| Temperature is one of the most common and important parameter in various industrial production and scientific experiments. It is very necessary to monitor temperature accurately. The temperature monitoring system based on PLC have simple structure, high reliability and wide application. Touch screen is sturdy and durable, convenient to operate, and easy to communicate, so it is suitable for monitoring the temperature in industrial field. The Human-Machine Interface of using Lab VIEW as the configuration software is friendly and intuitive, it contains a number of tools and functions can be used for data acquisition, analysis, display and storage.According to the development tendency of virtual instrument system, this paper designed a multi-channel temperature monitoring system. It can realize the field temperature monitoring, remote temperature monitoring, and historical temperature data remote query of industrial sector. Field monitoring part need to connect the temperature transmitter to the PLC temperature module, use STEP7software design PLC temperature collection program, and establish communication between PLC and touch screen, to achieve the display of temperature curve on touch screen. The control room monitoring part need to collect temperature data from PLC with Lab VIEW and complete the real time display of temperature data in PC, then, store the data into Excel by Lab VIEW ActiveX Technology. Using OPC technology can realize the communication between PC based on Lab VIEW and PLC, then, PC can collect data from the PLC. Historical temperature data remote query part uses Mobile module as the client, uses control room computer as the server, through the TCP function of LabVIEW and LabSQL tool to realize the remote query of temperature data on the LAN.This research system uses the advanced electrical control technology, network technology and communication technology. The touch screen monitoring part has been tested in laboratory, and achieved the prospective effect. |
