1 Introduction In recent years, with the improvement of our automation technology, factory automation is also on a new level. As an emerging industrial PLC controller, with its small size, full-featured, low cost and high reliability has unique advantages, in various fields has been applied widely.
As the largest printing press manufacturer --- North people group, in order to make the product performance is stable, easy to maintain, we have adopted a PLC-based controller to control the program. As the two-color printing requirements and easy to operate, high precision, so the input and output points more, so a dual-machine communication. PC with Mitsubishi FX2N-80MR 32EX 4D / A, is mainly responsible for the control of the main transmission, the clutch pressure control unit, as well as pump, valve control. Lower machine using Mitsubishi FX2N-64MR 4A / D, is mainly responsible for water roller motor control, the main drive of the speed output, adjusted version of electrical data acquisition. Mitsubishi also selected a 5.7-inch touch screen, is responsible for water roller motor speed display, transfer version display and display machine faults. The system is reliable, easy maintenance, simple operation, greatly increased the grade offset by users.
2 System Structure The system structure is as follows:
Among them, the upper computer and lower computer using RS485 communications, communications convenient and reliable. On the multi-color machine, the security factor is very important. In Sheji in each unit not only to consider the safety control, including standard emergency stop unit, safety button; also consider convenient operation, including each unit shall have the punctuality, anti Dianan Niu. Therefore, on the one hand increase the number of input points; the other hand, the alignment is also very convenient. Dual-machine communication, can solve this problem, the alignment of the various units can follow the principle of proximity, access control from its close cabinet, saving the alignment, but also easy to control.
As the printer is a high precision machinery, printing is good or bad one is the precision machining and installation, on the other hand, it depends on the water, ink balance and accuracy of joint pressure. Each color group color machine, has water and ink device. In order to facilitate the regulation of water roller speeds, the water of each roller are controlled by a frequency converter, while the main motor speed regulation also requires converter. Therefore, in order to achieve multi-speed adjustment, we used Mitsubishi 4D / A DAC, it will give the digital PLC side, according to the corresponding algorithm, converted into 0 ~ 10V DC voltage output, is very well for Multi speed adjustment requirements.
In the printing process, transfer version is a more complicated process. Especially for multi-color machine, the version of each group will be printed on the accuracy of product is a large impact. If the overlay are not allowed, there will be literally printed images overlap or confusion. In general, the plate axial adjustment range is-2mm ~ 2mm, weeks to adjust the range of-1mm ~ 1mm. If you use the manual tune version, will waste a lot of time, and accuracy is not high. In order to achieve automatic making, we have installed in the version of roller potentiometer, via potentiometer to analog transmission to 4A / D, through the PLC, may be a good precision of drum rotation control in the play version of range.
As a new touch screen user interface, there would be concern from its easy to use, powerful features and excellent stability make it well suited for industrial environments. Users can freely mix text, buttons, graphics, figures and to deal with or monitor the management of information is subject to change. With the rapid development of machinery and equipment, the previous interface required by a skilled operator to operate, can not improve efficiency. But the use of man-machine interface, can clear instructions and tell the operator the current status of equipment, make the operation simple and vivid. Use the touch screen, you can also make the machine wiring standardized, simplified, while also reducing the required PLC control I / O points, lower production costs, also enhanced the value-added package of equipment. Mitsubishi Mitsubishi PLC touch screen and good versatility, able to monitor and modify the program online, do not repeat the plug is cumbersome interfaces.
3 Software Design
3.1 to the paper, the overall design of the electrical design or printing more complex, time requirements are strict. In many parts of the machine is equipped with proximity switches, used to detect different time points. In the printing process, take the paper s good or bad is the impact of the quality of an important part of the machine. The quality of the so-called paper away, that is not distorted Zhang, double sheets and other phenomena, if the distortion of sheets, the phenomenon of double sheets, high-speed cases, you will take the bad paper, the involvement of the machine, thus undermining the rubber, great loss to the user. This process flow is as follows:
In the experiment, we found that, in accordance with the procedures for the preparation of the above-mentioned processes, there is no problem at low speed, but the speed increased to 7000r / h, the phenomenon appears distorted Suobu Zhu Zhang. The reason is mainly because the skinhead movement reaction time and the time lag caused by the magnet. Procedures in the implementation process, using cyclic scan mode, in order to advance solenoid output in the design, I used the Mitsubishi programming instruction interrupt and the input and output refresh command to the immediate implementation of the output solenoid, electromagnet moves ahead of time, Even in 12000r / h speeds, but also a very good lock faulty paper addresses a major problem to the paper.
3.2 clutch design from the pressure, combined with pressure in the printing of a very important role. Clutch the accuracy of the printing quality is good or bad has a direct impact. Combined pressure of premature and might damage embossing roller toAction caused much inconvenience; from the pressure early, do not make the final printed piece of paper on the complete pattern, resulting in waste of paper.
In the design, from the pressure, combined pressure of the process flow as shown:
Print, the version with the rubber roller roller-before-pressure rubber roller and impression roller pressure after the joint. In our machine, all combined with a pneumatic pressure device, each cylinder has an action time. As the printing speed multi-speed, in the 3000 ~ 12000r / h between the needs of the user can choose different speeds. However, the action time is certain cylinder, gear turn angle is certain, therefore, the machine speed is not the same time, combined pressure of time is different. To solve this problem, we calculated the value based identify different machine speed, machine delay time. With more instructions, when the machine-speed is equal to the theoretical value, the corresponding time delay, so that embossing roller and rubber roller accurate joint pressure. After several tests, from the pressure, combined with pressure no problem.
3.3 man-machine interface design in human-computer interface, designed seven pictures, including the overall graph, fault indication, the machine speed and count showed that the water roller speed display, accent version monitoring. Fault that the use of indicators, components can be realized given bit flash effect, allows the operator to know the fault location is very convenient, the overall sense of well. Roller speed in the water show, the design of a histogram, you can increase the size of the water show, just press the histogram, you can increase the amount of water, but also can be easily monitored. As shown:
4. Conclusion electrical design of a printing press belonging to system design, including hardware, software design, covers a wider scope. Here, I will only highlight the more important parts of them, there are many other details, I will not list them. Mitsubishi set to use control system, feel reliable, convenient mass production process of the machine and found no major problems. The PLC fully functional, durable and reliable, simple instructions, and other products than the overall software interface, Mitsubishi feel are more friendly to the user programming, maintenance is a great convenience. The touch screen and PLC have good versatility, can touch screen] to monitor and modify the program, which is other products can not match and the. In short, the Mitsubishi industrial components to designers and users have brought a lot of convenience.