A fluid control system for security relevant control and a fluid control actuator, a local control means for a fluid control system, a software module for a local control means of a fluid control system and a method for the operation of a fluid control system. The fluid control actuator (10) is controlled by control instrumentality means (30) of a local control means (50). A sensor (16, 17, 27, 41 and 42) transfers information concerning operational states of the fluid control system to the local control means (50). For this purpose there is a provision such that the local control means (50) determines from such information whether there is a security relevant situation and if necessary performs a predetermined function. The security relevant functions are integrated in the fluid control system so that same is able to be employed as prefabricated unit.