Test and Measurement Forum

Sudden drop-off of temperature readings.

Post any questions you may have about our current range of USB data loggers

Sudden drop-off of temperature readings.

Postby Smynch » Thu May 08, 2008 2:34 pm

I use a grounded USB TC-08. I am using K-type thermocouples to monitor the temperatures of the surface of a bulb which outputs UV light. The bulbs are very similar to normal strip fluorescent bulbs, but the surface can get to 950 degrees C.

However during testing I can be seeing normal temperatures from 800 - 950 C when the readings will suddenly drop off to around half, where nothing in the system I am testing has changed. Strangely I can turn the bulb off and the normal temperature reading can be obtained again, before the bulb starts to cool down. This suggests that the bulb is causing some interference in the thermocouples which translates to poor results. Could this be the case? Or is there another possibility?
Posts: 1
Joined: Thu May 08, 2008 2:24 pm

Postby picojohn » Fri May 09, 2008 2:11 pm

Hello Smynch,

From the account that you have given, the phenomenon be may be characteristic of noise type behaviour, perhaps as a result of a peak in thermal noise at the higher temperature.

If not already doing so, you may wish to try using a screened thermocouple, with the screen grounded. Try grounding the 'sending end' and 'receiving end' alternately.

Zen Master
Zen Master
Posts: 382
Joined: Mon Jun 11, 2007 1:10 pm

Return to USB PC Data Loggers

Who is online

Users browsing this forum: No registered users and 0 guests