The invention relates to a method and to an apparatus, which has been adapted to carry out the method, for the
coupling of a safety-critical process from a safe environment, which has at least two redundant
processing channels, to an environment which is not safe or to an environment which is safe but has fewer
processing channels. To this end, provision is made of a method which processes a data
record which is relevant to the safety-critical process, in particular on a protocol-specific basis, to form a respective safe protocol ( 14, 24 ) using at least two redundant
processing channels ( 1, 2 ) in accordance with identical laws, and forms a common safe protocol taking into account at least two redundant safe
coupling protocols ( 14, 24 ), to be precise by accessing a common (buffer) register ( 30 ) using each of the processing channels ( 1, 2 ), in which case a write
authorization is allocated only once for each register location, and, when writing at least elements ( 14 ') of the common safety-based protocol using a processing channel ( 1 ) with write
authorization, at least one further processing channel ( 2 ) is first of all used to check ( 25 ) whether these elements ( 14 ') are identical to one another, and access to the common buffer register for the purpose of storing these elements is enabled only when they are identical to one another.