Mixed Signal Waveform Graph

[Vills]

Hello,

I want to plot the temperature variation indicated by two thermocouples (which are connected to NI DAQmx Analog Input Module) with repsect to time (two curves for thermocouple 1 and 2) on a single waveform graph. The two thermocouples are connected in two separate channels in the module. The waveform graph needs to be displayed in the front pannel as well as exported to a spreadsheet.

I have bundled the input of time and the temperature readings of both thermocouples separately. and then tried to build a cluster array. However I am getting an error message. Please review the attached VI and helpme in getting the expected output.

Thank you,

Vilas V Jangale

[Parny]

Check whether it heps...

[Vills]

Hello Parny,

Thank you very much for your reply. When I tried to run the program, after a few seconds, the following warning/error messages were displayed. This was because the execution was stopped at the second tunnel of the while loop. (the tunnel through which the waveform grpah is sent to spreadsheet file.) Please find the attaches screenshot of the error message.

1^st dialogue box:

LabVIEW: Memory is full.

LV was stopped at loop tunnel “ ” at a call to “modified_2 Thermocouple Waveform Graph.vi”

2^nd dialogue box:

Not enough memory to complete this operation.

[Vills]

Does this error occur when we open a number of VIs at the same time?

[Parny]

Sorry, I was not focussing other than your conenctions in your example. Your while-loop is forced to run at cpu speed and overtaking the resources, which was the case before.

Add few miliseconds delay in the loop to avoid stress on the memory resources. Check the enclosed.

-Does this error occur when we open a number of VIs at the same time?

I dont think so.

[Vills]

Thank you very much Parny. Please find the attached output excel sheet. The sheet contains just the values of time and some temperature values, but not the graph of temperature vs time.

Thank you,

Vilas

[RavensFan]

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Vills wrote:

Thank you very much Parny. Please find the attached output excel sheet. The sheet contains just the values of time and some temperature values, but not the graph of temperature vs time.

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Of course not.

What you have is not truly an Excel file.  It is just a text file that was given an .xls extension.

The Export Waveforms to Spreadsheet File doesn't create an Excel spreadsheet file, just a text file.  There is no way to create a graph within a text file.  It has to be done in Excel itself.

You can either create the graph manually in Excel, run a Macro in Excel to create it for you, or use ActiveX programming in LabVIEW to direct Excel to open the data file, import it, and create the graph.  That option is not exactly easy, but can be done.  You should search the forums for Excel and ActiveX or look at the Excel message board to learn how to do that.

[Vills]

Thank you very much Ravens and Parny. This really helped me a lot.

[Vills]

But, if we look at the data in the output sheet, we can easily notice that the values of temperature are continuously increasing, but while executing the program, I made random changes in the reading of the thermocouple (not continuously increasing, but sometimes increasing and sometimes I reduced the thermometer reading.) Also there is only ONE Y column. As far as I understood, there should be 2 Y columns for TWO thermocouples.

[RavensFan]

First, please don't mark your message #3 as the solution to your problem.  You didn't solve your own problem.  The solution was one of Parny's messages.  You can use the Options menu in the upper right corner of your message to unmark it as the solution.

I know why you only have 1 data column.  You are using the build waveform function, but only once.  You have 4 Y inputs, the Y array input keeps overwriting the input above it.  You need to build 3 waveforms and build them into an array.

Message Edited by Ravens Fan on 03-03-2009 09:53 PM