An access control system controls access of a user to one or more operating functions of a technical installation. The access control system includes a receiving device configured to read access authorization data from a mobile data medium and an access control device configured to receive and validate the access authorization data from the receiving device. The receiving device continuously adds a dynamic portion to the access authorization data to create dynamic access authorization data and sends the dynamic access authorization data to the access control device. The access control device, in response to the dynamic access authorization data corresponding to a defined expectation, generates a release signal for those operating functions for which the access authorization data is valid.

Provided is a control system, comprising: a processing unit which executes a user program; one or a plurality of function units; one or a plurality of communication units which relay data between the processing unit and the one or the plurality of function units; and a reflection means which, when in the user program a variable is designated which has been associated with any of the data which the function units retain and which denotes the validity of the data, reflects, as the value which the variable denotes, a result of having aggregated states of each of the communication units which are present upon a transmission path from the function units which retain the designated data to the processing unit.

An access control system controls access of a user to one or more operating functions of a technical installation. The access control system includes a receiving device configured to read access authorization data from a mobile data medium and an access control device configured to receive and validate the access authorization data from the receiving device. The receiving device continuously adds a dynamic portion to the access authorization data to create dynamic access authorization data and sends the dynamic access authorization data to the access control device. The access control device, in response to the dynamic access authorization data corresponding to a defined expectation, generates a release signal for those operating functions for which the access authorization data is valid.

Provided is a control system, comprising: a processing unit which executes a user program; one or a plurality of function units; one or a plurality of communication units which relay data between the processing unit and the one or the plurality of function units; and a reflection means which, when in the user program a variable is designated which has been associated with any of the data which the function units retain and which denotes the validity of the data, reflects, as the value which the variable denotes, a result of having aggregated states of each of the communication units which are present upon a transmission path from the function units which retain the designated data to the processing unit.