LabVIEW

A few comments to get you started.

1.  You actually aren't writing to an Excel file.  You have given the file names an .xls extension, but they are actually text files with the data saved in a format that can be imported by Excel.

2.  In order to save the data while the program is running, you will have to put your Write to Spreadsheet File VI's inside the loop and append data.

3.  The reason your VI gets stuck inside the case structure is that you have a while loop inside the Write Trace to File VI.  Since it is called as a subVI, its front panel won't open.  And the only way to stop that VI is to hit the stop button on its front panel.  A catch-22.

4.  That subVI really doesn't make sense.  It has a loop where every 6 seconds, it opens a file, writes data to it (overwriting the data already there) then closes it.  And it is always writing the same data because the data it uses comes from outside the loop.  Is this a VI that you took and modified yourself?  Don't.

5.   You want to completely redo the architecture on this program.

A.  Use a state machine.  Since you have a series of steps:  Heat up, stabilize, wait, go to another temperature and repeat.  Each of those should be a step within a state machine.

B.  Use a producer consumer architecture to communicate data.  One loop will be the state machine.  Another loop, (a producer) will acquire data.  Another loop (consumer) will graph the data.  Another loop (consumer) will log the data to a file.  Another loop (probably consumer), will be your temperature control loop.  Using Queues and Notifiers will allow you to pass data from the producer to the consumer loops and also notify your state machine when to change states.

  Thanks for the response but I could not even get started. The problem is so involved.

At first, I need to take 6 sets of data as reference measurement and then the program needs to turn the thermostat on and take another 6 sets of data and so on. The thing is all these are to be automatically done.

 How can I make the program Write Trace to File.VI to trace the OSA data automatically-without asking for user feedback- .

It asks the user whether or not to trace data when a certain condition is met.

  Also, can I use a template to implement the state machine?

What user feedback are you talking about?

For the state machine template, go to File /  New....  then see attached.

The four VIs inside of the library "86140B Trace_Screen Capture(2).llb." work synchronously and they can not be seperated. In my previous code, when the temperature stabilized it asked me whether or not to trace data as seen in the picture. That's the input that I am talking about.

 Besides, can you suggest me another way of checking temperature stability? Like comparison of the current temperature value with the previous ones   (Right now I need to define temperature values for checking that and I need to do that without any need of user input)

Where did you get that .llb file from?

It is very poorly written.  I had already mentioned the issue with the while loop inside the Write Trace to File.VI.  The issue with it asking for a file name seems to come from the VI called Image Xfer.VI.

Inside is a Write to Binary File with no wire going into the file path.  So it will ask you for a filename each time that VI is called.  And whoever wrote that VI didn't even bother putting a File Path control in it and wiring it to the connector panel so you could programmatically define the file to write to.

Go find out who created that .llb and beat them over the head with it.  Then figure out how it works and rewrite it so it works properly.  The VI's aren't that complicated.

Ultimately, you will have to define for yourself what temperature stabilization means.  Does it mean that the you have two consecutive identical temperature measurements?  If it was me, I would say the average of the last 10 readings in the past minute and the average of the last 10 readings before that have a difference of less than let's say 2 degrees.  I would write a subVI that keeps track of the last 20 readings, does the math on them, and outputs a True or a False based on that criteria.  I would probably make it an action engine  (see Action Engine Nugget) so that I could have some initialization and reset cases to clear and reset the data.

---

aeastet wrote:
Hey Ravens Fan you should tell us what you really think about that VI.

---

 Thank you all for your replies

I modified the code as attached. It is not even half done. I  need to make a whole lot of improvements but can you please comment on the code? Am I in the correct direction?

    The code will acquire the thermocouple reading as long as it runs. Also it will take 6 sets of data when it is first run. (by the way I need to make the filenames that the  wavelength power data is saved different everytime the code is executed.)

 Also, the the thermostat will be turned on depending on the temperature stability condition. (depending on thermocouple reading) How can I pass elapsed time and thermocouple reading data between the loops?