- •Content
- •List of symbols and abbreviations
- •Introduction
- •1 Analysis of the subject field
- •1.1 Structure of the enterprise
- •1.2 Enterprise Information System
- •1.3 Statement of the problem
- •2 Оptions for possible methods of accounting and controlling electric energy
- •2.1 Electronic programmable device for remote metering of electric energy of the type «ets-m»
- •2.2 Electronic Multifunctional Multimeter «sem-1»
- •2.3 Characteristics of amr
- •2.4 General requirements for the amr system
- •2.5 Review of existing amr
- •3 Creating a software module
- •3.1 Selecting the language and development environment
- •3.2 Protocol of data exchange with a counter
- •3.3 Structure of the program module for processing the data of electricity meters
- •3.4 Sequence of execution of the request of the electric power meter data processing module
- •3.5 Software Implementation
- •3.6 Cyclic redundant code (crc)
- •Conclusion
- •List of used sources
3.6 Cyclic redundant code (crc)
Cyclic code checking is used to improve the reliability of data transmission. The meaning of control is as follows. The request is encrypted with a cyclic code. The result is added to the end of the request, and the entire packet is sent to the slave device. The slave performs the same actions on the request bytes and compares the result with the «CRC» of the received packet, and in the case of a positive result performs the required action. Then it forms a response message, exposes it to the same encryption procedure, «hooks» the received code to the end of the packet and sends it back to the host device. The host device performs the same decryption procedure, verifying the correctness of the received packet. The probability of detecting an error in one bit of the packet byte is 99.998%.
As an example, consider the calculation of «CRC» as a function written in the Java language. All possible values of «CRC» are placed in two arrays. One array contains all possible values for the high-order byte «CRC», and the second one for the younger one.
The text of the encryption function with the cyclic code «CRC» is given in Appendix B. Functions as parameters take a pointer to the message used to generate «CRC» (msg) and the size of the message in bytes (len), but returns a 16-bit value of «CRC».
Conclusion
As a result of writing the thesis work at the MinskEnergo branch of the Energosbyt branch, the main areas of activity were studied in detail, the organizational structure of the company and the tasks performed by employees of various departments were analyzed. Within the framework of the diploma work, a software module for processing energy meter data was developed and implemented. The software module was developed within the framework of the Automated System for Control and Accounting of Electricity.
The program module allows you to perform the following actions:
- perform connection to the electricity meters using the serial COM port «RS-485»;
- process the received data;
- display the meter readings in a user-friendly form.
At the stage of development of this software module, the most relevant and most suitable technologies for today have been selected:
a) Java programming language;
b) the Eclipse MARS.1 development environment;
c) implementation as a GUI application;
d) a library for working with the serial COM port jssc-2.8.0.
Ultimately, a software module was implemented that performs a survey of electricity meters, receives data byte packets and processes them, and outputs all meter readings to the monitor in a user-friendly format. Also, a user manual for the software module for processing electricity meter data and instructions for its use have been developed.
List of used sources
[1] Graduation projects (work). General requirements. СТП 01-2010. - Minsk: BSUIR. - 2010. - 169c.
[2] Internal resources of the Energosbyt branch.
[3] Concept of the subject area [Electronic resource]. - Access mode: http://www.rfpgu.ru/booksystem/page20.html.
[4] The official site of the enterprise «Minskenergo» branch «Energosbyt» [Electronic resource]. - Access mode: http://www.energosbyt.by/.
[5] GOST 8.437-81 Information and measuring systems. Metrological support. Basic provisions [Text]. - Enter. 1999-07-01. - Minsk: Interstate Council for Metrological Support Systems; M.: Metrological support, 1999. - 56 p.
[6] GOST 8.438-81 Information and measuring systems. Verification. General provisions. [Text]. - Enter. 2005-01-12. - Minsk: Interstate Council of Information and Measuring Systems; M.: Information-measuring systems, 2005. - 79 p.
[7] GOST 8.326-89 Metrological attestation of SI. [Text]. - Enter. 2007-05-28. - Minsk: Interstate Council on Metrological Certification; M.: Metrological attestation, 2007. - 98 p.
[8] ГОСТ 26035-83 Electronic electric power meters, electronic. General specifications. [Text]. - Enter. 2012-07-14. - Minsk: Interstate Council on Accounting and Control of Electric Power; M.: Electronic meters of electric power of an alternating current, 2012. - 154 p.
[9] The official site of the enterprise «Gran-System-S» [Electronic resource]. - Access mode: http://www.strumen.com/.
[10] СТП 09110.35.122-08 Typical requirements for the projects of regional AMR and ASCME consumers. [Text]. - Enter. 2008-11-12. - Minsk: Engineering department of RUE «Beltei»; M.: Typical projects of regional ASCAE, 2006. - 471 p.
[11] Official site of the Belarusian National Institute of Metrology «BelGIM» [Electronic resource]. - Access mode: http://belgim.by/.
[12] Rules for the Accounting of Electric Energy [Text]: (collection of basic normative and technical docs operating in the electricity metering area). - M.: Gosenergonadzor of the Republic of Belarus: Energoservice, 2002. - 366 p.