I. Preface This project is a centralized control system for multiple vulcanization tanks in a vulcanization plant of a synchronous belt factory in Zhejiang Province. The customer requested that the system be able to monitor the working status of the vulcanization tank in the entire vulcanization plant in the monitoring room and realize remote human-machine interaction; To be able to operate on site before each vulcanization tank, carry out on-site human-computer interaction. For on-site human-machine interaction equipment, due to the large number of vulcanizing tanks, the customer put forward the requirements of “functionality meets the requirements and the lowest costâ€. According to this requirement, we designed a master and slave control system consisting of an industrial PC+text man-machine interface+PLC controller. The practice has proved that the system satisfies the requirements of the customers.
Second, the control system design program Control system hardware components shown in Figure 1.
As can be seen from the figure, in the control system, the master is an industrial PC, and the slave is a POP-HMI text man-machine interface + programmable logic controller (LG PLC) system; the POP-HMI text display is Low-cost HMI products for the requirements of the site's human-machine interaction. POP-HMI is a text human-machine interface product independently developed by Shanghai Boshen Electronics. The text display adopts a monochrome (3.7â€) dot matrix LCD display and provides Chinese, Western, digital and simple graphic display; The keyboard provides digital, parameter input, custom input, etc. It can be easily connected to various manufacturers' programmable control (PLC) and all kinds of electrical equipments with serial port communication capability, which is the best choice for low cost field control equipment. -HMI's configuration development software is based on Windows platform, friendly interface, easy to use, developers can master the use in a short time.The programmable controller is LG K120S series PLC, this series of PLC can support RS232 and RS485 dual serial port at the same time Communication and communication are powerful.
The LG PLC that controls each vulcanization tank is remotely connected to a computer through a RS485 bus of its communication port and a computer to form a centralized control system. During the communication process, the main control computer is the master station, and the vulcanization tank PLC is the slave station. The communication protocol complies with the MODBUS communication protocol. The number of slave stations is 12 before. The POP-HMI text display is connected to the LG PLC through the programming port (RS232) of the LG PLC. The communication protocol is a dedicated protocol of the LG PLC.
Third, the control system function description The control system, the main control computer is responsible for the vulcanizing tank in the vulcanization process parameters set, work status display, fault alarm display records and centralized management of production status. The POP-HMI text display is responsible for the on-site working status display, parameter setting and modification of each vulcanizing tank; the PLC controller is responsible for completing the sequence control of the equipment, the acquisition and input of sensor signals and the communication connection with the main control computer.
The control system has two manual and automatic work modes. In the manual operation mode, the POP-HMI text display on each autoclave operation box is used for the manual parameter setting operation and on-site status display of each autoclave. In the automatic working mode, the vulcanization process parameter setting is completed by the master industrial computer; the working status and failure alarm information of the autoclave can be simultaneously displayed on the host computer's monitor and on-site POP-HMI text display LCD screen in both modes. On the display.
Fourth, control software function description
1ã€Monitor room industrial PC software function
* Multiple vulcanization process parameter settings
* Multiple sulfide tank working status monitoring
* Multiple autoclave failure alarm display and record
* Generate work report and print
2. On-site POP-HMI text display software function * Single vulcanization process parameter setting
* Single sulfide tank working status monitoring
* Single fault alarm display and record
V. Concluding remarks The master-slave control system has been debugged. It has been proved that the control system slave station has selected the POP-HMI low-cost small-scale human-machine interface, which meets the user's requirement of “lowest functional realization cost†for on-site human-machine interaction. Through the design and development of the control system, a typical application example is provided for the low-cost human-machine interaction on the equipment site for the POP-HMI small text human-machine interface.