RHEL client 7.5 hdparm question rc.local

Hello all,
After a resume from suspend:
- hdparm has lost his config option: 'hdparm -S 1 /dev/sdb'
And is constantly spinning. It is a hdd caddy instead of the cdrom drive.

The rc.local script is working perfect on a normal startup. How can I read the rc.local settings from a resume?
kindest regards, Marco