CONTROL SYSTEM

A computerized control system for a group of control devices comprises a plurality of combinations of control elements each including a set/hold amplifier receiving repeatedly from the computer a plurality of consecutive analogue signals quantifying the required settings for the control devices, a pneumatic line the pressure in which is determined by a current to pressure converter that senses the amplifier output, a plurality of pressure responsive valve setting devices each connected to the pneumatic line via a normally closed valve and operatively connected to one of the control devices, and valve actuators controlled by the computer for opening each valve to connect its respective assocaited setting device with the pneumatic line during each of the successive periods when the current to pressure converter is receiving an analogue signal quantifying the required setting by the control device associated with the respective associated setting means.