Thermocouple low temperatures


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I am using the UE9 (with CB37) at the moment to log 5 temperatures, using K-type thermocouples.

I need the highest possible resolution (1 degree Celsius), but also I need to measure temperatures below zero.

With the range set to a high resolution I can not measure below zero.

Is there an alternative way?

Is it perhaps possible to set the range to (109), bipolar -0.62V to 0.62V?

Kind Regards,

Marc Coenen

Inalfa Roof Systems

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Thanks for quick responce,

I have to measure till -40 degrees Celcius.

I set the range to 9 (-0.625V to 0.625V), it seems to work. However I did not calibrate it below zero till now.

Do you know if the measurements below zero are reliable?

Kind Regards,

Marc Coenen.

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The UE9 does have bipolar ranges with gain (LJ_rgBIP2P5V, LJ_rgBIP1P25V, LJ_rgBIPP625V), but they have not been tested enough to be specified or supported. They are calibrated at the factory, and the low-level functions can use them, but they do not work with the UD driver. The bipolar ranges with gain are likely a little noisier and slower than the normal specified ranges.

-40 degrees C is only -1.5 mV of output from a type K thermocouple. You can read that no problem with any of the unipolar ranges such as 0-0.625. The unipolar ranges go to about -12 mV, and the negative limit of a type K thermocouple is -270 degrees C where it outputs only -6.5 mV. Even if the bipolar LJ_rgBIPP625V range is supported, the unipolar LJ_rgUNIP625V range will handle the output of your thermocouple with resolution that is better by a factor of 2.

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