Inaccurate parameters

Technical Support and Questions

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jiandanyidian

Aug 2018

Hello, I have a problem with the parameter.I found that the parameter of “ambient temperature” is not very accurate when I use MultispeQ. Even when measured in a 4°C environment, it still shows about 27°C. Would be so kind to help me with this problem ?

  • created

    Aug 2018

  • last reply

    Sep 2018

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Luka Kramer

Aug 2018

Hello Sorry to hear you're having problems with measuring ambient temperature. Unfortunately, it takes a while for the instrument to adapt to a quick temperature change - sometimes up to several minutes. If the temperature reading stays the same, or if the results are still inaccurate after allowing adequate time to change, please email support@photosynq.org so we can further investigate.

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David M. Kramer

Sep 2018

Hi! It looks like you are using V1.0 devices, right?

As Luka pointed out, the THP (temperature/humidity/pressure sensors are inside the device and have to equilibrate with the ambient temperature.

Once last winter I did some measurements in cold weather and found that, unless I acclimated the device to the right temperature, not only would the readings be wrong, but the device itself could heat the leaves! Have a look at some of the data:

https://photosynq.org/projects/garlic-mustard-photosynthesis-in-winter/explore

IMPORTANT: set the Show Advanced Parameters option on to see these parameters.

As in the attached figure, ambient temperature against leaf temperature (measured using non-contact temperature sensor). Most of the points show a perfectly linear response except one outlier with showed much higher ambient than leaf because I had the device in my pocket ;-).

I had a look at some of your data and found a pretty consistent linear dependence of ambient and leaf, so it looks mostly pretty good. If you have more issues, why not try repeating measurements over time to determine how fast the temperature settled.

Also, the new V2.0 will have an optional pump that can exchange air over the leaf and THP sensors, so the equilibration time should be faster.

Cheers,

Dave