Patent US 4,454,596

A display and control element is described which comprises several lighted push buttons which are--if necessary--mutually resetable and are mounted on a board insertable into a casing. The operating of the individual lighted push buttons as well as the optional mutual resetability is electrically determined by means of circuits. The arrangement and setting of such circuits is adjustable without change of the wiring by means of code switches, crossbar distributors, plug-in connectors, etc. or by means of the program (software) of a microprocessor which preferably is mounted on a separate plug-in board. For more complicated plants to be controlled several such elements may be combined in a casing and, if necessary, also several such casings may be connected to each other by means of data lines. In such a case it is advisable to locate the microprocessor in a central casing, so that such a microprocessor can centrally control all the display and control elements with respect to their operation and their mutual resetability. In view of the versatility of the display and control element according to the invention such element may replace the several display and control elements of different construction being necessary according to the prior art for the control of for example air conditioning plants, thereby saving costs with respect to construction as well as maintenance.