a problem with data acquisitioning in LV 7.1 (transition from Traditional NI-DAQ to NI-DAQmx)

[ero]

Hi to everyone,

I have a problem with data acquisitioning in LV 7.1.

I made a transition from Tradiotional NI-DAQ to NI-DAQmx in my LabVIEW application.

The problem I have is that when I acquire data in Traditional (without writing somewhere -

just reading) then there is no scan backlog data. But when I acquire data in application that

acquisition is based on DAQmx than a scan backlog indicator shows numbers from 20 to 50 for

about 6 min and then that number quite quickly increases until I get an error (unable to

acquire data. The data was overwritten).

Acquisition settings are the same in both cases. When I acquire with DAQmx I use a global

channels. Is a reason for that phenomenon in global channels data procesing? But it seems

strange why does it flows quite smoothly for about 6 min and then it stucks?


Best regards,

Ero

[parthabe]

Hi Ero,

Did you read these links - Getting Started with DAQmx and Transition From Traditional NI-DAQ to DAQmx?

[parthabe]

Also, pl do read from this post onwards.

[ero]

Hi parthabe,

Before I made a transition I read this link - Transition From Traditional NI-DAQ to DAQmx.

Now I am going to check out if in Getting Started with DAQmx is something I overlooked.

Thank you for your answer.

[parthabe]

Thank you for your response!

[Coq_Rouge]

If you have an old Daq unit it may not be compatible with DAQMX. Which DAQ unit do you have? I think NI have a list showing which DAQ driver you can use with your card

[ero]

Hello Coq rouge,

I have installed two DAQ cards (NI-PCI 6036E and NI-PCI 6071E) and the latest NI-DAQ 8.9 driver which supports both DAQ cards.

Thanks for you response.

[parthabe]

---

ero wrote:

I have installed two DAQ cards (NI-PCI 6036E and NI-PCI 6071E) and the latest NI-DAQ 8.9 driver which supports both DAQ cards.

---

I think you have misunderstood his question.

It is not the question of support for the cards, but whether or not the driver supports both Traditional DAQ devices & the latest DAQmx devices.

Hope this clears the air...

[ero]

Thanks parthabe!

Yes I misunderstood a question of Coq rouge.

And as you write down the driver supports both Traditional DAQ devices and DAQmx devices.

Thanks again.

[ero]

Hi to everyone again,

I've found out a new fact about the problem I have.

A page file usage is rising at data acquisitioning in

application based on NI-DAQmx (without writing somewhere -

just reading).
Why does it happen?

Is there any connection with a scan backlog data?
Because a scan backlog indicator shows the amount of data

that depends on a sampling rate.
If I acquire 19 channels with 10000 Hz then a scan backlog

indicator shows a number from 20 to 50.
And if I acquire with 50000 Hz then a scan backlog indicator

shows from 130 to 150.
But the strange thing here is that data flows normally for

about 6 min (a page file is increasing anyway and a scan

backlog indicator is stable - from 20 to 50 or 130 to 150)

in both cases and then after 6 min scan backlog number quite

quickly increases until I get an error.
An amount of a data accumulated in the page file is from 150

- 180 Mb from start to end of acquisition.

And when I acquire with an application that based on

Traditional DAQ then there is no scan backlog data and there

is no change in amount of a page file.