With the rapid development of the concept of industrial 4.0 and smart manufacturing, production mode of information technology & big data monitoring is rapidly popularizing. Due to advantages of high quality roller coating and high return on investment, UV rolling coating production automation speed up the process transformation from the traditional rolling coating. At the present stage, most rolling coating production in our country is mainly controlled by single machine equipment, although there is one line production, but it does not have the function of whole line control and adjustment, which results in the extensive labor works, and when the equipment fails, there is no linkage interlock stop. The equipment damage cost and maintenance cost are high. What’s more, the difficulty of recruiting and the improvement of salary level now is also a trouble to the rolling coating industry during nowadays labor structure.
In order to realize the centralized control of the UV coating production line, the action linkage and adjustment of the whole line shall be ensured, and the scheme shall be formulated according to the requirements of the user. In this scheme, there are 15 sets of single machine equipment, including 2 dust removers, 1 heavy duty dust feed machine, 2 dual wheels coating machines, 2 dual lamp dryers, 1 three lamp dryers, 5 conveyors and 2 sanding machines. The sanding machine belongs to the products purchased by users and is included in the control scheme of the system. The sanding machine needs to be equipped with communication control interface to the system control.
Figure 1 Field Electric Cabinet (partial)
3. Control system and network configuration
● Haiwell PLCs are adopted, chooses master with Ethernet interface, bus communication uses industrial Ethernet to communicate, communication protocol MODBUS/TCP protocol, fast transmission speed, strong real-time control. Each stand-alone device selects the appropriate model of PLC according to the actual number of I/O counts.
● Basically, the conveyor equipped no PLC, but control by nearest equipment, So the control interface of the nearest device of the conveyor should reserve control interface for conveyor, for reducing the cost of bus control.
● To improve the reliability and stability of the system, as well as the data processing ability, communication rate etc, this system uses a high-end PLC as the master control PLC to process all the data.
● The single machine equipment of the system is equipped with man-machine interface for monitoring, any single machine can be controlled and adjusted on the spot.
● The monitoring system uses a 10-inch touch screen and PLC for monitoring, and can also equip with Haiwell Cloud Box (CBOX), large screen controller (TVBOX) (large screen controller to achieve centralized control. In this system, the solution with Haiwell Cloud Box with large screen controller. The main control system has the function of cloud, can carry on the remote debugging program, use mobile phone for remote monitoring the equipment status and so on.
● The network communication adopts 12-16 portals industrial Ethernet switches, the network cable adopts the industrial-grade shielded Ethernet communication line, and the switch needs to be installed in the special electric box. The network cable needs to take iron pipe or separate wire slot when installed in field to improve anti-jamming ability.
Figure 2 system networking
4. The function of process control system
(I) Routine function
● The bus control system has the function of memory and formula. When producing different products, the formulation of different products can be directly invoked. The formula contains parameters such as setting speed, height and so on. The formula call can be used to measure the thickness of the plate through the product thickness meter at the entrance of the production line, and then confirm that the data is saved to the corresponding formula, which can be invoked when the plate type is produced.
● With the whole line linkage, the one-key start and stop. The end terminal devices first when start, then sequentially start the front-end equipment one by one, and the shutdown sequence is just the opposite. This can avoid impact on the power grid if start all at the same time.
● When the fault occurs, the transmission equipment to the inlet of the fault machine should stop immediately, but the roller wheel will not stop, and it will rise to a safe height, keep the equipment running normally towards the outlet direction, and automatically drop to the set height after the failure reset. The fault types include conveying fault, plate stuck fault, dimmer fault, frequency converter fault, limit out-of-limit alarm and so on.
● When action linked, you can control any roll to run or do not run (disabled), and rise to a safe height.
● The UV dryer adopts electronic light source, which can adjust the light source steplessly. It can run in full power when there are plates, and also can adjust to 30% power when there is no plate standby. The power of the light source can be adjusted in real time.
● After fine-tuning the height of the on-the-spot rise and fall, this data can be transferred directly to the master control PLC to saved in the formula, the formula to preserve the memory, easy to call next time.
● A set of material detection device is installed at the entrance of the production line, which serves as the basis for system operation and standby state switching. This device also acts as an alarm signal for plate thickness detection, when the plate thickness exceeds the set thickness, It will send the I/O signal to the general control PLC to alarm and stop the transmission.
● Install a inspecting device on the dryer to determine whether or not the plate is stuck, stop immediately after the chuck, and avoid fire accidents.
● Due to the long production line, tricolor indicator lamp installed on each machine for better monitor the running status of the whole line, green operation, yellow standby, red fault.
● The functions of the background monitoring system include equipment running status monitoring, fault alarm information display, one-button start-up and shutdown functions, output statistics, formula setting and calling, user login and logout, and so on.
Figure 3 on-site production Lin
(II) Functional aspects of energy management
● Electronic dimmer is installed in the dryer of the system. The dimmer can adjust the frequency conversion speed of the cooling fan according to the power of the light source, so as to achieve the purpose of saving energy and reducing consumption.
● Each roll of rolling machine is equipped with paint weighing device and rubber wheel and steel wheel clearance adjustment device. The weighing device can monitor the paint weight in real time, and has the functions of upper limit stop oil feeding, lower limit refueling, upper limit alarm, lower limit alarm and so on.
● Besides, by adjusting the gap between the steel wheel and the rubber wheel, indirectly to determine the amount of paint, so as to convert the consumption of paint.
● Each device can be equipped with an intelligent meter, or install an intelligent meter throughout the line, to monitor the daily power consumption of each shift, thereby monitoring the electricity saving behavior.
● For the forward and backward roll equipment, the lifting height of the backward roller is automatically adjusted according to the position of the plate, this will ensure that the plate does not hit the roll when it enters the reverse roll.
● Because it will causes the paint to fall on the conveying belt when the roller is hit by the roller, which will affect the clearness and the maintenance of the devices, and the paint loss.
(III) Functional aspects of equipment maintenance
● The electronic dimmer has the running time record, when the UV lamp reaches its service life , the alarm prompts reminding replace the lamp tube, in order to carry on the equipment maintenance.
● Taking the solenoid valve of the oil feed roller as the timing basis, the usage time of each cots is judged, so as to remind the user when to change the rollers, so that the equipment can be better maintained.
● Haiwell cloud box (CBOX) / HMI has all the functions of Haiwell cloud platform. Through Haiwell cloud, this system can realize cloud monitoring and intelligent management, and support remote access control of mobile phone / computer Web. If the master control system is connected to the Internet, the remote monitoring function can be realized and the production data can be monitored and displayed in real time. Haiwell cloud platform has the function of cloud alarm. When the system generates an alarm, the alarm information can be pushed to the mobile phone APP, in real time to understand the operation status of the device, so as to deal with the equipment failure in time.
● Haiwell cloud box (CBOX) / HMI support MQTT data reporting function, can upload data to Mysql / SQL server and other mainstream databases, docking ERP/MES system, to achieve enterprise production information management.
● This system supports Haiwell cloud, Haiwell cloud platform built-in Haiwell cloud engine, cloud management functions. Through the Haiwell cloud engine, it can achieve remote PLC program download, monitoring, firmware upgrade and PLC diagnosis; Through Haiwell cloud management, remote upload and download of HMI/CBOX project, firmware upgrade and historical data export can be realized.
● Haiwell cloud platform, A / B key security access mechanism is adopted, the host and administrator manage the devices at the same time, and the audit mechanism is used to manage the access rights of remote visitors, at the same time, the length of visitors' access can be set. Make the access safer , more reliable.
● Haiwell PLC RS 485 communication supports different baud rates, different protocols, and different data formats at the same time. The communication program does not need to deal with the time sequence, which greatly saves the engineer's programming time. Especially to set scheduled frequency, operation frequency, running current or other signal processing to multiple inverters, it is very convenient.
● Ethernet PLC is selected to support multiple master machine to be accessed at the same time, and Ethernet port can also be used as master station to access other devices, as master or as slave, which is convenient for debugging.
● Haiwell large-screen display (TVBOX) can achieve electronic dashboard function, support 4-house, 6-house, 9-house multi-screens display, can display same local area network, multiple HMI/CBOX/IPC display on a large screen at the same time. It can also display a single HMI/CBOX/IPC interface, with a more economical solution can achieve the traditional electronic dashboard function.
Figure 4 Mobile APP Monitoring Interface
Figure 5 Communication program between master PLC and two stand-alone devices PLC through Haiwellbus
Figure 6 CBOX project development interface 1
Figure 7 CBOX project development interface 2