Application of the hottest PLC in remote monitorin

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The application of PLC in remote monitoring

1. Introduction

traditional remote monitoring only has the function of data acquisition, and it will be inadequate when real-time control and data processing are required. As the core component of industrial control, PLC is more and more powerful in network and communication, and has the functions of data acquisition, real-time control and data processing required by remote monitoring. With the increasing market share of domestic PLC, the price of PLC is also more advantageous than before. Using PLC as DAS system or using PLC platform to develop data acquisition system will be the general trend or quite attractive choice. The V80 Small PLC of Davidson company has many successful applications in heating, traffic monitoring, building monitoring and other industries

the application of PLC in data acquisition and remote monitoring industry is illustrated by taking a heating monitoring in Northeast China as an example

2. Remote monitoring system

schematic diagram of heating remote monitoring system is as follows:

Figure 1 Schematic diagram of heating remote monitoring system

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v80 series PLC collects the temperature, pressure and flow of each heat exchange sub station on site, and controls the heating flow according to the collected data, so as to achieve the purpose of energy saving. According to the change of outdoor temperature, the return water temperature of the secondary pipe is controlled in time by adjusting the opening of the electric valve of the primary pipe, and the operation parameters of each heat exchange station are always within the given range by dispatching the given control curve. At the same time, the central monitoring room dispatches and remotely controls the electric valves of the sub station to adjust the operating parameters. The system is equipped with GPRS DTU, which can realize temperature control and remote control of frequency conversion of make-up pump. The upper computer adopts the configuration software of Kingview, which greatly reduces the cost of modified special materials combined with the database, stores and analyzes all data, and can cooperate with the optimization software for priority control

3. PLC features

Figure 2. Schematic diagram of V80 system structure

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in view of the various problems mentioned above, this paper proposes a more superior scheme, with the following characteristics:

1. Network communication function

v80 series PLC can support more than two communication ports at the same time, and RS485 communication port can be used to form a control network to group multiple V80 small PLCs into the same fieldbus network, A gprsdtu module is connected to the master PLC to provide a transparent upper channel for the monitoring network. Using GPRS DTU instead of wireless RTU can greatly reduce the cost of large companies, which are mainly committed to the production and research and development of lithium-ion batteries and systems for new energy vehicle power. Modems can be selected at the installation position of the adjustable reversing switch where the line is laid, so as to optimize the cost of the whole system

2. CPU module function

m32dt module is a CPU module with 16 channels of digital input and 16 channels of transistor output. It has two communication ports, one RS232 and one RS485, with MODBUS master-slave communication protocol and free communication protocol inside. It can communicate with various HMI or various configuration software. The communication protocol library file provides many conveniences for manufacturers to develop host computer software by themselves

m32dt is equipped with flash memory, which can store various parameters locally, and also has the function of power down holding, so as to ensure the reliability and convenience of use. The high-speed operation speed and complete mathematical operation ability make it more suitable for communication and analog processing environment

3. Strong anti-interference ability

the wide temperature and wide power supply design of the whole system makes it easy to operate in harsh environments. V80 series products have passed CE certification

4. Programming is simple and convenient

v80 series PLC programming language supports IEC standard, which can facilitate programming. At the same time, it supports programming, that is, it can modify and debug the program in the running state, which provides convenience for the upgrading and expansion of the monitoring site

5, high cost performance

v80 series PLC has price advantages over data acquisition modules with the same number of points, and its graphical programming function makes it a powerful distributed monitoring platform

4. Conclusion

taking the remote monitoring of heating as an example, this paper introduces the integration characteristics of V80 series PLC, communication protocol and third-party products, and explains the application of V80 series PL and C in the data acquisition and remote monitoring industry. The actual operation results show that V80 series PLC is an ideal choice for customers to integrate acquisition, control and remote monitoring

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