Remote Monitoring and Management System of CNG Flow based on Modbus RTU Protocol

A remote measurement, control and management system of CNG flow is presented based on a Modbus RTU communication protocol and non-contact IC cards. The system realizes parameter settings, CNG cumulative flow collection, history record inquiry, remote data transmission, real-time display, and sound and light alarm with the core chip STC89C516. Both the Coriolis mass flow-meter and the upper computer serially communicate with the microcontroller through the RS485 interface based on Modbus RTU protocol. The non-contact IC card and a password entered on the keyboard are used to modify the system parameters. A strict password protection system is designed to ensure data security in the IC card. The test results show that the system can smoothly run and safely, can accurately and flexibly acquire data, and can remotely transmit data and display. The system has the advantage of simple operation, high precision, strong anti-interference ability and low circuit cost, which have broad application prospects.