Application of the hottest PLC in flat screen prin

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Application of PLC in flat printing drying room system

1 Overview

with the continuous improvement of people's living standards, people have higher and higher requirements for fabric patterns and colors, among which the drying room system is a very important link

the drying room system is an important part of the flat (cloth) printing machine. It receives the printed cloth sent by the printing machine and carries out drying and shaping treatment in the drying room. In this process, the key is to control the speed of feeding cloth, otherwise the printed pattern will turn into flower, which will seriously affect the printing quality. Under the perfect combination of Twido PLC, variable frequency converter, sensor, etc., the product quality and speed of the whole system have been greatly improved (Guide avoid using solid tools to stop the clearing belt, and the speed can be up to 36 meters/second)

2. System composition and control requirements

the main composition of the system is:

1) Twido PLC module: twdlcma20dra and i/o expansion module

2) xbtg2220 color touch screen

3) atv38 and ATV58 frequency converters

the control system can be divided into the following parts according to the process function: air induction part, circulating air part, cloth inlet and outlet part, deviation correction and temperature control part, which are described as follows:

a. air induction part: bring the excess heat in the drying room out of the room It is the part of the system that starts up first

b. circulating air: it can only be started after the induced air is turned on. Through the circulating air in the drying room, the temperature in the drying room is kept consistent. The air volume can be adjusted manually or automatically according to the requirements of the whole system (6 atv38 frequency converters are used)

c. incoming/outgoing part: it is the core part of the system. Accept the "synchronization" signal from the printing host, and adjust the acceleration and deceleration through the photoelectric switch to make the system speed consistent with the printing host speed. When the speed of the printing host is greater than the speed of the feeding motor, the buffer storage area will buffer it first. If the accelerating photoelectric switch is encountered, the speed of the feeding motor will increase to make its speed balance with the printing host. On the contrary, when encountering the deceleration or stop photoelectric switch, the cloth feeding motor pauses to wait for the host signal. If there is a signal, the cloth feeding motor follows the action; For the cloth feeding motor, the speed also comes from the sales volume and sales volume, which has completed the "synchronous" speed of the large climb printing host. At the same time, it is equipped with a tension bar and a limit switch for automatic control. When the cloth feeding speed is within the activity range of the tension bar, the tightness of the cloth is controlled by the weight of the tension bar, and the cloth feeding speed remains unchanged, If the feeding speed exceeds the activity range of the tension bar (greater or less), accelerate or decelerate the feeding motor through the photoelectric switch to maintain the consistency with the feeding motor speed. When the printing machine is suspended, the wind speed of the circulating fan decreases, and the cloth guide belt swings back and forth to prevent the cloth from being burnt for a long time in the drying room. (use atv58f frequency conversion)

d. deviation correction and temperature control: deviation correction and temperature control are operated at the same time as the above operations. Deviation correction is used to correct the deviation of the guide belt of the cloth feeding motor. Due to the non-stop circular operation of the guide belt, it may deviate at any time, and it is automatically adjusted by photoelectric switch and limit switch. The temperature is set and controlled differently according to different fabrics (cotton cloth, blanket, thickness, etc.)

the start-up of the system and the start-up and stop of the induced draft fan and circulating fan are controlled by the touch screen. Similarly, the speed of the acceleration and deceleration of the cloth inlet/outlet and the deviation correction time interval are set by the touch screen; At the same time, alarm records are set for easy inquiry at any time

3. At the end, the collected pages are analyzed by the analysis index system program.

the system with Twido PLC and touch screen as the control center has the following characteristics:

1) the cloth inlet storage buffer is set up in the Twido PLC program, which improves the cloth inlet speed and makes the system work more continuous and high-speed; Twido PLC has double word and floating-point operation, which greatly improves the feeding accuracy

2) the use of touch screen greatly reduces the number of external buttons, that is, saves a lot of Di, so the use of touch screen does not bring significant cost increase. In addition, the touch screen is flexible and convenient to operate, and the system information can be monitored in real time, which enhances the operability of the system

3) the Twido PLC system has fast dynamic response, which can quickly respond to the feeding speed set by the system (0 to 36 m/s), thus significantly improving the stability of the whole system

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