To configure a secure bus subscriber connected to a field bus in a secure control system, the secure bus subscriber being assigned a defined subscriber address, the invention provides a method having the following steps: an address allocation message is sent from a control unit connected to the field bus to the secure bus subscriber, the address allocation message comprising the defined subscriber address, the defined subscriber address is stored in a memory in the secure bus subscriber, and an acknowledgement message is sent from the secure bus subscriber to the control unit, the acknowledgement message comprising the defined subscriber address, where the address allocation message is sent on the basis of planning data for the secure bus subscriber connected to the field bus which are stored in the control unit. The invention also provides an appropriate control system.