Acquire a serial analog dataflow

[Spadacar]

I need to acquire a serial analog dataflow (1Ms/s) from a linear sensor by means of USB 6251 multifunction board.
My sensor outputs are:
-data clock (TTL digital)
-first data line marker (TTL digital)
-analog sigrnal

I want to acquire a lot of  lines without losting any.
I can't use successive N data acquisition because software start is non so fast.
I can't use continuous acquisition because  I can't identify real first line datain case it lost any data.

Is it possible to syncronize analog and digital acquisitions and build a 2 columns data array (column1: analog data; colummn2: digital data) without syncronization error delay, etc.?

Bye
Carlo

[JordanRandall]

Greetings Carlo,

I'm assuming you are using LabVIEW 8.0/8.20?

Yesterday I was synchronizing Analog and Digital inputs with one of our shipping examples:

Help >> NI Example Finder >> Browse >> Hardware Input and Output >> DAQmx >> Synchronization >> Multi-Function >> “Multi-Function-Synch AE-Read Dig Chan.vi”

You could also modify the example to include Clocked DIO (supported by the 6251) to eliminate any cases where you might lose data.

Furthermore, with the 2D data array, I would recommend the “build array” function node and wire it directly to an XY graph. I’m not sure of what you application is but I’m sure there are many possibilities… that is if you are using LabVIEW. 😉

I hope this helps and feel free to respond if you have any further questions!

Thanks,

[Spadacar]

Jordan,
thanks for your reply.
I'm using LabVIEW 8.20.
Does your example work also if I use external clock and trigger start for AI?
My external clock is continuous.
I'd like to implement also trigger start for DI but it doesn't suport it.
regards
Carlo

[JordanRandall]

Hey Carlo,

The example demonstrates how to acquire analog and digital data at the same time, synchronized with one another on your device. The example is definitely a great starting point for a continuous external clock because the DAQmx timing VI is already set to Sample Clock and Continuous.

Once you have the VI acquiring continuously on your 6251 you can start adding your triggering.

Let me know how it goes!