You can swiftly find a source signal of any expression in the virtual signals by using the cross reference function. Particularly, when using the signal name as reference in the expressions instead of the signal number the conclusion on the origin of the signal is not easy.

In order to find the signal source follow these steps:

1. Click on the little question mark button in the row with your expression.

   
   
   
   
   

2. The diagnostic window opens, showing the details of the expression. Double-click on the signal whose origin you are looking for.

   
   
   
   
   

3. The view switches immediately to the interface and module in the I/O Manager. The signal in question is highlighted.