Application of frequency converter in the packagin

  • Detail

Application example of frequency converter in cigarette hard box packaging machine

I Overview

hard pack cigarette packaging machine is a highly automated production machine composed of more than 10000 parts

since the early 1990s, our company has produced an electrical control system with Mitsubishi PLC (FMR was used at the beginning) as the core for the only manufacturer designated by the National Tobacco Machinery Corporation, realizing the localization of the whole machine control

in recent ten years, with the continuous improvement of production technology, the sales of fragrant materials technology is expected to rise slightly in the fourth quarter of 2014. In order to meet the needs of the development of market economy, the host manufacturers have developed many new varieties and models while improving the machine performance. In addition to the common 20 cigarettes (7, 6 and 7 cigarettes in the box are arranged in three layers), double ten flat boxes, double eight flat boxes, high-speed models, etc. While the PLC control system flexibly adapts to these changes, it also applies the new technology and new performance to the developed products. For example, the display system that reflects the production process is changed from the original single-chip microcomputer analog display panel to color CRT display, and then developed to the current man-machine interface multi-function display. The communication function of PLC and advanced instructions are used to connect the upper computer PLC and the display into an organic whole. Therefore, the product is welcomed by users, especially operators. Hundreds of such packaging machines work on the production lines of dozens of large, medium and small cigarette factories across the country

II System introduction

1. system block diagram (Figure 2)

the control system is composed of PLC, frequency converter, man-machine interface, i/o interface, etc

2. the main process requirements of the machine tool for the control system are

1, the main motor starts smoothly, stepless speed regulation, and the running speed is packets/minute (about Hz). Inching speed Hz

2, the torque is increased at low speed, and the braking is fast

3, the machine tool can run for a long time, and it is required to be safe and reliable

4, the oil filling motor of the machine tool lubrication system automatically fills oil for 5 seconds every 2 hours (the time is adjustable) or manually

5, the electric heating wires (2*360w) on both sides of the drying drum are heated at constant temperature, and the control accuracy is 50 ± 0.05 degrees

6, when a fault occurs, it should be able to display the name and location of the fault

7. Unqualified products (cigarette packs) caused by various reasons should be accurately removed at the same designated station

8, the following conditions should be distinguished for the treatment of unqualified cigarette packs and shutdown faults

① when 15 faults such as low oil level, clutch overload and smoke squeezing occur, the machine must be shut down immediately

② unqualified products caused by cigarette short ends, lack of filter nozzles and other faults will not be stopped, only audible and visual alarm signals will be sent, and they will be eliminated at the designated station

③ unqualified products caused by aluminum paper leakage and lining leakage need to be shut down immediately, but they can be jogged and removed at the designated station

3. realization of the control scheme

when the workshop workers stack the 84mm long filter tip cigarettes in the cigarette warehouse and start the machine, the machine will produce the hard box cigarettes that are discharged according to certain rules through the process of controlling the temperature of molten steel in the furnace, removing impurities, adjusting components, etc. at the speed of

packets per minute, and then package the transparent paper and stick the golden pull wire. Although the production speed of the machine is very high and the process action requirements are complex, as long as we make full use of the characteristics of PLC and combine the production practice, we have developed a set of simple and thorough logic control scheme to fully meet all the process requirements

35 switch input signals and 10 switch output signals are used in the system. There are 9 kinds of basic instructions, 10 kinds of function instructions (such as Inc, MOV, BMOV, CMP, sftl, add, etc.), 8 timers, 6 counters, 8 pointers, 28 data registers (including power-off hold type), and a total of 1100 statements. The whole program not only realizes all process requirements, but also adds many auxiliary functions, such as statistical display of production time and downtime, statistics of fault frequency, statistics of finished product output and reject quantity, date and time display, generation and print output of daily production shift output report, etc. In addition, the operator is allowed to modify part of the operation data by using the touch switch on the man-machine interface

due to the high reliability, strong anti-interference ability and modification ability of PLC, the on-line commissioning and adjustment time of our control system is greatly shortened, almost eliminating the on-site service, and the general operators or maintenance electricians can be competent for the commissioning work. Therefore, it has been widely praised by the manufacturers

Figure 4: operation picture

4. operation experience and experience

① ingenious application of shift pointer command sftl:

cigarette packs have 20 stations on the machine to complete a series of packaging processes, of which the fault monitoring sensors of 7 unqualified cigarette packs are respectively distributed on stations 1, 2, 4, 7, 11, 13 and 17. We designate M100 to m119 memory areas as shift registers and use synchronous pulses as shift trigger signals, so that any one or more nonconforming products occurring in production can be sorted out at the same designated station when they occur at the same time. (see Figure 5 and 6 for program examples)

figure 5:sftl instruction and pointer application

Figure 6: eliminating dynamic display

② in order to meet the counting function of finished product output, we have designed a program with a maximum capacity of 100million packages. Based on the output of 120 bags per minute, two shifts of 16 hours per day and 30 days per month can accumulate the output for 2 years. This makes full use of the function of PLC data register. (see Figure 7 for the procedure)

III In 1996, the National Tobacco Corporation and Tianjin Tianjin Economic Commission firmly concluded that "the product fills the domestic gap and belongs to the advanced level of similar products in the country". In the same year, the unit passed the IS09002 system certification

this series of products has not only become the fist products of manufacturers for most of the utilization of high molecular polymers, but also created considerable economic and social benefits for the majority of users (cigarette factories) due to the high profits and taxes of the tobacco industry. In addition, this series of products are also exported to Hong Kong, Uganda, Vietnam, Tajikistan, Singapore and other countries and regions, generating a large amount of foreign exchange for the country

IV Future improvement direction

1. use rotary encoder, make full use of the high-speed counter function of PLC, and further simplify the program

2. add communication module to realize networking and facilitate user management

3. use FXGP software and FX2N-80MR to solve remote communication, realize network debugging and guide field operation. Set up a convenient and fast network bridge for technical exchanges between host manufacturers and users, and shorten the distance between regions. Further improve service efficiency and save costs. (end)

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