LightTools Enewsletter

Assume we want to compare two different LED options, and how output changes between different Lens Y and Lens Z coordinates. This is like studying the sensitivity of the system performance as a function of LED position and the LED itself.

To accomplish this with PSA, we can use PSA in Configuration mode. This requires each variable state to be evaluated as a separate configuration. PSA scans through each configuration, and conducts an evaluation and records the results. This can be a bit tedious to set up manually, especially for runs with many variable trial states (in our case, we have 18 total states to evaluate). Fortunately, you can use PSA to shorten the process by generating a list of the numeric variable values that can then be copied into the Configuration Manager.

In PSA, it is simple to add the Y and Z position as variables and generate a parameter scan list.

The following picture shows the variable states in PSA. Y will range from 0 to 1 in 3 steps. Z will range from -0.5 and 0.5 in 3 steps. In all, there are 9 combinations. A table shows the variable value for each trial.

Once the variable states are generated in PSA, you can convert each trial into a different configuration. To add these configurations:

1. In the property window for the lens’ coordinates, select the numeric field for Y. 

2. Right-click and select Add Configuration Item. You need to do this step two times, once for each coordinate (Y, and Z). 

3. After adding the configuration items, go to Edit > Configurations. Newly added items will appear as Y_1, and Z_1. You can rename these items. The required number of configurations is 18 [(2 LEDs) x (3 Y positions) x (3 Z positions)].

4. For each LED, go to the LED’s Properties > Display tab and make the Visible control a configuration item. On each source’s Emittance tab, make the Enabled control a configuration item. This will add four additional configuration items. Note that these are non-numeric settings for the source. In the Configuration Manager, they appear as checkboxes:

5. Back in PSA, copy the Y and Z variable values generated by the Uniform_Grid PSA mode. Use Ctrl+C to copy data from the grid or right-click and select Copy Grid Values to Clipboard.

6. Paste the values in Excel twice, one after the other. You can name each trial (avoid spaces). The first 9 entries will be for the first LED, and the last 9 entries will be for the second LED. Enter Yes to enable the appropriate controls, and No to disable the controls per trial.

7. Copy and paste the data from Excel to the Configuration Manager.

Once configurations are in the LightTools model, you can:

• Switch between different configurations quickly in the dockable Configuration control panel (View > Configuration Control Panel) in the main LightTools window. You can edit the configuration items for each trial individually.

• Run PSA in Configuration mode. Now you can scan the same parameters for each LED in one PSA run. In this mode, you can adjust the configuration item values to be nonuniform if you like, or choose a subset of the defined configurations to analyze.