Distributed Monitoring System Based On Mscomm And Modbus Protocol

Modern measurement and control relies on computer, measurement and data communication technology, it has a wide application and involves many other fields. In practical application, there are often have huge data monitoring stations and the position decentralized. Besides, blocked by the environment and the operation of equipment, some points’wiring are very inconvenience, in order to satisfy the modern industry requirements, measurement and control system should be intelligent, decentralized and can remote transmission.This article analyzed modern measurement and control system application requirements and hardware requirements, presents a distributed system monitoring program. Take the PID adjustor or embedded data acquisition system as the bottom site node, constructed monitoring network consisted of computer and measurement and control node.The monitoring network can realize wired and wireless two kinds of data transmission, cable parts adopt RS-485bus, Realized multiple communication between PC and measurement and control instruments; Wireless transmission based on bluetooth technology, realized short-range wireless transmission. Data communication conforms to the Modbus protocol.By using virtual serial interface technology, the popular USB interface substituted for the not often configured COM port, the communication links, between PC and lower computer became convenientUsed Visual C++6.0compiled the PC software:realized the serial interface communication and data receiving by MSComm control; Real-time data stored in the database; computing and dynamic display measured parameter’variations curve; realized the data storage and foreign sharing by database technology; at last, driver the hardware equipment.The Pt100heat resistance had been chosen to collect temperature parameter, multiple spots monitoring system composed by measurement and control instruments XMT6XX,data transmit to the PC through RS-485bus and bluetooth module, practical inspected the functions of PC software, The tests show that message receiving reliable and handling timely, monitoring is convenientThe designed monitoring system communicate flexible, the system Configuration is simple and convenient, survey points can access, change or expand at will, can meet the needs of small-scale measurement and control or experiment. PC program written by vc++have friendly interface, the operation is simple, response timely, can deliver data to the use in form of curve or forms. applied database technology, based on this, the system can be used as a node and connected to configuration software, used in monitoring situations which have bigger regional span and more node number.