Application of the hottest Fieldbus in the polyest

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The application of Fieldbus in the post-processing combine machine of polyester staple yarn

I. preface

in the production process of chemical fiber polyester staple yarn, the post-processing drafting combine machine is the key equipment in the whole production line, and the control accuracy of each unit machine directly affects the quality of finished yarn. With the traditional mechanical long side shaft or synchronous regulator control, it is extremely inconvenient to adjust the process proportion multiple between each unit machine, and the control accuracy is difficult to ensure. Therefore, in order to facilitate the adjustment of process parameters and improve the control accuracy and reliability of the whole system, the control scheme of "Siemens TP170A touch screen +splc+ vector control inverter" is adopted

II. Introduction to PROFIBUS-DP Fieldbus

profibus is the fieldbus standard of German national standard din19245 and European standard en50170. PROFIBUS is widely used in manufacturing, process and building automation industries. PROFIBUS is divided into PROFIBUS-DP, profibus-fms and Profibus-PA according to the application characteristics. Its features are: PROFIBUS-DP (factory automation), fast plug and play; Profibus-fms (Universal Automation), universal, wide range of use, multi master communication; Profibus-PA (process automation), application-oriented, bus powered, intrinsically safe. PROFIBUS-DP is used for high-speed data transmission at the device level. The central controller communicates with decentralized field devices through high-speed serial lines. Most data exchanges are periodic. In addition, intelligent field devices also need non periodic communication for configuration diagnosis and alarm processing

profibus protocol can be realized through the combination of PROFIBUS special protocol chip and microprocessor. In the field of power transmission, each company has launched its own communication template to realize PROFIBUS protocol, which can be directly inserted into the frequency converter to complete communication. For example, the CBP board in Siemens SIMOVERT mas-terdrivers frequency converter and the tds-pa01 adapter of Emerson frequency converter. This paper describes the specific application of PROFIBUS in the transmission system of polyester staple post-processing drafting combine

III. application of PROFIBUS Fieldbus in polyester staple fiber post-processing drafting machine

1. Introduction to the transmission system of polyester staple fiber post-processing drafting machine

taking the transmission system of polyester staple fiber post-processing drafting machine as an example, this paper introduces the application of Fieldbus in the drafting machine system

the chemical fiber polyester bottle sheet is wound by melt spinning and oiled to form a tow, which is fed into the silk bucket. The tow in the silk bucket is led out from the bundle rack, oiled through the oil immersion tank, and enters the first drafting machine; There are two drafts in this production line. One draft is carried out between the first draft machine and the second draft machine; The drawing temperature required for one drawing is 75 ~ 80 ℃, which is provided by the water bath drawing tank. The second drafting is carried out in the steam drafting box between the second drafting machine and the third drafting machine, and the drafting temperature is about 95 ~ 100 ℃; The drawn tow is folded into a piece by the silk stacker and sent to the crimping machine to curl the tow. The system structure is shown in Figure 1

the system uses six sets of Siemens vector controlled inverters to drive six unit machines respectively. PLC adopts Siemens s series. The PLC master station is set in the main control cabinet, and the Siemens TP170A touch screen is installed on the field console. The touch screen and each frequency converter are slave stations. PLC connects the master station and slave station through PROFIBUS-DP Fieldbus to form an industrial fieldbus system, which not only improves the reliability and high performance ratio of the system, but also greatly facilitates the technicians and operators. The system mainly has the following features and new functions: ① vector control frequency conversion technology, the encoder and inverter on the motor form a speed closed loop; ② With energy consumption braking and mechanical braking, the braking work is automatically put into operation when parking, which is reliable and stable, realizing rapid parking at high speed; ③ Advanced industrial fieldbus system and PROFIBUS bus; ④ The touch screen makes it easy for users to operate, real-time display of speed, current and other data, monitoring and display of electrical system operation, fault display, diagnosis, alarm, etc

2.profibus-dp network table 12 composition of experimental items, cycles and requirements of safety belts

a single master PROFIBUS-DP communication system is formed by using s cpu313c-2dp as the master station, inverter plus CBP board and field touch screen (TP170A) as the slave station. DP is suitable for field integration of high-speed data communication. It adopts RS-485 twisted pair cable or optical fiber cable. The baud rate is from 9.6kbps to 12mbps. It adopts point-to-point (user data and transmission) or broadcast (control instruction) mode, and supports cyclic master-slave data transmission. The composition diagram of Profibus network is shown in Figure 2

since the PLC master station and all slave stations are products of Siemens, they all meet the Profibus bus communication protocol. In this system, RS485 shielded twisted pair is used as the communication medium, and the communication baud rate is 1.5mbps, which is a PROFIBUS ring network. PROFIBUS-DP mainly uses the master-slave mode, and the PLC master station periodically exchanges data with the transmission device. In the Profibus structure, the available data of the periodic channel mscy-c1 is defined as the parameter process object PPO, and the available data structure is divided into two different parts and transmitted with messages mainly applicable to plastic plates, pipes and profiled materials: PZD part (including control word, set value, status word and actual value); PKW (for reading and writing parameter values). When the bus system is started, this type of PPO for the displacement accuracy up to 0.001mmprofibus master station to the transmission device can be set. The setting of that type of PPO depends on the function of the transmission device in the automatic network

profibus devices have various characteristics. In order for all master station systems to correctly call the additional boards used, the master data file GSD of each device must be required. In order to communicate effectively, in STEP7, the address must be set for each bus device to address the master station. The communication parameters set on the CBP board are: p918 (bus address), p712 (PPO type), p722 (message failure time of process data)

the system adopts PROFIBUS-DP bus, which saves a lot of cables to the machine, increases reliability, reduces the interference of the frequency conversion system, and is convenient for personnel operation and maintenance

3. Diagnostic function of PROFIBUS

profibus has a powerful diagnostic function. When receiving an alarm or error transmitted from the slave station, the master station will quickly respond, suspend normal communication, and quickly locate the fault. This diagnostic information is divided into three levels: local station diagnostic operation, module diagnostic operation and on-off diagnostic operation. After the fault is cleared, the bus resumes normal communication

IV. prospects and advantages of Fieldbus Technology in power transmission system

power transmission is an important branch of industrial automation. With the development of power electronics, microelectronics and computer technology, power control devices have a considerable level of autonomy and intelligence. The application of Fieldbus Technology in the field of electric drive has the following advantages:

① promote the full digitalization of electric drive. Due to the development of fieldbus system, information exchange can be realized between devices from different manufacturers. Users can form a system of arbitrary size according to their own needs and considerations. So that manufacturers will further increase the full digitalization of devices when applying fieldbus technology to products

② reduce the installation cost and maintenance cost of electric drive control system. Because the intelligent devices scattered in the field in the fieldbus system can directly perform a variety of sensing, control, alarm and calculation functions, the number of transmitters can be reduced, so as to reduce the system hardware investment. Moreover, the wiring of the fieldbus system is very simple, and the consumption of cables, terminals, slots and bridges is greatly reduced, saving the installation cost. Since the field control equipment has the ability of self diagnosis and processing simple faults, and sends the relevant diagnosis and maintenance information to the control room through digital communication, the user can query the operation and diagnosis and maintenance information of all equipment, so as to analyze the cause of the fault early and remove it quickly

③ make full use of software functions to improve the ability of complex control of the system. Because of the intellectualization and digitalization of fieldbus system equipment, compared with analog signals, it fundamentally improves the accuracy of measurement and control; Transmission error is reduced. At the same time, due to the simple structure of the system, the round-trip transmission of signals is reduced and the reliability of the system is improved. The direct input and output cable connection between PLC and transmission device is reduced, and the software function is fully applied. All control quantities are realized through fieldbus, which improves the complex control ability of the system

v. conclusion

production practice has proved that this scheme has the characteristics of simple and practical, stable and reliable operation, convenient operation and maintenance, and has been successfully applied to the chemical fiber polyester staple post-treatment drafting machine, and has achieved good economic and social benefits. (end)

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