Modbus Communication Research Articles

Distributed Measuring and Control System of Torque Rheometer

This paper presents a new distributed control system used in torque rheometer. It can overcome shortcomings in traditional control system of torque rheometer and optimize overall performance of the system. The measurement and control system was designed by modeling method. The enhanced PID control algorithm and integration separation digital PID control algorithm were adopted to improve dynamic response characteristics. The Modbus communication protocol was selected as data link layer protocol of communications network. The monitoring software was developed by Visual Basic. A large number of experiments demonstrate that the stability of system is improved greatly and maintenance and extension of instrument become easier.

Intelligent Bus Measurement and Control System Design Based on the TEDS

The article describes in detail intelligent bus measurement and control system (IBS) which are based on CAN bus, Modbus communications protocols and Transducer Electronic Datasheet (TEDS). Measurement and control system are constituted by the host computer, nodes, and the bus. The host computer is the master node of the measurement and control system, realizing the control of salve node, the display of measurement results as well as interaction with the user. The slave node consists of the signal processing unit, the TEDS information storage unit, communication unit and an AVR microcontroller, for the measurement of physical variables, actuator control and data interaction. The system has been successfully applied to large-tumor magnetic induction therapy equipment, which is very stable and reliable.

Continuous Vibration Monitoring System

This system is intended to monitor and analyze the signals coming from accelerometers, velocimeters and displacement meters in order to detect possible problems in the machinery being studied. At present, this application is monitoring the correct operation of SIDERCA’s mandrel retained mill.This system allows an early detection of abnormal signals coming from process equipment, thus helping predictive maintenance people to anticipate to future problems reducing operation down times and costs.This system digitalizes the signals coming from the field sensors and calculates the RMS value, kurtosis, frequency domain spectrum (through FFT) and several other factors. It also allows to perform velocity and displacement measurements by means of numerical integration. Complete information is stored in temporary and historical data bases to enable further analysis.By means of ModBus communication protocol, the system is connected to different PLCs in order to obtain complete process information.This application is built on a micro kernel, multitasking real time operating system running on a 486 DXII-66 industrial PC with a 200 kHz 16 channels data acquisition card.