Why can't my Galaxy Tab S see a hdd (Samsung M3 1tb exfat format)?

[AC Question]

I recentre purchased a Samsung M3 hdd that I formatted in exfat to use with my Galaxy Tab S and my Galaxy S5 phone. When I plug it into my S5 using an OTG cable, the S5 recognises the USB mass storage and I can read and view the files. However, when I plug it into my Tab S, nothing happens or show's up.
Is there a reason for this and a wah to fix it?
I'm not that tech savvy so any help is much appreciated
Thanks
Paul

 

[FF22]

I don't have anything to plug in at the moment, but I thought I've gotten a prompt to MOUNT the external drive. You might explore Settings and see if something shows up under Storage or such.

 

[netslacker]

Could it be that the HDD draws too much power? There's OTG cables that have a microUSB connector for the purpose of providing power to the connected device, such as a HDD. It's possible the phone is capable of providing more power to the device while the tab isn't (?).