How to SET DAQ digital output in mid DAQ Acquisition in Labview

[R_Green]

Please Help...

I must acquire a signal step response from a system.

I must guarantee to capture all of the response, so I want to start acquiring a sample, and then in mid sample acquisition SET a digital output to 1.

How could I do this?

I have only one DAQ acquisition board model PCI-622 with a CB 68LP adapter.

Please help...

Thx in Advance

[Jean-Philippe_C]

Hi,

In order to help you, I need some more explanations.

First what is your board exactly? PCI 6220, 6221? Because I think 622 is a mistake, isn’t it?

Then, if I rephrase your problem: you want to acquire an analog signal (a step response). And, in the middle of the acquisition you want to put a 1 on a digital output.

So my questions:

1)      How much time will last the acquisition (actually the response of your system) approximately?

2)      How do you define “the middle of the acquisition”?

I am waiting for your answer.

Regards.

PS : We can also talk in french if you want.

[R_Green]

Hi,

many thanks for your prompt reply...

Yes! Sorry for the mistake... Its a 6221 model...

1) The settling time for my signal will be around 100us;

2)Ok... I will define the problem better better...

-Lets say the whole process will take around 120us;

-At T=0us I want to start acquiring with maximum samplerate; 250Ks/sec==>1 sample every 4us;

-At T=10us I want to send the output signal to one the excite the system;

-The output must stay at one;

-At T=120us the data acquisition will stop;

-After (time is not important) the output can be but back to 0.

Hope this explains it better. Thanx for the help...

I speak a bit of french but sadly a bit rusty 🙂

Ricardo Greenfield

[GovBob]

Ricardo,

 It sounds like you could use pre and post triggering samples for this application. Are you using a digital trigger to stimulate your system? Maybe this tutorial could help.