Timestamp of trigger?

[bobausttex]

I have a DAQmx device taking fixed samples,, on a digital edge, triggered by PFI0 and I can not find how to know or read T0  the exact time of the first sample. 

Is there a way to read or make a time stamp of the first sample?

PXI 6115

or

PXIe 6368

[RavensFan]

Isn't the T0 in the waveform that the DAQmx Read returns?

[Kevin_Price]

The answer from RavensFan is very likely all you need.  The initial T0 gets calculated the first time you read from your task and it takes into account:

- the "right now" time that the read is happening

- the actual sample rate

- the # of samples read

There are certain fairly unusual cases where this estimate isn't quite good enough, but let's not assume you have one of those unless you provide more details to indicate otherwise.   More info here.

-Kevin P

[bobausttex]

We are reading an unscaled Analog 2D, I32, Nchan, Nsamp.  I have never seen waveform data in that.  Is there a way to get it or is it there and I don't see it?

[RavensFan]

It is in the polymorphic selector.

[bobausttex]

I can't just change what I am reading to get t0.  I need t0 for what I AM reading.

[RavensFan]

But you can't get that t0 when you are using a raw, basic setting on your DAQmx read that doesn't provide t0.

You certainly can change what you are reading so you can get t0.  Why do you say you can't?

What made you pick "unscaled Analog 2D, I32, Nchan, Nsamp" to begin with?

[bobausttex]

I have been supporting this program since like 1994.  I started learning Labview for fun on ver 2.5 I think.  I have an expired CLAD but am not a programmer.  I just do it.

I am retired and putting my programming days behind me.  This program has seen 4 different A2Ds and it is what it is.   Over 168 sub vis and over 900 total called on launch.

The T0 use to come from the Unix system and the VME rack we used in the 90s.  When we went to PC and PXIe I just read the data type in that was needed to match.   I could change it but I am not wanting to do that.   If there is no other way then they can live with the time stamp I make as the data comes out of read.  No one has noticed in 5 years.

[bobausttex]

Best I can tell this is not resolved.  I need the data output I need.  It seems like a read from any a2d ever made should give you access to T0 somehow.  

[GerdW]

Hi bob,

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@bobausttex wrote:

It seems like a read from any a2d ever made should give you access to T0 somehow.  

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DAQmx does provide t0 once you switch to "waveform" output.

It's you who sticks to "unscaled integer data"…