Local web-server of telemetric system with modbus interaction sensors

Abstract

With the development of microprocessor components and, accordingly, a significant expansion of the use of computer technologies, remote measurement techniques are being developed. These include telemetry and remote control of technical systems or their components in industry, research, home appliances and other fields. In this paper, the author suggests how to build a local web-server based on a microcontroller with an ARM Cortex-M4 core, which can be interacted with via an http-browser with Internet access. The block diagram of the local web-server on the basis of the STM32F407 microcontroller with the ARM Cortex-M4 core is suggested. Hardware modeling of the local web-server with a two-processor architecture including the main controller and the Modbus processor with the RS-485 interface, which provides information exchange via the Modbus RTU protocol, is done. The main controller is equipped with an indicator system based on functionally programmable LED indicators, an LCD indicator of type BC1602A, a local keyboard, USB and SWD ports for debugging and programming of the microcontroller, an external Ethernet module providing a temperature sensor and the Modbus RTU relay module, which interacts with the main controller of the local web-server via the Modbus processor with the RS-485 interface using the Modbus RTU protocol. A software for interaction of the local web-server and a http-browser has been developed. The local web-server was tested with different types of http browsers, proved to be reliable and showed the response time which depends on the number of sensors and is less than 1 second in case of 9 sensors.