Controlling Thermotron - Basic steps

[Timeslice]

Im an old VB/Visual studio coder making the leap to Labview 2009.

I need to control the temperature of a Thermotron 4800 environmental test chamber.  The communication is via RS232.

1.  I plan to use the VIs provided by Thermotron (of which there are MANY!).

2.  I want to simply initialize communication and then set a temperature (setpoint), wait for the chamber to reach that setpoint, and then proceed with the rest of my application.

3.  A simple VI with the minimum number of elements would really help me get a grip on this.

4.  Is there any relationship between VISA and the the VI's from Thermotron?

5.  I believe I need to install the "IVI Compliance Package" to support the Thermotron VIs.  I trust this is an additional download from NI?

I am hopeful that someone can share the fundamentals with respect to the above to get me started on the right track. 

Thanks for taking the time to read / respond to the above.

Scott

[smercurio_fc]

If you have an IVI driver then, yes, you will need to download the IVI Compliance Package. Since you've got an IVI driver, the VIs will be calling one or more DLLs. Thus, VISA would not be used in this case. As for what VIs you need to use, I haven't a clue since I don't have that driver. Downloading it from Thermotron requires registration, and I'm not about to do that just to download a driver to take a look at. Did the driver come with any example VIs? There should be some VIs for initializing the serial port, setting the temperature, running the Thermotron (i.e., starting the cooling/heating cycle) and reading the current temperature. Basically you would need to

1. Initialize

2. Send command to set the target temperature

3. In a loop read the temperature and stop it when you reach or (optionally), the user aborts.

[Timeslice]

Thanks for the assistance.  You've given me a start.

The TH4800 driver includes a huge set of VIs but no examples that I can find unfortunately. 

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smercurio_fc wrote:

... Did the driver come with any example VIs? There should be some VIs for initializing the serial port, setting the temperature, running the Thermotron (i.e., starting the cooling/heating cycle) and reading the current temperature. Basically you would need to ...

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[Vince Jelsema]

You have probably resolved your issues by now, but let me know if you still need example VIs - I'll see what I can find for you.

[Timeslice]

Thanks for the offer of help and others who also provided feedback.

After much experimentation I have succeeded in getting the thermotron talking / listening.  One of the confusing issues I ran into was getting the actual temp the TH4800 was at.  After some digging I discovered this was the "Get Current Process Variable" call or something similarly named.

Thanks again for the help.

[Broken_Arrow]

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Timeslice wrote:

Thanks for the offer of help and others who also provided feedback.

After much experimentation I have succeeded in getting the thermotron talking / listening.  One of the confusing issues I ran into was getting the actual temp the TH4800 was at.  After some digging I discovered this was the "Get Current Process Variable" call or something similarly named.

Thanks again for the help.

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You are likely to see "Process Variable" in similar equipment. The firmware is scalable for a wide variety of uses - temperature, humidity, PH, position, available light, etc etc.  So they don't have a command called "get temperature", although that would be nice!

[RTSLVU · Accepted solution]

I know it's not exactly the chamber you are using but here is some stuff I wrote for a Thermotron 8800.

The main difference is my 8800 is connected via Ethernet, but I think you will get the idea on how to make your own "get temperature" and "set temperature" vi's

I just made one basic control vi that uses a type def to select the command you want to send to the chamber.

[MF]

Any way you could post the code in LV 8.5 RTSLVU ? Thanks.

Michael

[RTSLVU]

I wish I could but when I try to save this for any previous version, Labview 2009 give me the error message: 

"Save for previous version failed due to unspecified error"

This "unspecified error" confuses and infureates me!

Maybe one of the regulars can load and save it for you?

[RavensFan]

Try this zip file.

For some reason, the original project had the project files *.lvproj, .aliases, and .lvlps included in them.  Why?  I think that confused the Save for Previous because it probably caused some type of recursion while doing the save.  Once I removed the project files out of the project, the save for previous then worked okay.

Message Edited by Ravens Fan on 02-10-2010 12:05 AM