Automatic Meter Reading
Interoperability is the ability of a data collection system to exchange data with meters of different makes and the capability of the meter to operate or exchange data with different data collection systems. Collection, validation and transformation of data from large number of meters have to be carried out so as to realise the benefits from investments in the meter.
The process of integration of energy-meters with the IT-infrastructure attains complexity with numerous programming interfaces present for each meter type. To ensure interoperability of different makes of meters, open protocols have been evolved and standardized by American National Standards Institute (ANSI) and International Electrotechnical Commission (IEC).
A forum of meter manufacturers under the Indian Electrical and Electronics Manufacturers' Association (IEEMA) has also proposed Meter Inter Operability Solution (MIOS). In MIOS, each meter manufacturer provides a set of API’s which can achieve interoperability between meter data acquisition software of one vendor and meters of different vendor.
MIOS System Overview
MIOS based automatic meter reading (AMR) primarily depends on two Application Program Interfaces (APIs) namely API 1 and API 3. API 1 will accept commands from Host application, execute the requested job that of read or write meter data and write the resultant meter data as a binary file in proprietary format. In addition, API 1 will pass results as well as intermediate status messages to host application.
API 3 is generally invoked after API 1 successfully executes a read command. API 3, on invocation will read the binary file previously generated by API 1 and generate a corresponding XML file in CDF which is a standard format as per MIOS. The overall architecture of existing system is shown in Figure 2.
The modem connects to the central gateway and queries the meter locally for measurement data, converts it to unified readable format. The file is sent to the central server over a secure VPN channel. The m2m gateway implements the secure VPN channel. Modem contains the driver for the meter critical events such as tampers are communicated instantly to the central server. The central server can also pull data from the meters on demand.
All meter manufacturers will continue to maintain their existing design and communication protocols. However, they will provide API software analogous to a driver file which can be called by the Utility application software for provision of data in the desired format. This solution does not specify that all meters will supply the same information. It only suggests that the same parameter is represented in the uniform way.
-  Report of High Level Committee on Standardization of the Meter Protocol, Central Electricity Authority, Ministry of Power, Government of India, 2008