Temperature

=Temperature=

Background
The temperature sensors used for DREAMS are the TMP36 from Analog Devices and the Platinum RTD from Honeywell. The TMP36 is a thermocouple, and the Platinum RTD is a resistance thermometer. Thermocouples consist of two dissimilar conductors in contact that produce a voltage when heated. The voltage is dependent on the difference of temperature between the junction and other parts of the circuit. Resistance thermometers record temperature using the temperature dependency of electrical resistance. The Platinum RTD is a positive temperature coefficient thermosistor, meaning that its resistance increases with rising temperature.

Equation
TMP36 Output Voltage vs. Temperature Graph The line labeled b is the output voltage vs. temperature function associated with the TMP36 sensor. The function relating temperature and output voltage is T = (V-3)/10.

Platinum RTD Resistance vs. Temperature Graph

Platinum RTD Behavior Function This screenshot from the Platinum RTD spec sheet gives a function for the resistance given temperature. The equation used for our sensor is

[[file:Data TMP36.csv]]
We conducted testing with the temperature sensors to see how they recorded data, and what that data actually meant. Therefore, when we conducted the culminating experiment with the main vessel, we could use our comprehension of the temperature sensors to understand abnormalities in other sensor’s data. The testing stimulus that we chose to use for our experimentation was ice. We placed ice on each of the working sensors, and combined the data into one graphical representation shown above. We expected different drops in the data points to correlate with the time we placed the ice on each sensor. Several examples of how quick the sensors responded to the stimuli can be seen in sensors 0, 1, 7, and 15. These sensors responded the most to the sudden change in temperature as you can see the sudden drop in data points over time. While the sensors did respond quite well to the extreme change in temperature, the original data was not recorded in regular degrees Celsius. Instead, as noted by the spec sheet, our data was a multiple of 10 higher than the actual reading in degrees Celsius. So by dividing the values in our data by 10 we were able to convert them.
 * Analysis**