An industrial control system in accordance with the present invention is provided with a plurality of diverse controlled devices (e.g., fans, pumps, valves, solenoids, relays, etc.) for effecting overall system control. Each device has a unique set of logic control functions and/or command sequences and is connected, through an input/output interface, to a stored-program single board computer that provides device control and monitoring. The computers each include a central processor controlled by a composite or "master" program which is common to all the computers and which includes instruction sequences for all logic control functions and command sequences that exist within the system. A user alterable interconnection device (UAID) permits only those logic control function and/or command sequence portions of the master program that relate to a particular one of the controlled devices to operatively connect with the particular input/output ports associated with that controlled device. As the master program successively loops, only those logic control functions and/or command sequences that relate to the particular controlled device, as determined by the user alterable interconnection device, are operative to address the input-output ports associated with the controlled device and thereby effect device control and monitoring. The invention permits simple and efficient dedication of a plurality of single board computers having only one master program to an equal member of diverse controlled devices without the drawbacks normally associated with dedicated stored-program controllers.