Acquiring Analog Input from Multiple Channels in Labview

[Engr_tech]

Hello,

i am working on a VI where i need to acquire signals from multiple channels in Labview using NI-9129.Initially i want to acquire contineous input signals (voltage and current) and display it on the graph.

Having looked at forum and Labview examples i tried to make an initail VI but i am not sure if the setup i made needs any modification to serve my purpose.I am fairly new to Labview software.

All i want is

1.To acquire conteneously current and voltage 

2.Display current and voltage individually on the graph.

3.Perform some basic calculations like MAXIMUM,MINIMUM and AVERAGE values of voltage and current.

4.Log the data into  excel file

I have attached the VI i made so far.i need abit of advice if i am moving in the right direction or not.

Thank You for having a look at my question.

[Dennis_Knutson]

Can you attach an image of the block diagram. I'm posting from my phone and I can't look at the VI.

[Engr_tech]

Thanks for your reply.Here is the Snap of the VI

[Dennis_Knutson]

You are passing the very last acquisition out of the loop. If you want continuous measurements of min, max, etc., you need to do the calculations inside the loop. Better would be to implement a producer/consumer architecture since you can run into buffer problems trying to do continuous acquisition and processing and saving in the same loop. I would recommend tdms for the file saving.

[crossrulz]

You probably want your calculated values to be continuously updated.  Therefore, they should be INSIDE of your loop.  Otherwise, it looks good to me.  Make sure your logging mode is set to Read and Log.

[Engr_tech]

Allright thank You for the prompt replies

I definitely require  to Get values for Max/Min etc continesouly.As per your suggestions,, i will put the Max,Min and mean inside the loop.

i think i already have the tdms for  data logging.as far as the tdms data logging is concerned,when i enable the logging mode to "read and log" the data logged inside the excel sheet would be seperate for current and voltage.?

Is it practically possible to acquire data from 4 different channels and plot them.if yes,then am i right to assume that all i need is to modify the current VI for four channels having all of them in parallel.

Thank You for your suggestions

[crossrulz]

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@Engr_tech wrote:

i think i already have the tdms for  data logging.as far as the tdms data logging is concerned,when i enable the logging mode to "read and log" the data logged inside the excel sheet would be seperate for current and voltage.?

Is it practically possible to acquire data from 4 different channels and plot them.if yes,then am i right to assume that all i need is to modify the current VI for four channels having all of them in parallel.

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Yes, you are logging directly to a TDMS file.  This is definately the best route for data logging from a DAQ.  The currents and voltages will show up as different channels in the same group.

To add more channels, just add them to your DAQmx task.  The logging will handle it with no issue.  Your calculations will also a little work to add the extra channels.  Same for the graphs, since you are using seperate charts.