I am thinking about adding a 480GB SSD drive to my DAW. The current disk controller is "Standard SATA AHCI controller. There are currently 5 devices attached to it. I have read this interface supports up to 32 devices.
 
Assuming I have an available bay are there any technical pitfalls adding a drive?

Shouldn't be any issues. Another option you have these days is PCI NVME which gets fixed into a slot of your chipset supports it. Or you can buy a PCI-Ex4 adaptor for that purpose.
 
Just make sure you check the boot order in your BIOS before restarting Windows as it can cause issues by trying to boot from an empty SSD drive.
 

You'll need SATA power (from the PS) and SATA data (to a free SATA port on the motherboard) connected to the new SSD.  
 
SATA power leads should already be in place (just need to find a free port on one of the leads - to plug into the new SSD).
 
As long as the motherboard has a free SATA port (most have at least six SATA ports), you're good-to-go.

Thanks.