Image Number 4 for United States Patent #4180860.
A universal module serves as the basis for creating a plurality of different embodiments of electrical display stations. The universal module is adapted to be connected to remotely located process control instrumentation from which it may receive and to which it may transmit analog and digital signals. The different embodiments are created by connecting to the universal module a selected combination of components such as status indicators, switches and signal adjusting devices. The universal module includes a micro-processor system having a central processing unit, a clock circuit and a non-volatile type of program storage unit with an address provided for each different embodiment. An embodiment selector provides the interconnection between the components connected to an embodiment and the circuits of the universal module and activates the address for the embodiment. The micro-processor system provides reference frequency and control signals which control the energization of the electrical display panel to display thereon the amplitude of signals in a selected variety of modes. The micro-processor system also performs all of the other functions prescribed for an embodiment such as controlling analog and digital multiplexing operations, controlling analog to digital and digital to analog conversions, routing of signals to status indicators, performing computations involving signals and the like.