This counts both Remote Hack darts and Auto-hack darts. You can also reload saves and get credit towards the achievement. You should get this playing normally and exploring the levels.
During and after you get
https://www.trueachievements.com/a222431/protector-achieveme... there will be three or four hackable objects. There's a health station behind the gate, a Camera to the left of the gate, a vending machine across from the health station, and another health station on the far wall. It's a good place to hack and reload to get this trophy early.