Abstract: A data monitoring system includes a display unit for communicating with an operation that has characteristics which are to be monitored, a recording unit located remotely from the environment of the monitored operation, and a local area network interconnect circuit for connecting the display and recording units. The local area network circuit allows multiple display units to be connected to a single pair of electrical conductors. Each display unit has at least one dual microcomputer configuration interconnected by a shared dual port random access memory. A third microcomputer is located in the recording unit for communicating over the local area network circuit with one of the microcomputers in the display unit.

Abstract: A data acquisition apparatus includes two microcomputers interconnected by a shared dual access digital storage device. One microcomputer obtains the data related to the monitored condition, stores it in the digital storage device, and modifies a status word which is monitored by the other microcomputer. When the other microcomputer detects a change in the status word, it takes the data from the shared digital memory and moves it into its own memory for subsequent use or transfer. The data acquisition apparatus also includes, in a preferred embodiment, analog switches and a digital to analog converter by which external analog devices can be controlled to change the monitored operation.