Dear Paul,
Yes. In SAM 2014.1.14, only the physical trough model supports subhourly simulations, and subhourly simulations require the special SMW weather file format. In that and earlier versions, there is a time step setting on the Simulator Options page. That setting is only active for performance models that can run with subhourly weather data -- you have to make sure the setting matches the weather file time step. You will notice that the setting is active for the other CSP models, but we only tested the physical trough model for subhourly simulations. In my quick test with the power tower model and a 15-minute weather file, the simulation failed. The data viewer in SAM 2014.1.14 and older versions does not support subhourly simulations: It only displays the first 8,760 rows of data, so you have to use different software to view the output files.
In the current version (SAM 2015.1.30), SAM determines the simulation time step automatically from the weather file by counting the number of rows in the file. There is no time step setting. The data viewer in this version supports subhourly data, so you can view the data in SAM.
Here are two other threads that should help shed some more light on these topics:
Time Step for SAM Model Simulations
Time Step -- Accuracy of the Simulation
Best regards,
Paul.