(I) Extremely unique control system
In the manufacturing process of ultra-fine fibers, the extractor is a key equipment with high explosion-proof requirements, small transmission tension and strict synchronization requirements. To meet this need, we have adopted a series of new technologies and created a unique set of control systems. It is summarized as follows:
1) Application Software Development of PLC
This is the core technology of system development. We use a large number of data operation instructions instead of contact commands in PLC software, which greatly improves programming efficiency and saves space. At the same time, a large number of high-level programming languages such as FOR-NEXT loop and V, Z index modification, CALL calling subroutines, and STL sequence statements are used, which greatly improves the standardization, readability, and easy checking of software design.
2) The function of the frequency converter is fully developed
We have selected Fuji E11S inverters manufactured in Japan for the 31 motor synchronous control, using this inverter with many functions and giving full play to the role of more than 200 software functions for each inverter. For example, the motor soft characteristics that are useful for synchronous control, the torque limit function, the second acceleration, and the second frequency setting all play an important role in our system.
3) Image software development and design excellence
As the operator's most direct contact with the computer monitor screen, we extensively listened to opinions and suggestions from various parties at the site and conducted a large number of meticulous design changes. This image software not only meets the needs of operators, but also adds a lot of production statistics. The cloth ratio data exceeds alarms, automatic removal of guides, and other practical functions are highly praised by managers.
3) Full coordination between PLC and inverter, SCD
This is the key to obtaining extremely excellent control quality. The SCD synchronous controller is only put into use after the vehicle speed is stable, and the SCD control must be removed after the steps such as the flexible jogging method and the start-up speed reduction of the drive. After careful debugging, these transitional processes have been smoothly controlled.
(II) Main Indicators of Outstanding Control Quality
1) The tension signal is always stable in the middle zero position under any working condition (deviation < 5 %)
• The tension is stable regardless of whether it is a microfiber cloth or a guide cloth or a thick cloth guide.
• The entire process of driving and speeding up and down must be stable.
• After parking, it is also required to be stable and will not falter.
2) The process of transition to SCD control is stable without obvious disturbance, and it is in line with the 1/4 attenuation curve method.
3) The torque is limited. When an abnormality occurs, it will not pull off the cloth. When the axis is pulled and bent, the motor will not be burned when the rotation is blocked, so that it is not hard to pull when pulling.
4) The inverter and each motor have a good matching state, save power, and have a large output. When the inverter is stalled, it does not exceed the current, it is not easy to trip, and no fault occurs. Achieve true "tailored" of inverter and motor.
The above articles are fully reflected in our system.
(c) Technical analysis of synchronous control
1) Analysis of motor characteristic curve
In order to facilitate the synchronization and to prevent breaking the Brad bending roller in the synchronous control, it is particularly useful to set the soft characteristic of the motor. The microfiber cloth has about 7 % of tension in the drawing process, so it is necessary that the speed of the motor be properly improved from front to back. Motor characteristics will become increasingly soft from front to back. Both of these can be changed through the parameters of Fuji Converter. Change the parameters of each inverter in the case of on-site driving, so as to obtain a more ideal control effect.
2) Technical analysis of motor soft characteristics to help synchronize implementation
In Figure 1, the tension roller W9 is used to control the principle of the down-stage motor M9. When the cloth is released, the tension roller moves upwards and the displacement signal is accelerated by the SCD control M9 to make it tight.
The effect of these two feedback adjustments is consistent and common, and the latter adjustment is faster, but the adjustment is more limited. This method of synchronizing by the soft characteristics of the motor alone can be used in situations where it is difficult to install a tension signal roller, such as a dry process line. Used in this system is to strengthen the synchronization, is conducive to the stability of the synchronization control.
4) Some experience
1) Choose and use hardware such as inverter
Why choose Fuji E11S inverter? It is true that I personally acted as a technical support engineer in Fujifilm for one or two years. I am very familiar with Fujitsu's inverter. However, the more important features of the inverters mentioned above are none other than the non-Fuji brands. Each of our drives for transmission has as many as 16 signal lines. Including forward rotation, reverse rotation, RT1 second acceleration, acceleration, deceleration, second frequency setting, 30A alarm, pre-overload alarm, RUN signal, FMA frequency signal, 10V voltage input and other 12 kinds of input and output signals. In contrast, Mitsubishi inverters used by another company for synchronization have only 6 signal lines, forward rotation, 10V voltage input, RUN signal and other 3 signals (see Appendix 1), 12:3. Fujitsu's various functions make it truly play its due role.
2) Any good design cannot be done in the design room but only on site.
Tailored clothes must go to the scene. According to the actual situation, they can be measured accurately and tailored properly. The motor parameter auto-tuning function of the inverter is to obtain the best matching parameters of the inverter through on-site automatic testing of the impedance impedance of the motor and other parameters. Designers do not do the job well at the scene. Our system design, more than 50% through repeated modification and modification on site, can reach this level today. We would like to thank the company's leaders for their efforts to provide us with a better living and working environment under very difficult conditions. We have successfully completed all kinds of debugging and design tasks. At the same time, we would like to thank Wang Gong Sun Gong and the workshop leaders and workers for their attention and solutions and provide all kinds of help.
3) To be truly user-oriented and user-oriented as the first goal.
Really change the idea of afraid of reform programs. The first goal of the user's needs is also a transition process. For example, the user proposed to increase the reversing function. At first, I disagreed. Later I saw that during the trial process, a dozen workers slightly moved the guide from the back to the back. Drag before, in order to make the cloth of the middle drag roller loosen. This scene prompted me to immediately come up with a solution that quickly and well resolved any plan to achieve reversing the motor.
Gao Ziyi, Senior Engineer
September 24, 2004 in Wenzhou