Getting Started: Run an Experiment
An experiment is run using the control page, which can be accessed through the navigation menu (under "Experiment control") or through a [direct link] (www.experimentwebsite.uwa.edu.au/control). After logging in, it should appear as below:
![Control page] (http://i.imgur.com/JMJ5V2Z.png)
Displayed at the top is a bar with the experiment state (red in the image as the server is not connected). This displays - surprise! - the current state of the experiment hardware. This can be either experiment started, experiment paused, no experiment running, emergency mode, connection failed, or unknown. These states should be relatively self-explanatory. Below this is a status box which will display any any error or warning messages that the software has produced; this is useful for following the current activity of the software or for diagnosing any possible errors. While it is important to keep note of any warnings that appear, some are just for information/debugging purposes and do not indicate a serious failure. The level of warnings which are printed on the GUI can be changed in the software.
Note: The experiment can be immediately stopped by using the "stop" button in the experiment state bar.
This section is for starting a new experiment. The experiment's name (try and make this descriptive) is entered in the text field, with the option to overwrite an existing experiment with the same name if this is desired. The experiment mode can then be set - a strain test will just strain the can to a certain level to test is deformation behaviour, while an explode test will pressurise the can to its failure point. Clicking on either of these buttons will start the experiment process.
Below the "start an experiment" box are the experimental controls. These appear as below:
- The Starting Pressure (kPa) input box allows you to set the starting pressure in kilopascals. This must be numeric and within an acceptable range; an error message will be displayed if the pressure is invalid. Bear in mind that the pressure range for the exploding can experiment is around 0-600kPa.
- The Pressure step size (kPa) input box allows you to set the step size by which pressure is increased. In the experiment, pressure works as a step function; it is set to a certain level, then increased in discrete steps. A step size of 10kPa (for example) will increase the pressure in 10kPa jumps.
- The Number of steps to make box allows you to set the number of pressure steps. Keep in mind that this essentially determines your final pressure, and that the experiment must fall within the system's pressure limits. For example, starting at 0kPa with 10 steps of 20kPa each will result in a final pressure of 200kPa. The experiment ends once the final step is reached and stabilised.
- The Wait time between steps (s) box allows you to set the time between pressure steps in seconds. The system will set the pressure regulator to the desired pressure, wait for this time, then raise the pressure by the desired step size, wait again, and so on. A longer wait time is often better as it allows the system to stabilise, and allows more measurements to be taken. The wait time between steps and number of steps will both determine the experiment's length.
Below these inputs are four buttons. These allow overrides of the experiment's pressure sequence (i.e. overriding of the behaviour determined by the above four input boxes).
- Clear input will clear the selected input box.
- Zero the pressure will immediately set the system pressure to 0 kPa.
- Step the pressure will immediately increase the pressure by the given step size.
- Set pressure will immediately set the pressure to the starting pressure.
The sampling rate of each sensor can also be modified. Using the Select a sensor drop-down menu, you can select the desired sensor, and set its desired sampling rate in the Set sampling rate (s) input box. This sampling rate is given in seconds, and is the time between measurements for that sensor. The hardware has the capacity to take measurements fairly quickly, but for the purposes of data analysis and storage, don't make it too fast; a very fast sampling rate is not necessary for this kind of experiment.
The GUI also allows you to view data from the currently-running experiment. The [Experiment data (live)] (www.experimentwebsite.uwa.edu.au/values) page contains a continuously-updating data stream from the experiment, and can be accessed via the website's navigation menu.
