The modern and precise measurement of energy consumption is an important task for service providers. There are more standalone meters for registering utility consumption in every household. Personnel sent by the provider are responsible for recording them. The development of information and communication technologies gives us the opportunity to provide some kind of intelligence to these devices. If the meters can be read remotely and we implement other additional features, we realize the concept of smart metering.
My task in this thesis was to develop a field module for a telemetrics system, which can provide remote access to digital and analog measured data. Taking advantage of the feature of most measuring equipment being able to provide digital or analog channel information about the measured values, the device designed by me can be an additional tool to meters without remote access. Furthermore, with a built-in relay it may be controlled remotely.
In my thesis I developed the field module which is built around a Freescale Kinetis K60 microcontroller. With a Sagemcom Hilo V2 communication module, I provided connection to the GPRS network. In addition, I also developed an RS485 digital connection port and optically isolated inputs for meters with analog impulse output. For configuring the device, I created an optical service port, while for the remote control solution, I attached a relay to the module and made analog inputs for measuring phase voltage.
I configured the Freescale MQX real-time operating system according to the realized hardware and made both a GPRS task to handle the network connection and a task which is assigned to handle the transparent RS485 remote connection. I prepared the impulse input and optical connection management program. In order to provide a standard method for remote data access, I implemented the MODBUS TCP protocol. Finally, I connected a digital meter to the device to test its functionality in the real word.