In the last several decades network technologies, especially the Internet, have highly influenced the development of different aspects of our lives. The ability to spread information and acquire infor-mation from any place anywhere has given rise to new industrial sectors. The so- called “industrial networking”, which started as a network application, has lately become an industrial sector in itself. An important branch of it comprises meter reading.
Parallel to the technological developments, the user requirements form an important factor in the structural and functional improvement of such systems, and the evolving software and hardware solutions aim to solve these needs. Technological innovations like EEPROM, fast and high resolution processors, ADC etc., helped the transformation of fully electromechanical meters to electronic ones. The measurement units of electricity meters especially have become fully electronic. Such hardware developments have also created new possibilities for customer usage evaluation and pricing.
Together with all this comes a stronger need to increase performance and reduce the losses caused by a number of factors. Among them are losses due to unregistered usage, unlawful connections, measurement mistakes, meter reading mistakes, lack of an established customer usage surveillance system and mistakes caused by faulty documentation. On the other hand there is a pressing need for stimulating measure-ments like different tariffs for both individual customers and organizations.
In this work we present a system consisting of software and hardware components for meter reading compatible with the IEC1107 protocol. The easy-to-use package is especially aimed at reading different household meters (like electricity, water, gas). From here on the article is organized as follows: first we introduce the internationally accepted protocol for meter reading - IEC1107. We set out an overview of existing meter reading systems. Then we present our solution, which provides a possibility for transfer of data as well as transfer of control information from electronic meters via the Internet or an intranet. We believe it will present a good tool for government departments and companies in Turkey dealing with electricity provision, distribution and pricing. Developed in accordance with the Turkish Electricity Distribution Company (TEDC) 2004 requirements, it forms a good basis for further work in this field.
OVERVIEW OF SIMILAR WORK
There are quite a number of companies in the world working in the sector of meter reading that provide various solutions , . Some are based on index device reading, some use RF, power lines or GSM and some use connection over the Internet , . The introduction of electronic reading devices and the collection of data from them is also a current subject of research and development in Turkey. Our country is in the process of replacing a majority of electromechanical meters with electronic ones. Using these new devices, the possibilities of reading meter data remotely via the optic port will create a lot of advantages, both for the users and the companies.
According to the new specification which is being adopted by TEDC in 2004  manufacturers of electronic electricity meters should be able to meet the following requirements: “All information contained in the meter device should be accessible through the optic port, should be presented in a database form, all data excluding calibration data should be programmable on behalf of TEDC, a CD with the necessary software should be provided to TEDC, containing the password and it should be compatible with a version of the operating system specified by TEDC”.
This means that all electronic meters should be programmable, data should be acquired through the optic port or an index unit and should be either printable or transferable to a database in a specific format.
Some software companies in Turkey have already started work in this direction. One of them is Komtas . In the software they have developed, consumption information input may be done by three different methods (Fig. 1). The first is manual, and it allows the customer to read the meter value himself. The second method is automatic. With this method the information is recorded by an index device or an AMR system. The third method is using prediction and interpolation. It uses a predefined algorithm to manually or electronically predict the consumption value. The last method is suitable for meters that are situated in obstructed areas or are out of reach.
The software package creates an archive of the consumption data. This allows access to information collected in the past, and simplifies the necessary analysis. In addition, the system offers the ability to carry out low/high limit control according to a predefined value or formula. It gives an alarm showing values in different colours.
An example of a remote meter reading system is the internationally accepted AMR (automatic meter reading) system . It is a multilevel structured network which consists of the following modules: HCS (Host Central Station), Data Concentration Unit (DCU) and MIU (Meter Interface Unit). It is a more conceptual design opens to further development.
In general the system works as follows. There are two communication levels: the first is between the MIUs and the DCUs and the other is between the DCUs and the HCSs. The MIUs collect information from the meters; and the information is then transmitted over the power lines to the DCUs. The DCUs in turn transfer the information further to the HCS using PSTN (Public Switched Telephone Network), GSM network or RS232 interface or modem. The diagram of an AMR system is given in Fig. 2.
THE IEC1107 PROTOCOL
IEC1107 is an internationally accepted protocol for communication between an electronic meter device and a computer or index device. It works in one of four modes – A, B, C and D. The mode required for electronic meters is C.
Fig. 3 shows a simplified diagram of the IEC1107 communication protocol. The communication process starts with a request message sent from the computer or the index device. The message is sent to the optic port of the meter at a standard rate of 300 baud.
The contents of the request message are shown in Fig 4. As can be seen from the format of the request message, it starts with a ‘/’ sign (code 2FH), a character for communication request (?), (code 3FH), followed by an optional field for device address, an (!) character (code 21H) and ending characters CR (Carriage Return) and LF (Line Feed). If an address is sent with this request message, then only the meter with the specified address will send an answer to the request. If the address field is empty all meters will try to answer back, sending their identity information.
Fig. 5 gives the message format of the identity message sent to the computer or index device. The message starts with a ‘/’ character, followed by 3 bytes company identification flag (represented by XXX).
These flags are internationally distributed to meter manufacturing companies by The FLAG Association . The Z byte specifies one of the two modes accepted according to the IEC1107 protocol: data readout or programming mode.
To acknowledge the identification received from the meter, the so-called “Acknowledge message” is used, which is shown in Fig. 6. Depending on the value of the Z bit, the communication rate would be increased to 4800 baud and the data from the meter would be transferred to the computer or index device. The data is read via the optic post and contains the following fields: tariff-1, tariff-2, tariff-3, collective energy consumed for the last 12 months, max value of the last 6 months active energy, the number of times the Clemens was opened during the last 12 months, the time and date when it was opened, the first date of opening the device, device date, time and identity.
THE SOFTWARE PACKAGE
In order to demonstrate the work of the IEC1107 protocol, we have developed a software package using the C-Builder 6.0 platform. The software is based on a client server model. The software controls the meter reading done according to the IEC1107 protocol specification. The client part controls the connection and the data transmission realizing the remote meter reading process. Comport Delphi was used for the serial port communication between the computer and the meter.
The first step is checking the port state (Fig.7). If the port is not open, our program will bring up an error message. The second step controls whether the data read-out mode or the programming mode will be used. In the case where the user has requested a meter reading, the data-readout mode will be chosen. According to IEC1107 the communication starts at 300 baud, so the next step is checking the baud rate. Following is the Request message, illustrated in Fig. 4. If the expected identification information does not come back in 1500 ms then the program creates a time-out. After checking the identity of the meter an acknowledgement is sent back. At that point the rate is changed from 300 to 4800 baud to start the data transfer process.
With the help of this software package the data for all the previously specified fields in the user database is transferred in the requested sequence. The user interface part is shown on Fig. 8. All the data coming from a singe user is collected on one single interface.
REMOTE METER READING
In Fig. 9 we have presented an example of a multiple user remote meter reading system using either Internet or intranet. First of all, the client at the Meter Reading Centre has to determine the address and the port it wants to access – for example, “Meter -1”, “Port – 1”. Then it can start the reading process. The server part fulfills the requests, following the procedures of IEC1107. After the reading process is finished, the second stage is transferring the information to the remote client. This is done by the server that translates the data into a “string” format and, using TCP/IP, sends it to the client.
We have also developed a RS232 Multiplexing hardware using PIC16F84A. This hardware is used for selecting the port number by sending messages “Reading Meter Interface”.
RESULTS AND CONCLUSIONS
In this paper we have described a system for remote electronic electricity consumption meter reading. It consists of a software and hardware part. The work is based on the internationally accepted IEC1107 protocol and meets the requirements of the Turkish Electricity Distribution Company.
The system allows remote access either via Internet or an intranet. The reading and writing format of the data collected from the electronic meters is organized according to the requirements of TEDC as follows: meter serial number, meter production date, meter calibration date, meter identity, flag of the meter, device recorded date and time, tariff change date and time, meter battery status, demand period of meter, tariff information of the meter, tariff-1, tariff-2, tariff-3 and
tariff-4 power consumption and total power consumption, power consumption for the last six months, tariff-1, tariff-2, tariff-3 and tariff-4 power consumptions for the last 12 months, opening information for meter lid collected for the last 12 months. The user interface and some results are shown in Fig. 10 and Fig. 11.
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