How to use the simout block to log data in External Mode?

I am using Embedded Coder to program LAUNCHXL-F28379D Microcontroller. The simulation mode is set to external mode and I need to keep a log of the ADC output data. I tried using the simout block where the "Save Format" is set to "Structure With Time" and I got a struct when I stopped the simulation. However, the struct (1x1 struct with 3 fields) is empty. I am sure that the SCI is properly configured and the onboard Tx and Rx LEDs are blinking, showing that the data is transmitted back to the PC. So why the struct is empty?