General Description: Why doesn't the simulator use the *.scl file if a signal in the file is not recognized?
When loading an SCL file, if the simulator sees a signal that it does not recognize, none of the SCL file is loaded and the simulator reverts to a "blank" SCL file. This can happen when an internal node is displayed in the Functional Simulator and added to the SCL file.
Then when a Timing Simulation is performed, the internal node may have collapsed and may no longer exist, therefore, this signal is not recognized by the simulator, so the simulator loads a "blank" SCL. This is an SCL file with the I/O signals present and with no stimulus defined.
The work-around is to save the SCL file containing the internal node as some other file name using either Windows Explorer or the Functional Simulator. Then, in the Functional Simulator, remove the internal node. The SCL file without the internal node can then be used in the Timing Simulator.