Where does t0 come from in the cDAQ waveform output?

[Blueprint]

Dear Community,

I am working on a system using timestamping of data on various network devices. They are divided into critical (FPGA controlled) and non-critical (cDAQ waveform) timed data.

I am using a NI9181 cDAQ with NI9205 for logging analog signals on a remote location. I am programatically setting up tasks and reserving chassis and all the necessary stuff.

When I am reading 100 samples each second, I get a waveform output with Y, t0 dt and attributes as we all are familiar with. But my questions are:

Where does the t0 come from? After some testing, it seems like the time is taken from the local PC clock, is this correct? So to get accurate timing (within 0,1 second since it is non-critical) I need to sync the PC clock to mye GPS? When is t0 set? when I start the task? Ive tried to navigate into the VI I use (DAQmx (analog 1D waveform NChan NSamp).vi but I dont get longer than the nilvaiu.* dll call.

I am thankful for all comments and help:)

Cheers,

Øyvind

[Izzzzz]

Hello Øyvind

Please take a look at this KnowledgeBase Article which discuses where the t0 is coming from.

Regards,

Izzy O.

Applications Engineer

National Instruments

www.ni.com/support