A method of enabling an operator of a process control system to determine the location of field users in the process control system, the method being performed by a field user presenting arrangement and comprising: - obtaining position data of the position of a field user in the form of a maintenance engineer, - obtaining the positions of objects (24, 26) in the process control system, - comparing the position of the maintenance engineer with the positions of the objects, - determining that the maintenance engineer is in the vicinity of an object if the distance between the position of the maintenance engineer and the position of the object is below a proximity threshold, - presenting the maintenance engineer on graphics depicting the process, where a maintenance engineer deemed to be in the vicinity of an object is presented at this object in the graphics, - receiving an indication that the maintenance engineer is in control of the object, - indicating this control in the presenting of the maintenance engineer on the graphics, - comparing, after the indication of control has been received, the distance between the controlled object and the maintenance engineer with a release threshold, - determining that the maintenance engineer has released the object based on the threshold being exceeded, - presenting the changed status of the object, characterised in that the process control system is in a first state at least in a section of the system in which said object being controlled by the maintenance engineer is provided, said first state being a safety state where the process is shut down completely or partly or running in a safety mode and by - instructing the process control system to change system state based on the determination of the release of the object. - obtaining position data of the position of a field user in the form of a maintenance engineer, - obtaining the positions of objects (24, 26) in the process control system, - comparing the position of the maintenance engineer with the positions of the objects, - determining that the maintenance engineer is in the vicinity of an object if the distance between the position of the maintenance engineer and the position of the object is below a proximity threshold, - presenting the maintenance engineer on graphics depicting the process, where a maintenance engineer deemed to be in the vicinity of an object is presented at this object in the graphics, - receiving an indication that the maintenance engineer is in control of the object, - indicating this control in the presenting of the maintenance engineer on the graphics, - comparing, after the indication of control has been received, the distance between the controlled object and the maintenance engineer with a release threshold, - determining that the maintenance engineer has released the object based on the threshold being exceeded, - presenting the changed status of the object, characterised in that the process control system is in a first state at least in a section of the system in which said object being controlled by the maintenance engineer is provided, said first state being a safety state where the process is shut down completely or partly or running in a safety mode and by - instructing the process control system to change system state based on the determination of the release of the object.