Wireless energy monitoring system using Zigbee

• Main Author: Luah, Shi Qin.
• Other Authors: Lee Peng Hin
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Electric power::Auxiliaries, applications and electric industries
• Online Access: http://hdl.handle.net/10356/53410
• Institution: Nanyang Technological University

This report describes the Final Year Project done by a final year student in Nanyang Technological University. The project ultimately aims to craft a Wireless Energy Monitoring System (WEMS) using low-power devices (i.e. Jennic Wireless communication sensor and controller boards). It will comprise of a database created on the internet server and a data link set up from a Power Meter (Schneider Electric Power Meter PM710) to a Personal Computer. Along the progress of the project, many researchers have been consulted. Many of them have experience, but in different aspects of the project, or used a set of different devices or a different application for programming the chip. The student also visited many website forums to seek after answers he was looking for, but to no avail. Forum posts were hardly replied. When posts were replied, the solution often given was too general or did little to help. The project focuses on interfacing the Power Meter which has a communication port which transmits data signals in the RS-485 (half-duplex serial communication method for devices and computers) electrical configuration, with a set of Zigbee network devices (Jennic JN5148-010 Evaluation Kit) which communicates with each other via Radio Frequency (2405-2480MHz). The protocol used for communication in the Power Meter is Modbus protocol. It is designed for a multidrop network based on master-slave configuration. In the beginning of its development, the protocol was more often implemented for the RS-232 configuration, but later on became more applied on RS-485 configuration. As for the Jennic devices, the chosen protocol to be used is JenNet. It has been built on the IEEE802.15.4 standards and customized for Jennic devices. The protocol is a simplified version of the Zigbee PRO protocol. For this project, the protocol has to be familiarised well enough, after which, the topology of the network and the application programming can be done with minimal amendments. The Application Programming Interfaces (APIs) used in the JenNet protocol are namely JenNet API, Jenie API, and Integrated Peripherals API. JenNet API is more suitable for advanced users to further customise their application while Jenie is used by beginners to program a usable application. In this project, the Jenie is often used as the backbone of the application coding. Complementing the Jenie API is the Integrated Peripherals API, which is used to control the peripherals of interest. There are many peripherals on the Jennic microcontroller module from the Serial Peripheral Interface (SPI) to the Analogue Peripherals. The Universal Asynchronous Receiver/Transmitter (UART) serial communication interface is not only used to program the Sensor Boards and Controller Boards, but also to facilitate data transfer in and out of the device. To solve the final piece for the puzzle, a component is needed which can interface with the RS-485 configuration of the Schneider Electric Power Meter communication port, and should also be able to interface with UART of the Jennic End-User Device (Sensor Board DR1048). This component is introduced the RS422/485 Transceiver + UART (MAX3140), which has been sourced for the project to solve a major complication. Things look fine in the beginning as the project sets out. It was not expected that the MAX3140 component raised many complications to be resolved later on. Some complications include the technical difficulties of programming the MAX3140 chip, the inappropriate size and unsuitable mounting. A MAX485 chip, together with some other components, was tasked upon the objective of interfacing the Power Meter and Jennic’s Sensor Board eventually. As a whole, the MAX3140 chip was far too good for the simple job. It allows more sophisticated customization and could be considered for an improvement of this project if further integration of the power meter and the wireless communication devices is required.