Based on the description, I assume that the 'Log/Unlog selected signals' tab is grayed out and hence you are unable to see it.
To use the Simulation Data Inspector, you need to:
- First enable 'Signal Logging' in the Simulink Configuration Parameters
- Then label the signal you wish to log by double clicking and typing a name
- Click on 'Log/Unlog selected signals' tab in 'Record and Inspect Simulation Output'
Another way to log the signal is to right click on the signal and select 'Properties'. In the Signal Properties dialog that appears, select 'Log signal data'. Press OK and close the Signal Properties dialog.
For further information about Simulation Data Inspector, you can refer to the documentation by executing the following commands in MATLAB Command Window:
web(fullfile(docroot, 'simulink/ug/simulation-data-inspector-overview.html'))
web(fullfile(docroot, 'simulink/ug/customize-the-simulation-data-inspector-interface.html#bsof7or'))
Hope this helps!
