DAQmx AI data acquisition error

[Vij@y]

Hello Everyone,

I'm using NI DAQ 6353 for a Analog Input data acquisition of Sin and Cos voltage signals. 

When I set the sampling rate to 1000000, I get an error from DAQmx as stated on below:

Possible reason(s):

Some or all of the samples requested have not yet been acquired.
To wait for the samples to become available use a longer read timeout or read later in your program. To make the samples available sooner, increase the sample rate. If your task uses a start trigger, make sure that your start trigger is configured correctly. It is also possible that you configured the task for external timing, and no clock was supplied. If this is the case, supply an external clock.

Property: RelativeTo
Corresponding Value: Current Read Position
Property: Offset
Corresponding Value: 0

Task Name: _unnamedTask<15>

Also please find the configuration parameters for DAQ on below:

Requesting support to resolve this Issue and acquire the samples as per sampling rate specified.

Thanks,

Vijay

[JÞB]

It is next to impossible to evaluate your code from a picture of the Front Panel. 

Do you have anything connected to PFI7?  Is it a 1 MHz clock?  How long is the timeout?  How many samples are actually read?

[santo_13]

What are the voltage levels of the clock signal applied at PFI7?

[Vij@y]

Hello Santhosh,

0 to 5v is the voltage levels of clock signals at PFI7.

Thanks,

Vijay

[Vij@y]

Hello Jay,

It's just a NI example I had taken to see the AI acquired data.

Do you have anything connected to PFI7?

Ans: voltage signal ranging from 0 to 5v.

Is it a 1 MHz clock?

3.5MHz clock.

How long is the timeout?

10 secs.

How many samples are actually read?

Sampling Rate - 960000S/s.

Samples used - 960000S/s.

Thanks,

Vijay

[Kevin_Price]

Did you modify the block diagram of the example?  Several things don't add up here. 

1. You talk about measuring Sin and Cos signals but are configured for only a single channel of acquisition

2. Your 6353 device is only rated for 1 MHz max sample rate for multi-channel acquisition (1.25 MHz for single-channel), but you're trying to drive sampling with a 3.5 MHz clock.

3. When you configure for an external clock (using PFI7), DAQmx will simply *believe* you about the sample rate you claim and should return the exact same value as the actual sample rate.

    So you physically wired up a 3.5 MHz clock, told DAQmx you were going to sample at 1 MHz, and then DAQmx came back and said your "actual sample rate" was 960 kHz?  I'm not inclined to believe that.

The error you get suggests that you aren't receiving a valid clock signal at PFI7.   Use the counter tab of a MAX test panel to do edge counting of PFI7 to see whether it registers ~3.5 million counts per second.

-Kevin P