The Methods

This page will go over the procedure of the experiment. This page also functions as a user's manual for running an experiment.

Step 1: Initialization

From the MATLAB terminal, the user calls the script. For this particular experiment, the script was called "Therm3d_sdk_cdh.m".

For the most part, this first step involves initializing and calibrating the various devices associated with the script. At most parts of this first step, the script will prompt the user to press any key when the initializing action is complete.

Windaq and the DATAQ: Part 1

The script will start up the Windaq software.

The script will ask the user to press any key when Windaq is running. When a key is pressed, the script will proceed.

Header File

Associated with each experiment is a header file (.HDR), which contains all the experiment's parameter information. Examples of parameters contained in the header file include

• Experiment name
• Temperature Set (the temperature that will be observed over the course of the experiment)
• Numbers of Channels to be used for temperature measurement

The script parses the header file and sets script variables to be equal to header file parameters.

ThermoHaake

The ThermoHaake pump speed is set to an appropriate value (for now it is a hard-coded value of 50). Then the water is circulated with no heating. This is accomplished by setting the target temperature (or temperature to be heated to) to 10 degrees Celsius and pumping the water. The water is pumped to ensure that the there is little to no temperature gradient in the water for the rest of the initialization process.

Windaq and DATAQ: Part 2

Callibrating the Thermocouples

The script will ask the user to place the thermocouples under the ThermoHaake thermistor and verify that they are there with a key press. For each thermocouple, a temperature measurement will be made. Then the thermocouple measurement system will be modified to match the ThermoHaake thermistor. This is done by observing the equation

<math>y=mx+b</math>

where y is the temperature output of the system (or the measurement), x is the temperature input (or the actual measurement of the thermocouple), m is the slope which is a parameter of the thermocouple, and b is the offset which is determined by this part of the experiment.

The slopes are predetermined and saved as mat-file (in this case as TCSlopes.mat). The script loads the mat-file and passes the values into further calculations.

The offset is determined by the shifting of the previous equation to be

<math>b=y-mx</math>.

We know x and m. If use the ThermoHaake thermistor measurement, which we treat as the actual temperature of the water, as our y value, then we can solve for b.