We create tag with name State:
Depending on the tag's value we want to flash or not Rectangle object (instead of the Rectangle there can be other objects):
For example we want object is not flashing if our (State) tag's value equal 0, and flash with 1000ms frequency if tag's value not equal 0. We need to enable Flash property and fill it like this:
Click OK to confirm your changes and Run simulation to check your settings:
You can download this project here.