US Patent 9760075 Location dependent control access in a process control system

A method of accessing an element in a process control environment using a portable communicator includes defining a plurality of control areas within the process control environment, determining a position of a user operating a portable communicator with respect to one or more of the control areas, establishing an identity of the user, and selectively allowing the user to access an element within the process control environment via the portable communicator depending on the determined position of the user with respect to the one or more control areas and on the identity of the user.