It should be either decrease or increase for nth time during heat supply. Is there any possibility of irregular temperature sequences as shown in figure. In that picture the highest temperature lies around 168 °C, but that values keep decreasing and increasing. What causes it ?
The method of heat supply is two- probe electrode method. Probe material is copper. The values were recorded using a thermal camera. Time and current value is constant.
Hi Nagamani Yadavalli,
If there is gas around the sample, then thermal convection of the gas is the cause of the random walk of temperature.
Also, how many significant digits is the accuracy of your power supply? If the current has 3/4 significant digits, then the 4th/5th digits are unstable. It will affect the 4th/5th digit of temperature. Please also check the accuracy of the thermal camera in the instruction manual.
By the way, is it really necessary to control the temperature by 0.01 degree? For example, if there is a phase transition of matter at 168.05 degrees and the physical properties are expected to change significantly between 168.01 and 168.08 degrees, I think in such a case, your supervisor should tell you to do the experiment with a senior researcher.
Hello Mr. Kengo Shibuya, Thanks for answering.
I will make sure about the power supply and thermal camera accuracy once again.
Here we are trying not to control the temperature for developed instrument. We need to characterize the instrument first. Because of that, we need to find the cause behind that behavior. Then we can able to analyse more necessary parameter.
Nagamani Yadavalli
Looks like a normal feedback loop to me where the resolution of the measurement is much greater than the set and actual temperatures.
Hello Mr. Alan F Rawle, thanks for answering. Could you please elaborate your opinion more if possible. Thank you.
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