Thanks for the Hard Disk Sentinel report and your attention.
I examined, and as I see the drive (disk #2, the 900 GB drive) is currently "unassigned". So if I'm correct, it is not exported to Windows: the system can't read/write the drive.
Generally Hard Disk Sentinel attempts to enumerate the drives available for the system (so readable/write-able for the user) and list them in the order they appear in Windows Disk Management to allow easy identification.
There are exceptions of course:
1) when Hard Disk Sentinel found a RAID array, then it shows the RAID members and their status (not just the virtual drive, eg. "HP LOGICAL VOLUME")
2) when Hard Disk Sentinel found special drives, which are not exported to the OS (unassigned, spare, uninitialized, foreign, etc...) it tries to "connect" internally with an existing drive or RAID array, exactly to allow displayed (otherwise it would be not displayed because not available for Windows).
This is what you see: the disk (with its model, health, status, temperature and further information on the S.M.A.R.T. page) displayed - just seems associated with a RAID array.
This is generally normal and expected behaviour - sorry if this caused troubles or confusion. Will check possibilities to change this behaviour and/or outline better that this drive is generally independent.