DeviceNet is an on-site network with excellent construction performance. The new 2 covers a wide range of applications. Terminal components, actuators, control devices, etc. can be easily connected to the network, enabling equipment and production line design, manufacturing, installation, debugging, Maintenance and other links can reduce costs and save time, while further adding value to customers.
1 The principle of electrical control of carton printing machinery
Corrugated boxes are indispensable materials in the packaging industry and play an important role in the storage and transportation links. Corrugated carton production equipment should realize the processes of multi-color printing, slotting, die cutting, and semi-finished carton collection of corrugated cardboard. Combined operation, in addition to independent parameter setting and control, it also needs to monitor the status of other machines. Therefore, the fast data transmission function of one machine with multiple screens in the Ethernet mode of Delta HMI, in conjunction with the DeviceNet bus network connection, just meets this demand. The control diagram is shown in Figure 1.
Figure 1 Schematic diagram of industrial network control
DeviceNet is a more suitable industrial network solution, which uses Delta PLC's DeviceNet fieldbus to realize network integration of decentralized control. Each machine of this carton printing machine has 6 or more mechanical positioning. Since Delta SV series PLC currently only has 4 AB phase high-speed counters, each machine will use 2 SV PLCs. The small adjustments of each part are completed by the use of frequency converters and rotary encoders in conjunction with the high-speed counter of the PLC. Delta's SV series PLC and E series frequency converters have corresponding DeviceNet fieldbus solutions. as shown in picture 2.
Figure 2 Schematic diagram of work
The PLC of each machine is connected through the DeviceNet bus network to exchange required information and control commands with each other, so that one machine can monitor the status of each part of the device, control and adjust each part of the mechanism, or emergency stop remote The effect of other machines. In this way, on the one hand, it eliminates a lot of hard wiring at the same time, and on the other hand, it can realize interchangeability between similar parts of a variety of products, while reducing the cost and time of wiring and installing industrial automation equipment. Through the DeviceNet bus, the output frequency of the inverter can be adjusted in real time according to the displacement, the acceleration and deceleration linearity can be adjusted to achieve a smooth start and stop, and the displacement position can be measured with the rotary encoder to achieve the effect of precise positioning. At the same time monitor the working conditions of the inverter (including running status, output frequency, output current, alarm content, etc.). Through the touch screen of the Ethernet network, the PLC parameters of each machine can be directly set remotely, and the working status and alarm information of the machine can be collected. In this way, the direct interconnection through DeviceNet not only improves the communication between devices, but also provides a very important fault diagnosis function, and realizes the network interconnection of low-cost, high-performance industrial equipment.
2 control system configuration
The control system configuration is shown in Table 1.
Table 1 Control system configuration
The control architecture diagram is shown in Figure 3.
Figure 3 Control architecture diagram
Due to layout reasons, the number of encoders cannot be fully indicated. In addition, the position adjustment of each mechanism only works when the production material number is changed. Therefore, in order to save costs, the customer only installs two inverters for speed adjustment and positioning on each machine, and relies on external contactors to switch the motors of each mechanism. Therefore, only two position adjustment mechanisms can operate at the same time each time. Through the Ethernet network, the man-machine interface first accesses the PLC of the master station feeding part of the DeviceNet control layer, and then accesses each slave station PLC through the DeviceNet network. The 2 PLCs of each machine [industrial electrical appliances network-cnelc] exchange data through the RS485 PLC-Link mode. Address (NodeAddress) allocation is shown in Table 2 and 3.
Table 2 Address allocation 1
Since the equipment layer is an independent network under the respective PLC stations, the same node address can be defined without interference, but it is convenient for programming (for example, the same PLC program can be used for the same mechanism of color 1 to color 4).
Table 3 Address Allocation 2
3 DeviceNetBuilder software debugging
3.1 Communication connection
After setting the communication parameters, select "Network-Online" to search for devices in the network. When the search is completed, select the 00 master station network, and the detected network modules and devices will be displayed. Select the No. 10 master station network, the detected network modules and devices will be displayed, as shown in Figure 4.
Figure 4 Select the No. 10 master station network, the detected network modules and devices will be displayed
3.2 Module parameter setting
Double-click the DNET Scanner master module icon with the left mouse button to enter the "Scan Module Configuration" tool of the master module, set the scan list of the slave station, and the corresponding device (address) mapping table of the register:
are respectively connected to the master station PLC of Chromatography 1, Chromatography 2, Chromatography 3, Chromatography 4, Slotting, Die Cutting, and Collection, switch to each device layer network, and edit the address mapping table, as shown in Figure 5.
Figure 5 Edit address mapping table
After configuration, switch the PLC working mode to stop, select "Network-Download", download the set parameters to the DeviceNet module, after the download is completed, run the PLC again. Check that the "MS LED" and "NS LED" indicators of the master station DVPDNET-SL are green, and display the DeviceNet communication node number. In this way, the setting of DeviceNet is basically completed.
The entire machine of this equipment is designed and manufactured in accordance with high requirements, high speed, high efficiency, reliability and safety. The maximum feeding frequency is 200 sheets/minute, and the maximum paper feeding size is 1200×2400 (mm), which can quickly change orders. Convenient operation and adjustment, automatic zero and automatic reset. All gaps or positioning are digitally and electrically adjusted. Commonly used orders can be stored through the man-machine interface to realize quick order change operations. The technical highlight of the whole set of equipment lies in the application of the bus network. On the one hand, it simplifies the wiring work of equipment manufacturing, reduces wiring time, and improves wiring accuracy; when building or assembling equipment on the production site, special wiring rules and Detailed data, or special training, simplifies the equipment installation process; on the other hand, it improves the monitoring and maintenance efficiency of equipment users. The production and maintenance work can be reduced through the bus network. After the parameter setting is completed, the recipe saved to the HMI can be used. Reduce the adjustment and setting work of repeated production of the same process, standardize the production work, and facilitate equipment management. And can realize fast network fault information diagnosis, reduce system downtime. All in all, the industrial network is a good application tool.
About the Author:
Lin Xinghua, born in February 1974, graduated from Guangdong University of Technology with a major in Mechatronics. He has more than ten years of experience in automation technology and services. He is currently working in the South China region of Zhongda Dentsu, responsible for Delta PLC, HMI, AMD , AIC, ASD and other mechanical and electrical products technical support.