Patent ID: 6985831

Claim:
A system for sensing a characteristic at least one remote location and transferring data indicative of the sensed characteristic to a data base located at a central location, remote from the remote location, said system comprising: at the remote location: a sensor for producing a digital output reading indicative of the sensed characteristic; memory for storing the digital output reading; a first communication unit for sending and receiving information to and from the remote location and the central location; a processor for controlling the first communication unit to send and receive information, controlling the sensor to produce the digital output reading and storing the digital output reading in the memory; at the central location: a second communication unit for sending and receiving information to and from the first communication unit at the remote location; a data base for storing data received from the remote location; wherein the processor causes the digital output readings to be stored in the memory until the digital output reading can be transmitted to and received by the second communication unit; and wherein the processor determines whether or not data can be transmitted to and received by the second communication unit at the central location, and, controls the first communication unit to send data corresponding to the digital output reading when the second communication unit can receive the data; a plurality of field instrument units, each said field instrument unit housing the sensor, the memory, the first communication unit and the processor, and wherein each field instrument unit is located at a separate remote location geographically separated from each other for sensing characteristics at each of the remote locations and transferring data indicative of the sensed characteristics of the corresponding remote location to the data base located at the central location; and wherein the plurality of field instrument units are arranged in a star topology with the data base of the central location located at the center of the star topology.