Linear Temperature Ramp Program

[realperson1223]

I am taking as input the current temperature of the system and user input of a desired start temperature, end temperature, and ramp rate. If the input temp is below the desired start temperature I need it to go straight to the start temperature. Otherwise I need it to linearly ramp to the end temperature. I have been able to get the ramping kinda working using the ramp subvi but there are several issues with the setup currently. When ramping it will loop infinitly between the start temperature and the end temperature and I am unsure how to get it to stop after one loop. The other main issue is the graphs get paused and don't update while the ramping is occurring and this causes data to not be recorded as well. Attached is the labview program thus far. Thank you for any help.

[altenbach]

Your VI has disconnected code fragments all over the diagram and start running as soon as the user presses the run button, requiring all control settings to be made in edit mode. Not user friendly!

I would recommend to rearchitect this into a clean state machine.

No you don't even need the inner FOR loop. You definitely don't need a formula node to calculate a high order polynomial. There is a simple tool that accepts x and an array of polynomial coefficients. That's all you need!

Sorry, I don't have drivers installed, so I cannot look at your assistant configuration.

[altenbach]

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@altenbach wrote:

You definitely don't need a formula node to calculate a high order polynomial.

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Hmmm....

[RTSLVU]

I do not see any type of I/O. Is this theoretical practice or a homework assignment? 

Every thermal chamber I have used had a built in controller. So programming a ramp is as simple as sending the controller start temperature, end temperature, and ramp rate in degrees per minute.

[altenbach]

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@RTSLVU wrote:

I do not see any type of I/O. Is this theoretical practice or a homework assignment? 

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There is a DAQ assistant read in the outer loop and a DAQ assistant write in the inner loop.

[GerdW]

Hmmm, too…

Do you really need a 10th order polynomial for conversion from voltage to temperature value?

[altenbach]

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@GerdW wrote:

Hmmm, too…

Do you really need a 10th order polynomial for conversion from voltage to temperature value?

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I was really wondering about that too and assumed that might have been blindly taken from a calibration sheet included with the sensor. 😄

Assuming +/- 10V, it is good from absolute zero (actually -3 TeraDegrees) to +8 TeraDegrees!) 😮

[realperson1223]

Thank you I have implemented this change. I am new to labview and saw a chance to type something rather than implement it through block code and took it as I normally to text based programming. Although I am quickly learning this is not how you should go about coding in labview.

[realperson1223]

I am an undergrad student working in a professors lab. He basically handed me a program three other students have been working on in the past and told me to learn labview and make it linearly ramp.

[realperson1223]

I have been trying to figure out how to increment through an array without using the inner for loop. I am currently reading about state machines in labview as per your recommendation. How would one go about doing this?