Monitoring System on the inverter

Abstract: With inverter Technology and the development of industrial production, the drive speed as an important means of communication in the Industry have been widely used. Inverter Applications not only greatly improve the efficiency of production processes and energy-saving effect, but remote monitoring in the control room running the drive, to minimize the burden on operators to improve the working environment, and improving the level of automation. In this thesis, the industrial production process control needs of the inverter as the background, theory and practice combination designed based on PLC and inverter control system configuration software.

Keywords:: PLC control system drive
First, the status of the drive Application
Drive productivity and economic development is the rapid development of world product. In recent years, AC frequency conversion Technology with rapid development in China, Frequency Control in the speed range, speed accuracy, communications, energy conservation, efficiency and other areas is another way of AC variable speed can not match. AC motor drive is based on the development and Application of frequency control, and it small size, light weight, versatility, using a wide range of protection functions and , high reliability and easy operation, by the iron and steel, metallurgy, mining, petrochemical, pharmaceutical, food, textile, printing and dyeing, mechanical, electrical, building materials, paper, etc. welcome to use the drive after the economic and social benefits are very significant.

PLC Technology is a computer Technology based on new industrial control devices. In recent years, PLC Technology in a variety of industrial process control, production line automation and control of various electrical and mechanical integration equipment has been widely used as industrial control field a very important Application of technology. current PLC has been widely used in petroleum, chemical, metallurgy, light Industry, mechanical, electrical and other industries, to achieve a logical, step, numbers, robotics, automatic control of analog, etc. . With the advent of the digital age, software will continue to penetrate to the hardware, continue to use the software instead of hardware to achieve intelligent control and manufacturing automation. PLC technology is the computer hardware, such as areas of infiltration to relay the outcome of software instead of hardware, with software instead of hardware relay system so as to provide a convenient connection and transformation, can improve efficiency cost savings. PLC can be said specifically designed for industrial harsh environment of small computers, the field of industrial control has become the dominant basis for automation equipment. PLC technology has three major technologies for industrial automation (PLC technology, robotics, computer-aided design and analysis of one of the pillars.

Second, the system of work process analysis
Assumes that the system software and hardware required has been correctly configured and connected, so that the necessary equipment required for the normal parameters were set correctly, to power the device, run the configuration software and WinCC V5.1 and has been downloaded End communication control program S7-200 PLC CPU224 XP. open the Preferences screen, set the operating parameters for the drive. As in the configuration when connected to each parameter of a process variable, and the process variable is given a MODBUS address, the MODBUS address and S7-200 PLC CPU memory address of the variable has a certain relationship between the. When the operator to drive through the monitoring computer to set a parameter, this figure through the WinCC communication drivers within the provided passed to set the channel process variable with the corresponding S7-200 PLC CPU224 XP variable storage area. stored in the S7-200 PLC CPU224 XP store the number of variables and then by the USS protocol control program under the control of the serial communication port 1 pass to drive. operational control screen in the drive inverter can control the running, stop and so state. When you click on the words "Run" button in the word, because this button is the process of a binary variable with a connection is established between The binary process variables and S7-200 PLC CPU224 XP corresponds to an input point, click on this button is equivalent to connect the S7-200 PLC CPU224 XP an input point, when the ladder program with the input point corresponding to the normally open contact closure to block flow through the drive PLC output point connected, the primary drive is the same as pressing the run button on the control panel, so the drive up and running. Similarly, the drive can run control screen, press the stop button, increase in the frequency button, buttons, and reduce the frequency to control the drive fault reset button.

In the inverter operation status monitoring screen, can monitor the inverter output current, output voltage and operating frequency. The amount has been given by a MODBUS address of the process variables and S7-200 PLC CPU224 XP store the address of the variable establish a correspondence. system to work through the control program can be a time interval to the actual operation of the drive to read the data. These data are stored in the PLC, the first variable in the store, then go through a transformation between the serial communication port by the PLC passed to the WinCC configuration display screen.

In addition, WinCC V5.1 configuration software features a powerful real-time database archiving process values ​​can then be in the form of a table or trend output current process value or archived data, which shows the inverter output voltage and current and the operating frequency of the real-time operating curve, historical operating curve.

Third, S7-200 PLC and inverter to achieve communication between
1, data communication principles
CPU and external data communication for data exchange that is mainly parallel communication and serial communication in two ways.

(1 parallel communication. Parallel data communication simultaneously transmit all bits can be words or bytes in parallel. Parallel communication speed, but the communication lines with multiple, high cost, it is not suitable for long-distance communication.

(2 serial communication. Serial communication is one of a sequence of data transmitted, only a few with very little communication lines. Serial transmission speed is low, but the transmission distance can be very long. In the PLC network to transmit data the vast majority of serial way.

Communication of information both from the view interactively, serial communication can have the following three:
① simplex communication: information transfer in one direction only and not the opposite direction of the interaction.

② half-duplex communication: communicating parties can send (receive information, but not two-way transmission.

③ full-duplex communication: Communication can both send and receive messages, both sending and receiving devices simultaneously.

Simplex bilateral exchanges of information can not be achieved, it is rarely used in the PLC network, and half-duplex and full-duplex data transmission can be realized both sides, so many Applications in the PLC network.

Serial communication, the transmission rate in the transmission of bits per second (bit / s to represent, called bit rate (bit / s. The standard transmission rate of a common 1200,2400,4800,9600 and 19200 bit / s and so on. Links to Research Papers Download http://www.hi138.com 2, the work of serial communication
Serial communication uses a well-designed hardware and software protocols.

Software specified in the agreement of the signal baud rate, word length, the meaning of that, but also by the designer according to the definition of special needs. Typical serial communication hardware standard RS232 and RS485 communication interface is, they define the voltage impedance, but does not define the software protocol.

RS232C in 1969 by the American Electronics Industry Association EIA serial communication interface released. This standard is applicable to personal computers and peripheral equipment, the interface between. RS232 designed only for two not far from the communication between devices, Its characteristics are used to improve signal level range, improve the ability to suppress noise, which provides the terminal equipment (DTE and communications equipment (DCE way information exchange between and function. Today almost every computer and terminal devices are equipped with RS232C interface, each RS232C interface has two physical connectors (plugs, DTE side (pin side for the public, then it is the mother, DCE side (side of the pinhole for the mother, then it's for the public. The actual use, computer's serial port is male plug, plug PLC-side for the mother, and they are connected to the plug just the opposite.

In many industrial control and communications systems, often have more than two o'clock straight interconnection, and in most cases, at any one time is only one main control module (point to send data, other modules (points) at the receiver the state of the data, so they produced a master-slave structure of the RS485 standard. RS485 standard work in half-duplex mode, it is for communication between multiple machines designed, with high noise immunity, and allowed to work in ultra-long haul occasions (up to 1000 meters. All the standard Siemens converter has a serial interface using RS485 two-wire connection. a single RS485 link can connect up to 31 inverters, and drive according to the address or information can be found using radio frequency required. link the need for a master device, and each inverter is the affiliation of the control object.

References
[1] Ying Lu Wei Cai Xingjian layman Siemens S7-200 PLC. Beijing Aerospace University Press, December 2004.

[2] Su Kunzhe Chinese visitors to learn how Siemens WinCC V6.1. Beijing Aerospace University Press, May 2004.

[3] Wang Dongbin Yao Jiwen Principle and Application of PLC. Machinery Industry Press, June 2002.

[4] WANG Zhao Chun-power electronics technology. Machinery Industry Press, January 2004.

[5] Chen Boshi electric drive control system. Machinery Industry Press, June 2000.

[6] Lei Liwen Zhu Xiaohua Microcomputer Principle and Interface Technology. Electronic Industry Press, June 2003.

[7] SIEMENS.MICROMASTER410/420/430/440 inverter 0.12KW to 250KW product samples DA51.2, 2000 years.

[8] SIEMENS.MICROMASTER440 general-purpose inverter 0.12KW to 250KW with Guinness, in December 2003. Links http://www.hi138.com Research Papers Download