using DAQ-6009 for simultaneous measurement from a single program

[psdy]

Hi friends,

                  I am having a DAQ-6009 which I want to use for measuring load values from two load cells together by connecting them to two separate analogoue input channels. I have generated a labview code which can read and show input from any channel.

I tried calling the vi twice in the "main vi" inputting separate analogue input channels in their controls which obviously did not work since DAQ 6009 cannot do simultaneous acquisition. Can anyone suggest a way of accomplishing the same without using separate DAQ cards. Slight time difference of the order of milliseconds in between two measurements will be acceptable for me.

Thank you,

Partha

[Dennis_Knutson]

Don't use two different instances of the same subVI. Just use a single subVI and have multiple channels in the list. For example, to acquire channels 0 and 1, your phsical channel list will be Dev1/ai0:1. Click on the physical channel control, select Browse, and use you mouse and either the shift or Ctrl key to see how easy it is to select multiple channels.

[psd]

 Hi Dennis,

                   I got this one;  but for further signal processing or  writing the subsequent processed data in a binary format what should be my approach?

Thank you,

Partha

[Dennis_Knutson]

Without further information, all I can say is you have to use the signal processing functions of your choice on the signal processing palette and one of the functions on the file i/o palette. If you have a specific question about one of the functions, what is it?

[psd]

Dennis,

             I want to get a time averaged value of the signals ; which I want to differentiate to get the rate of change of load. This data, I will be using to control my stepper motor velocity

 so that the rate of load change is constant.

So basically, I need to be able to separate the two streams of data , analyze them separately and then use it to control my stepper motor.

Thank you,

Partha

[Dennis_Knutson]

If you are asking how to separate the two signals, then you can just use the index array function. You configure the DAQmx Read to return either a 1D waveform array or a 2D DBL array. Some of the signal processing functions require a waveform input because a waveform data type contains timing information. You could also use a Split Signal function.