Method for controlling a wearable user device, which is a sensor and/or information device including establishment of a wireless communication link between the user device and a gateway, transmission of a connection event message to the process control system, wherein the connection event message contains an identifier of the user device, an identifier of the gateway and information on the successful establishment of the communication link, transmission of sensor data from the user device to the process control system, generation of at least one control instruction by the process control system in response to the received sensor data, wherein the control instruction is generated depending on the identifier of the gateway and depending on the received sensor data, and transmission of the at least one control instruction to the user device. Furthermore, a wearable user device as well as a control system are disclosed.