1、 A Monitoring System For PLC Controlled Manufacturing System Based On Fieldbus 1. Introduction The winding vacuum systems for plating metal such as zinc and aluminium on thin film are very common in the capacitance industry. The main goal is to increase as much as possible the film transport velocit
2、y while controlling the tension of the film. The tension and the speed of the film should be maintained at a reference value. The main concern is the coupling existing between film velocity and tension. There exist many sources of disturbances on the velocity (roller non-circularity, film sliding).
3、If the delivery speed fluctuates, then the treatment on the film becomes nonuniform. On the other hand inappropriate tension may cause wrinkles or even a film break. Once film break takes place, the operator needs open the winding chamber again. Obviously the pressure of winding chamber comes back t
4、o standard atmosphere pressure. And it will take about 20-30 minutes for winding chamber to reach the required pressure. Accordingly the output will decrease evidently. So a monitoring system to monitor tension fluctuation in order to avoid film break is very needful. CC-Link is a field network syst
5、em that processes both control and information data at high speed, to provide efficient, integrated factory and process automation. Using CC-Link enables users to reduce the amount of control and power wiring required in the complicated production line. Since users can select the suitable devices fr
6、om more than 354 field devices supported CC-Link it is easy to expand multi-vendor environment. As for the communication of speed, this enables the communication with the sensor input which requires a high speed response and intelligent devices which requires a large amount of data communication.As
7、one of CC-Links features, RAS functions such as, stand-by master function, detaching slave station function and auto return function enable recovery from the communication fault and the system debug at start up time.As for test and monitoring function, confirmation of the data link status, hardware
8、test and circuit test are available. The CC-Link network diagram is shown as Fig. 1. The CC-Link monitoring system is composed of master station slave stations personal computer inverter servo motors remote I/O units, ect. In order to meet the quest for automation and flexibility, many complex manuf
9、acturing systems are controlled by Programmable Logical Controllers(PLC). This is because that PLCs are adaptable, modular, user-friendly and acquired at low cost. And that winding vacuum film plating system is just such a complex manufacturing system. The paper presents an intelligent monitoring sy
10、stem based on CC-Link fieldbus which consists of upper personal computer and the lower Programmable Logic Controllers for the aim of control and information management. A new kind of technology using CC-Link fieldbus is adopted in this monitoring system. 2. Structure of The Monitoring System This fi
11、eldbus-based monitoring system has two arrangements including monitoring units in field and information management and control unit in control room. All intelligent monitoring units located nearby the winding vacuum machine have microprocessors, which have the following function as respective signal
12、 sampling, A/D conversion, data calculation, ect.Fieldbus is the most important connection between each discrete monitoring unit in slave stations and master station. Analog signal is superseded by digital signal for bi-directional communication. It is beneficial for an operator to realize control, verification and parameter setting in control room. The kind of structure, on one hand, increases the precision and antiinterference capability of the monitoring system. On the other hand, it saves the investment cost. The quantities of intelligent monitoring units should be determined by
