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PE-iLAB - Help - Software

1. Introduction

The PE-iLAB is an educational system consisting of hardware and software to teach students the basic operation of switching converters as well as their digital control. The software (interface) is explained in this help file.

2. General Controls

The general controls are always visible and can be accessed independent of the currently selected tab. They include:

2.1. Connecting to hardware

The software will automatically detect all the available COM ports on the computer and try to connect to the first one. If that fails, the user can manually select the COM port where the hardware is connected to. The combo box for that is located at the bottom left of the interface. Once the connection to the hardware was successful, that combo box won't be accessible anymore and the background color of the "Receiving" label will be red.

2.2. Running and Stopping the converter

Clicking the "Run" button starts the converter with the currently selected options (Open or Closed Loop, Connected or Demo mode) and values. Stopping the converter can be done by clicking the "Stop/Reset" button or hitting ESC.

Note: The converter only runs with the interface. If it is closed, the converter will be stopped in any case.

2.3. Switching to Demo mode

The interface can also simulate expected values of the converter. In this case the hardware doesn't need to be connected. Demo mode can be enabled by checking the "Demo mode" check box.  The following extra controls will be visible: Demo mode is explained in detail here.

2.4. Moving averaging

By checking the "Enable moving averaging" check box the interface will perform a moving average of all the ADC measurements received from the controller. This will smoothen the display of the values in the "Measurements" group box but also slow down the display once there are fast changes of the values.

2.5. Data logging

If the "Always Log data" check box is enabled, the interface will always log data even if the converter is not running. See "Data Log Tab" for more information.

2.6. "Receiving" and "Sending" labels

A red background color of the "Receiving" label shows that the interface is receiving data (hardware is connected), otherwise the color is grey.

A green background color of the "Sending" label shows that the interface is sending data, otherwise the color is grey. It will always try to send data unless it is in Demo mode.

2.7. Status messages

Status messages are displayed on the left of the "Run" button to make using the software as convenient as possible. The following information is shown in separate lines:

3. Main Interface Tab

The main interface tab has all the controls to run the converter and the displays to get all the feedback from it. The user can switch between "Open Loop" and "Closed Loop", set parameters for each mode and watch the measurements in a table.

3.1. Open Loop

In Open Loop the duty cycle is the only parameter to be changed.

3.2. Closed Loop

In Closed Loop the output voltage has to be set first. The user can select one of the following controller types: Different gain settings are available and are enabled or disabled depending on the selected controller type.

3.3. Converter options

Note: The converter fails to run properly in DCM with very light load due to the driving circuit for the high-side MOSFET. In that case the output voltage will not stay constant.

3.4. Measurements

The following measurements are shown in a table:

The following calculations are also displayed in the table:

The table also has check boxes to change the update and logging functions. By default, all values will be updated and logged. But sometimes it is desirable to analyze only certain values. By unchecking the update check box of the other values, the values of interest are requested more often which can help for evaluation. Since the power and efficiency are calculated, they also won't be updated anymore if the respective voltages or currents are not updated. Furthermore the user can decide which values to log by checking or unchecking the "Log" check box. If updating of some values is disabled, but the user still wants to see if they have changed, the "Request all values at once" button can be clicked to update all values for one time.

3.5. Demo mode

When Demo mode is enabled, extra controls will be visible to set theoretical values for input voltage, output current and converter efficiency. In open loop the assigned duty cycle will determine the output voltage whereas in closed loop the assigned output voltage will set the duty cycle, both based on the input voltage. All the calculated outputs will show up in the "Measurements" table once the "Run" button is clicked.

4. Data Log Tab

When the converter is running, data will be logged. If "Always Log data" is checked, logging will continue at all times. The state of the "Update check boxes" in the "Measurements table" determines which data is logged. For performance issues, the log table will be invisible once logging is active and becomes visible again after logging is finished. The top of the "Data Log" tab shows the starting time of the log, a "Store data" button as well as a "Clear" button. Each log will be stored in a subdirectory called "Logs" if the "Store data" button is clicked or if the converter is stopped. The first column shows the time gone by in minutes (min):seconds (sec):milliseconds (ms) since the log started. A green background color of that column shows that the converter was running, otherwise it is light-red.

5. Options Tab

"General Options":

"Warning levels and Protection":

If the converter reaches the specified warning levels, the background of the related cells in the "Measurements" table will turn red as well as in the log. The user can also choose to have the converter automatically turned off from the interface once the warning levels are reached.

The DSP also has an over current protection for the input and output which triggers at 6A. This protection can be enabled or disabled from the interface. It is recommended to have it enabled. But for closed loop experiments where the controller is made unstable it can be disabled to avoid false triggers.

6. Calibration Tab

The voltage and current sensing circuits for each hardware have slightly different characteristics. Therefore the interface can be calibrated to show more accurate measurements of the connected hardware. If no calibration was done, the interface will use default values and display in the status message area that a calibration is recommended. The following values can be calibrated:

The calibration steps are: (repeat for each value to calibrate)

  1. Make sure a multimeter is set up to accurately measure the value for calibration (see Hardware help)
  2. Select value to calibrate from the drop-down list
  3. Adjust it to a suggested "Low" value (suggestion displayed in the numeric up-down box)
  4. Enter the exact value from the multimeter into that numeric up-down box
  5. Hit the "Acquire" button and don't change the value while the aquisition is in progress
  6. Adjust it to a suggested "High" value (suggestion displayed in the numeric up-down box)
  7. Enter the exact value from the multimeter into that numeric up-down box
  8. Hit the "Acquire" button and don't change the value while the aquisition is in progress
  9. Done! The calibration data is stored for that value.

Notes:

7. System Log Tab

The system log shows messages with time stamps from the interface since it was started. This helps to keep track of the history of the converter including possible faults. There are buttons to clear the log or save it to a file inside the subdirectory "Logs".

8. Appendix

8.1 Pictures of the Interface

Software Main tabSoftware Data Log tab

Figure 1: Examples of interface: Left: Main interface tab with converter running, right: Data Log tab showing measurements after converter is stopped

8.2 Keyboard shortcuts

Note: Starting the converter will focus either the "output voltage" slider in Closed Loop or the "duty cycle" slider in Open Loop. Thus after the user clicks the "Run" button, the respective slider can immediately be changed using the keyboard.

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