Loopback test with simulated Hardware using NI MAX

[abhishek.d]

 I'm trying to generate continuous analog output and acquiring analog input , i dont have hardware(NI-PCIe6353) with me right now so i'm using simulated hardware.Now my question is can i do loopback test , to test that my generated signal and acquiring signal is same or not.

[Dennis_Knutson]

No. As explained in the help, the simulated input is only a sine wave.

[abhishek.d]

yes exactly that is what happening. actually i'm trying to generate a signal of 0 to 10 v and acquire that signal , so there is no way to test this without a harware right ? or is there anyway i can test whether the data i'm generating is reaching to the hardware or not 

[rolfk]

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@abhishek.d wrote:

yes exactly that is what happening. actually i'm trying to generate a signal of 0 to 10 v and acquire that signal , so there is no way to test this without a harware right ? or is there anyway i can test whether the data i'm generating is reaching to the hardware or not 

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What do you really try to test here? If you want to test if the data is reaching the hardware, no form of simulation will achieve this for you. You really need a physical hardware output to be able to generate a value that can control external hardware. If the aim is to be able to test your application without the need to have the hardware installed then you could always implement your own loopback where you store the generated data in a global variable (ideally you would use a Intelligent Global Variable or LabVIEW 2 style global for that) and read it back from it, possibly with some data processing to simulate external hardware influences or different updata and sampling rates that your application might use.

[abhishek.d]

Thanks a lot rolfk,

    Actually i wanted to test my application, i'm not aware the method you are telling to test this. can you tell me in brief so that i can execute that.

Right now i completed my coding part to generate the signal as well as acquiring the signal, now i just wanted to test them.

[rolfk]

This is a quick mockup of what I meant.

You use the "Data Read Analog Input.vi" where you have your "DAQmx Read.vi" and the "Data Write Analog Output.vi" where you have the the "DAQmx Write.vi". Use the "Simulation Global.vi" elsewhere in your program to enable and disable the loopback simulation.

[abhishek.d]

Hello Dennis Knuston,

      I have created an application which has both analog output(generation ) and Analog input (acquisiiton)

My Hardware is NI PCIe-6353 , SCB-68 connectory and then a bnc connector (BNC2120)

In order to test my input and output i just did loopback conection AO0 to AI0, basically my output signal is ramp , will my input signal can be only Sinewave.

i got output like this please have a look at the screenshot (Green=Analog out , Yellow =Analog In)

[Dennis_Knutson]

You have not provided any code or details on the generation and acquisition. Does the sample rate for the acquisition loop meet or exceed the Nyquist criteria?

[abhishek.d]

I'm assuming that i solved the issue what ever there in the screenshot in the last post but not sure.I'm attaching the screenshot of my entire VI and the marked portion of the screen is where i'm using read function(attached VI) , what i actually did is I just put one 2D transpose function  at the ouput of read VI and then it started showing same as generating signal(green color in last screenshot)but there is little bit fluctation in the read values  that means when my generated signal is constant at that instant acquired signal is fluctuating ( for example suppose my generated signal is constant at 300 amplitude when i'm reading that amplitude fluctuating between 299.00 and 300.00)

So i wanted to know what ever tranpose i did is the right or not..can you please suggest me something on this.