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Opening the Graphic Trigger Window Form an FDB Module

Let us assume that you have an FBD module, also containing the following instructions. Opening the Graphic Trigger Window Form an FDB Module-image_0Let us also assume that you want to know the values of c, d, and k, just before the ST k instruction is executed.Provided that you can never place a trigger in a block representing a variable such as Opening the Graphic Trigger Window Form an FDB Module-image_0you must select the first available block preceding the selected variable. In the example of the above figure, you must move the cursor to network 8, and click the ADD block.Now click Debug>/Add/Remove graphic trigger.Else, you can also insert trigger on the whole line; this means you’ll hit the trigger just before the first instruction of that line is executed. To do so, select the row by clicking the gray button on the left (the one with the row number inside) and add the trigger.In both cases the colour of the selected block will turn to green, a white circle with the trigger ID number inside will appear in the middle of the block, and the related trigger interface window will pop up. Opening the Graphic Trigger Window Form an FDB Module-image_0When pre-processing the FBD source code, compiler translates it into IL instructions. The ADD instruction in network 8 is expanded to:LD kADD 1ST kWhen you add a trigger to an FBD block, you actually place the trigger before the first statement of its IL equivalent code.