My Intuos5 goes to sleep unexpectedly while working. The battery is charged & connectivity is fine.

for Mac

1. Set the Power Saver of your Mac to Never.

Click the Apple logo > System Preferences > under Hardware, click Energy Saver > click Battery Tab > slide the switch for both Computer Sleep and Display Sleep to Never > do the same on the Power Adapter tab.

2. Set the Battery Power Saving Mode to 20 minutes.

Click the Apple logo > System Preferences > Wacom Tablet icon > select Functions in the Tool box > click Wireless tab > slide the switch to 20 minutes.