Command memory modules and pulse stage connectionsA special electropneumatic command memory module enables the combination of recurring start and stop functions as well as operating mode preselection conditions. A pulse stage chain consists of a number of memory elements (bistable valves), the pulse stage modules. They are interconnected in such a way that a switching step can only be triggered when it is its turn, i.e. when the previous switching step has been successfully executed and this has been reported back. A pulse stage module is assigned to each switching step or single cycle. Electropneumatic controllers according to the pulse stage method have a clear structure and are easy to service thanks to a built-in pressure indicator and manual override.