Although there are a variety of industry definitions, generally Automatic Meter Reading (AMR) is regarded as the reading of a utility meter by a means that does not require physical access or visual inspection of the meter. A typical AMR system has several main components: meter, meter interface unit (MIU), a communications network and host computer.
Normally, within an AMR system , the meter data is passed from the meter to an MIU, which may be external to the meter or integrated within the body of the meter. In addition to the meter data, other pertinent information may be stored within the MIU, such as any tamper or alarm conditions. This device forms the interface between the meter and the communications network.
Many communications networks have been used for AMR, including modulated radio frequencies (RF), telephone lines, or the electric power line itself. Depending on the network used, information from the MIU may be retrieved and stored in intermediate nodes or delivered directly to the utility. In the case of an RF network this may be a hand-held receiver, a mobile unit, such as a van, or a node on a fixed network.
The transfer of the meter data from the network to the utility may be instantaneous or stored for later transmission to the utility host computer. Often, on a fixed network, the data from the MIU is transmitted via a wide area network (WAN) back to the host computer. The WAN may be any variety of data networks, including; private data services or public data networks. Once the data is resident within the utility,then the meter and other retrieved information can be shared with other points on the system, including a customer service representative's PC or the central billing computer.
As mentioned, the meter data from the MIU can be transmitted over a variety of communications media including telephone, power lines, satellite, cable, and radio frequency (RF). Each of these methods has advantages and disadvantages as well as specific suitability. Many utilities who have implemented AMR have found that no single technology is universally available or viable for all their AMR needs and that often multiple communication technologies are needed to optimize a complete system.