1. A control system having: a plurality of control modules connected in tree-configuration hierarchical relations successively branching from top to bottom, and means for transmitting prescribed commands to these control modules; wherein: there is provided a command write register group having, in correspondence with the aforementioned control modules, a plurality of command write registers in which commands can be written; the aforementioned transmitting means has means for writing commands in the command write register group in accordance with the aforementioned tree-configuration hierarchical relations; and this writing means includes means for expressing the tree-configuration hierarchical relations by turning intersections of a switch matrix on or off prior to writing a command, and means for writing a prescribed command in the command write register group in accordance with signals instructing said writing, these signals having arrived via these intersections.