Help needed with multiple current and frequence measurement

[Jaco]

Hi guys

I am starting to come right with labview, but still a few problems. I need to take multiple current (x12) and frequence (x2) measurements. I've gotten readings (both current and freq) but only one at a time. What do I need to do to be able to take all 14 measurement at the same time. 

Measurements should be taken continously at about 1 per second and all measurements are ref to ground. (not differensial)

If someone could point me in the right direction or write me a VI explaning what I need to do.

Thx

[Rupali]

Hi.. 🙂

       Even I'm a new comer in Labview, recently I worked on a VI where I'm measuring 8 voltage inputs but those are differential... I used DAQ Assistant, in that I added all the channels from where I'm getting my inputs & set  them differential through "Terminal Configuration block".. Then I splitted them using "Split Signal" Function.

        I think you can do the same.. Add all channels in DAQ Assistant, then set the reference & after that you can split them, then perform measurements. I hope you can get atleast an idea from this.. Best luck 🙂

[Cory_K]

We're gonna need to know a few things first.

What hardware are you using to measure current and frequency?

How is this hardware connected to the computer (ie serial, usb, gpib etc)?

You are probably going to want to use the DAQ Assistant since you are relatively new to LabVIEW. This will help with the communication with the hardware.
After that, you can either display the data or write it to a file. We can help with that once you get there. 

[Wallace_F]

Hello Jaco,

I agree with Cory K when he says that we need to know what hardware you are using and how the hardware is connected to your computer.  I would add that we would also like to know what version of LabVIEW you are using as well.  That being as it is, I will assume that you are using an M-series DAQ board in order to outline the procedure for setting up your measurement tasks in LabVIEW.  The procedures below apply.

Measuring Current:

1.  Open a blank VI in LabVIEW and select Window >> Show block diagram from the menu options.

2.  Right click on any space in the block diagram to show the functions palette.

3.  On the functions palette, navigate to Measurement I/O >> DAQmx, left-click on the DAQ Assistant and drag and drop it onto your block diagram.

4.  In the DAQ Assistant configuration window, select Acquire Signals >> Analog Input >> Current.

5.  Within the Physical tab, click the + next to your DAQ device, click on the physical channel that your current source is connected to on your DAQ board, and click on Finish.

     a.  To select more than one channel, click on the first channel, press the shift key and click on the last channel you want to include in your current measurement task.

6.  Enter the following parameters in the Settings tab: Signal Input Range, Scaled Units, Shunt Resistor(Internal or External), Resistor Value, Terminal Configuration (Differential),

     Custom Scaling.

     Note:  You typically must use differential terminal configuration to measure current.

7.  Switch to the Triggering tab and select trigger type for Start Trigger and Reference Trigger if applicable.

8.  Switch to the Advanced Timing tab and select Sample Clock Type, Clock Source, Active Edge, and Timeout(s) as required.

9.  Hit the OK button.

10. Right click on the Data output terminal on the right side of the DAQ Assistant icon on your block diagram and select Create >> Graph Indicator or Numeric Indicator as  

      required.

Regards,

Wallace F.

[Wallace_F]

Measuring Frequency:

1.  Repeat steps 1 - 3 from procedure for measuring current.

2.  In the DAQ Assistant configuration window, select Acquire Signals >> Counter Input >> Frequency.

3.  In the Physical tab, click the + next to your DAQ board and select the counter input to which your frequency source is connected and click Finish.

4.  In the Settings tab of your Frequency Setup, select values for the following parameters: Signal Input Range, Scaled Units, Starting Edge, and Measurement Method, and

     Custom Scaling, Acquisition Mode, and Samples to Read and click the OK button.

5.  Repeat steps 1 - 4 for any additional frequency measurement tasks or channels that you require.

6.  On the block diagram, right click on the Data output terminal of the DAQ Assistant icon for your counter input tasks and select Create >> Numeric Indicator.

I believe that the information in this post and my previous post should help you get started with creating your current and frequency measurement tasks in LabVIEW.  If you have questions, please post them.

Regards,

Wallace F.