Help with data aquisition display

[ericm86]

Hi all,

Let me begin by saying I am a complete newbie to LabView and besides some minor lab work in school many years a go I don't have much experience with the software at all.

My project is, we are trying to implement a remote monitoring system for our Solar Panels.

I have 3 sources stepped down through CTs to +/- 10V going into my DAQ card:

PV power from solar inverter

Power drawn from local Utility

and Total power going into the plant.

My next step is to graphically display these values, in realtime with 3 different bar plots on the same graph.

Currently I have been playing with the niDAQ assist tool to get the values into labview.

Would anyone have any tips or point me in the direction of some helpful tutorials on how to take my 3 voltage readings and transfer them into a 3 source bar plot, ultimately I would like these three values to be displayed continueously on a screen in our office.

Thanks, any advice is much appriciated!

[Jacobson-ni]

Eric,

If you are set on using a bar plot, the following KB describes how to change the properties of a Waveform Graph to make it appear like a bar graph.

http://digital.ni.com/public.nsf/allkb/CC33DFA1BEBA84F0862562BA0001CBD3

If you want to display three voltages you can just build an array from your three voltages and feed them into your waveform graph indicator.  Unfortunately LabVIEW will not let you change the X-Axis to include non-numeric terms, meaning you will have to add labels to make it look the way you want.

You might also want to look at fill slides or progress bars if you are just trying to convey the current status.

[ericm86]

Thanks for the reply Matt,

I have reviewed the bar plot tutorial and it seems like that solution still leaves me with a waveform graph, I don't want my sources to vary in time in the X direction (just one bar going up and down).

The goal is to have the Yaxis be in kW and three bars moving up and down (not horizontally) along that Y axis for comparison.

It looks like three progress bars might be a good solution, I will look into this further.

Thanks again,

[Dennis_Knutson]

There is no reason that you can't use a graph. With each iteration, you plot the latest array of data and this does not change the x axis unless you program it to do so. Attach the code you've written. I suspect the problem lies in your use of the DAQ Assistant and the evil dynamic data type it creates.

[ericm86]

Hi All,

I have made some progress and got one of my DAQ inputs working well with a fill tank.

If I can get three fill tanks running simultaneously like I have in my attached project snapshop that would work well for my application.

However the approach I am using has a flaw that only one DAQmx read can be used at a time (something about resources being occupied).

I simply copied the same logic three times using a differnt I/O point each time, which seems to be the wrong approach.

I need to achieve each fill tank to display a seperate DAQ I/O with its own multiplier.

Thanks again for your helpful advice.

[Dennis_Knutson]

No. This resource reserved error has been discussed numerous, numerous times. You must use a single task with multiple channels. Specify all three channels with dev1\ai0:2 and use the NChan mode of the DAQmx Read.