A method and also a control and data-transmission system is presented, with which the installation location of at least one safety bus component connected to the control and data-transmission system (10) can be checked.For this purpose, in two separate communications cycles, a respective position identifier, which had been allocated to the safety bus components (60) in a prior configuration process, is transmitted to each safety bus component via a non-safety communications control device (30). The safety bus components compare the position identifiers received in the two communications cycles to the contents of a memory, in which a reference position identifier has already been stored or which is still empty. Based on a comparison of the transmitted position identifier to the reference position identifier and the configuration dataset stored in a safety control device (50), it can be tested whether each safety bus component is connected to the predetermined installation location within the control and data-transmission system (10).