A control apparatus for automatedly controlling a technical installation, comprising at least one module having at least a first module part, a second module part, and a third module part, wherein the second module part is a bus module part and comprises a housing, at least one first electrical bus connection on a first side of the housing for electrical connection to a first neighboring module part which is adjacent in the longitudinal direction, and at least one second electrical bus connection on a second side, opposite the first side, of the housing for the electrical connection to a second neighboring module part which is adjacent in the longitudinal direction, wherein the first module part and the second module part can be mechanically and electrically combined to form a first combined arrangement, wherein the first module part and the third module part can be mechanically and electrically combined to form a second combined arrangement, wherein the first module part comprises at least one first electrical contact, and wherein the second module part comprises at least one first electrical mating contact, which, in the first combined arrangement, makes contact with the first electrical contact of the first module part for electrical connection between the first and second module parts (102, 104), wherein the third module part comprises at least one second electrical contact, and wherein the first module part comprises at least one second electrical mating contact, which, in the second combined arrangement, makes contact with the second electrical contact for electrical connection between the first and third module parts (102, 106), wherein the first module part comprises a securing element with a securing engagement section which is moveable into a first and a second position, wherein the securing engagement section, in the first position, is in securing engagement with the second module part in the first combined arrangement, with the result that the first module part and the second module part are secured against one another, and wherein the securing engagement section, in the second position, is arranged in the first combined arrangement in such a way that the first module part and the second module part are detachable from one another, wherein the securing element comprises a securing actuation section by means of which the securing element, in the first combined arrangement, is moveable between the first and second positions when a force is exerted on the securing actuation section, wherein the securing actuation section, in the first position, is arranged in a first spatial region and, in the second position, is arranged in a second spatial region, and wherein the third module part has a blocking section, which, in the second combined arrangement, is arranged at least partially in the second spatial region, wherein the blocking section is designed such that the securing element, in the first and second combined arrangements, is prevented from moving into the second position, in which the first module part and the second module part would be detachable from one another, such that removal or detachment of the first module part from the second module part is only possible when the third module part has been removed.