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Labview and internal temperature reference

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Labview and internal temperature reference

Postby guest » Thu Oct 16, 2003 10:10 pm

I would like to access the internal cold junction temperature reference value of the TC08 using Labview. Essentially this is a free channel for the room temperature. So it's not a TC08 but a TC08 plus room temperature! cool ehh. No pun intended

Although the prototypes in the tc08_labview DLL function look the same as the tc08_get_cold_junction function, after inspection and testing it becomes clearer that there are some modifications to support Labview.

If one attempts to use the Labview RS232 modules to communicate directly bypassing the custom DLL then the RTS /DTR lines appear to be in the correct state. In writing my own RS232 handler code to force the RTS and DTR into the correct states to power the TC08 directly, there appears to be some other issue in communicating and things do not appear to be as described in the on-line help. I could then bypass the DLL completely.

I am not confident as the custom Labview RS232 driver did not function. Despite considerable signal analysis hardware to ensure that the correct data was being received by the TC08. Alternatively I could permenantly supply the unit with power but all this is messy, especially as it could be available for free through the COM port. Again the problems with attempting to get a custom driver running so as not to rely on the DLL concern me.

Is it possible to get an update DLL driver that will allow this or should I dig in and write my own stuff.
guest
 

Postby markspencer » Fri Oct 17, 2003 7:43 am

Hi,

I have tried the latest driver with labview, but the only function that operates correctly, is the function specifically designed specifically for the TC-08.

The instructions for writing your own driver are correct in the manual for the C programming language. Unfortunately, I do not have the experience of Labview to offer a solution on how to write your own program.

What I can tell you is, in C the com port is connected to with the DTR and RTS both disabled and then the RTS and DTR are enabled (high) and disabled (low) respectively, to give the unit power and to initialise the unit. Once this has been done, the units version has to be asked for, before any thing else. If the version is not asked for you will not get any results.

If the unit is not being powered, check it functions correctly with Picolog.

Best regards,
Regards,

Mark Spencer
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Postby guest » Fri Oct 17, 2003 9:24 am

Thanks for the quick response.
To clarify a little: -

a) I wanted to let Labview users know that accessing other than through the Labview hook in the TC08 DLL would be 'fun / trouble' :) .

b) That attempting to access the TC08 using Labview's serial drivers thus bypassing the TC08 DLL is not straight forward. I can confirm that the RTS/DTR were in the correct state measued using a Fluke Oscilloscope. I can confirm that my code sent the correct bytes to the TC08 and arrived on the correct pin of the serial port at the TC08. (This is just to let you know its fun out here - not to get you to fix some end users bad coding).

Questions
-----------
1) Did you have an alternate technique for accessing the internal temperature reference using Labview.

2) Is there a chance that rev 5.08 TC08 DLL could be updated to allow labview to access more functionality from the TC08. i.e. The internal temperature reference ?

3) What time scale are we looking at for any update of the driver ?

Cheers
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Postby markspencer » Tue Oct 21, 2003 7:40 am

Hi,

Unfortunately, it does seem that labview can only be used with the the labview function provided.

I will make a recommendation that the driver be upgraded but cannot provide a time scale for this. I have also tested the later drivers with labview, these perform in the same manner as the older drivers and only allow access through the one function.

Best regards,
Regards,

Mark Spencer
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Postby guest » Tue Oct 21, 2003 4:34 pm

Thanks for confirming the issue identified.

I had hoped for a timescale.. :(

I have some ideas for an interim solution.
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labview driver success

Postby EricI » Tue Nov 04, 2003 4:24 pm

After some trial and error, I have had some success directly communicating with the TC08 over a serial port from labview. I could not read any temperatures until I read the version first then a temperature or the cold junction ref or thermistor.

If this helps, I can send the VI I write.

email me at
elynessmhs@yahoo.com
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Labview TC08 Internal temperature reference and simulator

Postby Guest » Tue Feb 17, 2004 7:43 pm

Well the result of all our hard work is now available....

There are Labview only drivers and example code available at......

http://members.lycos.co.uk/sgctek/

These mean that you don't need to use the DLL and can benefit from being able to read the internal temperature reference for room temperature from Labview.
Guest
 

TC08 Temperature Simulator Calibrator or Calibration

Postby Guest » Tue Feb 17, 2004 8:09 pm

Ooops forgot to mention I wrote a temperature simulator for the TC08 so that you can test you own software or system using either: -

1) 2 com ports on one P.C.
2) 2 P.Cs

The software is designed to run on a low performance machine such as an old portable or other machine.

See the link below: -

http://members.lycos.co.uk/sgctek/
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