it happens so fast, that both iterations come in with the same start time.

I had an idea of using the shift register and Append Waveform.vi, however this doesn't seem to work for me at all, as I can't initiazlize the input to the shift register properly...

Any help is appreciated.

[Tanner!]

Hey rsmrostov, will you help me narrow down where the issue is coming in to play?

Your daqmx task is reading correctly and producing the data you want, correct?

You are collecting data and a logical group comes through. However, sometimes the logical group gets split and the data is divided between two samples. Is that correct? Somthing like:

Send:
12345678

Recieve:
1     xxx12345

2     678xxxxx

Which then is appended and becomes 678xxxxxxxx12345 and you're trying to figure out how to maintain order when this event occurs.