Industrial automatic control and control of the cheeks and the (state of the key electrical appliances in the cement i production ten used Tangshan Jidong Cement Co., Ltd. (063031) Shen Shuo Bo Lizhi Li Guangyu 1 cement packaging machine work characteristics and environmental conditions cement packaging machine The environment is dusty, and the electrical components are filled with cement powder. It is easy to make contact failures such as relays, contactors, and limit switches, and often malfunctions such as malfunction, refusal, and difficulty in starting. Sometimes, in order to improve the operation rate, multiple groups are touched. The point is used in parallel, but this does not solve the problem fundamentally. It is not that the impeller motor does not operate, or the electromagnet does not operate, which seriously affects the normal production.

Relays, contactors, limit switches, etc. on an 8-mouth rotary packaging machine operate 6,000 times a day. The service life of the better quality relays and contactors is 200,000 times. Thus, the service life of the relays and contactors on the cement packaging machine is only 33 days.

Due to the influence of dust, these relays and contactors can no longer be used in about 20 days, and even faults such as poor contact within 20 days are frequent.

In order to change this situation, after careful analysis and research on the electrical control system of the cement packaging machine, the Siemens logic control module LOGO and the non-contact technology solid state relay were used to develop a set of electrical control suitable for the working environment and characteristics of the cement packaging machine. system.

2 cement packaging machine electrical control system 2.1 solid state relay performance characteristics state electronic components composed of non-contact switching components. Its characteristics are small size, fast switching speed, no mechanical contact, no mechanical wear and mechanical noise, vibration and shock resistance, no fear of dust and corrosive gas, long service life, no sparks and arcs during on-off, and low interference. In addition, the solid state relay has a low driving voltage (generally 3.2~32V), a small driving current (generally 5~40mA), and is easy to interface with a computer. Therefore, the solid state relay is more and more widely used as an automatic control execution component. It is especially suitable for places with large environmental dust and frequent starting.

2.2 Logic Control Module LOGO Introduction LOGO is the latest logic control module developed by Siemens. It is small in size, low in cost, fully functional, and compact in design, providing a complete solution for a variety of simple practical applications. There is a display unit and an operation unit on the panel, which can directly perform programming, parameter setting, program modification and other operations on the LOGO. The internal program is displayed through the display unit and can be connected to the network through the RSI bus. It is also possible to quickly write and debug the user program on the computer, and then install the user program through the cable. The logic control module LOGO is programmed with function blocks, such as AND gate, OR gate, NOT gate, NAND gate, NOR gate, etc. 6 13 kinds of special functions such as basic functions and time relay, RS trigger, counter, pulse generator and frequency generator. It is easy to realize the processing of input information and the control of output function through function block programming. LOGO's application reduces external components, wiring is simple, and reliability is increased. Changing the control circuit function only requires modifying the internal program, reducing the workload, saving time and increasing work efficiency.

2.3 The working principle of the system is the schematic diagram of the electrical control of the cement packaging machine developed by Siemens logic control module LOGO and solid state relay.

The 1SSR is a three-phase AC solid state relay used to control the impeller motor. The 2SSR and 3SSR are single-phase AC solid-state relays that control the gate pick-up electromagnet and the off-bag electromagnet. 1SSR, 2SSR, 3SSR are AC zero-crossing solid-state relays. Regardless of the phase of the applied control signal, the output of the solid-state relay always starts to conduct when the AC power supply voltage crosses zero, and the RF interference generated during conduction is small. In order to protect the 71994-2015 industrial automatic control model control Yang in the cement transfer to the furnace control system, Zhejiang University Electrical Department (310027) Yao Weizhen Zhu Jing introduced the fuzzy control technology in the cement rotary kiln decomposition furnace temperature control Successful application and analysis of the overall structure and application software development of the DCS system in the production process of cement rotary kiln. The actual operation results show that the system is stable and reliable, and the control effect is good, which meets the requirements of the production process.

1 Introduction The cement production process is a physical and chemical reaction process with large inertia, pure lag, nonlinearity, etc. The system conditions are complex and variable, and it is difficult to establish accurate mathematical models. Therefore, it is difficult to obtain satisfactory control using traditional control strategies. effect. In order to achieve stable operation process, optimize technical parameters, save energy and reduce consumption, and improve the operation rate, the world's major cement manufacturers and computer companies have not only paid attention to the application of DCS system in cement production lines, but also developed some applications for cement production. Advanced control strategies for all major aspects of the process, including fuzzy control technology, have played a significant role in improving production and quality, energy saving and stable working conditions.

Fuzzy control is a combination of fuzzy mathematics and control theory. It can solve the control problems of many complex systems that cannot establish accurate object models. It is an effective method to deal with inaccuracies and uncertainties in control systems.

The solid state relay is reliable for long-term operation. The starting current of the load should be within the rated current range of the solid state relay. The model of the impeller motor is Y112M-4, the rated power is 4WV, the rated current is 8.8A. The general starting current is about 6 times the rated current. The 1SSR should use the solid state relay with the rated current not lower than 52.8A. The higher the temperature, the higher the work is allowed. The smaller the current, the solid state relay should be mounted on the heat sink when the current is greater than 15A.

1RV2, 2RV, and 3RV are varistor. In order to prevent the impact and interference of the peak surge voltage from the power supply to the solid state relay, the absorption circuit should be connected in parallel with the output of the solid state relay. The absorption circuit is generally an RC series circuit, a varistor, or both. The RC series sink circuit is typically packaged in the housing of the product. The new dry process cement production line of varistor Hangzhou Cement Plant with an annual output of 300,000 tons of high-grade cement uses the PlantScapeDCS system introduced by Honeywell to realize the fuzzy control of the temperature of the rotary kiln decomposition furnace, and the real-time monitoring and analysis of the cement production process. optimization.

2 Fuzzy control of decomposition furnace temperature The new dry process cement production line of Hangzhou Cement Plant adopts the widely used “preheating decomposition of five-stage cyclone kiln” technology, and the whole production process includes preheating decomposition outside the kiln. Calcination in the kiln, clinker cooling, waste gas treatment and pulverized coal preparation.

In the rotary kiln cement production process, the kiln tail decomposition furnace temperature is an important process parameter, and the stability of the decomposition furnace temperature has a significant impact on the stable production, high production and energy saving of the entire cement production line. Based on the analysis of the production process and on-site sampling data and the experience of the operators, it can be found that if the speed of the coal-slip motor is increased, it is a kind of non-linear resistor, which is equivalent to a high-voltage bidirectional voltage regulator. The nominal voltage of the varistor is typically 1.9 times the supply voltage.

The PD is a DC power supply that provides operating and control power to logic control modules and solid state relays.

1FU2, 1FU3, 2FU, 3FU are fast-acting fuses for short-circuit protection of solid state relays.

The 1SA is the discharge nozzle proximity switch, the 2SA is the start proximity switch, the 3SA is the weighing proximity switch, and the 4SA is the off-bag proximity switch.

The LOGO logic control module uses a transistor output type to ensure contactless control and extend the life of the control system. The output current of each output is 300raA, which can fully meet the pulverized coal flow rate of the solid state relay control electric power into the decomposing furnace, which aggravates the reaction in the decomposing furnace and raises the furnace temperature. The higher the speed, the faster the temperature rises.

If the speed of the raw slip motor is increased, that is, the flow rate of the raw material of the human kiln is increased, and the amount of the reaction material in the decomposition furnace is increased, the temperature of the decomposition furnace is increased. However, after increasing to a certain extent, the temperature of the decomposition furnace decreases due to insufficient reaction of the material. In fact, a certain proportional relationship should be maintained between the raw material flow rate of the human kiln and the pulverized coal flow rate of the human decomposition furnace in order to carry out a sufficient reaction.

If the rotary kiln rotation speed is increased, the temperature of the decomposition furnace slightly decreases, but the relationship between the two is not very obvious. Under normal conditions, the rotary kiln speed remains basically the same.

From the above analysis, it can be seen that the rotational speed of the coal-slip motor is a major factor affecting the temperature of the decomposition furnace. The rotational speed of the raw slip motor and the rotational speed of the rotary kiln also have a certain influence on the temperature of the decomposition furnace. The flow rate is 4~50mA. Claim. L+ and M are the work of LOGO, which control the solid state relays 1SSR, 2SSR, 3SSR and impeller motor working indicators.

3 Conclusion The electrical control system of cement packaging machine using logic control module and solid state relay was put into operation in Tangshan Jidong Cement Co., Ltd. in July 1999. Since the operation, there have never been any malfunctions such as misoperation, refusal, and difficulty in starting, and the ordinary relay has been completely solved. The contactor has a high failure rate, low reliability and short service life in a place with large dust and frequent starting, which effectively ensures the normal operation of cement production. (Series: Luo Yi)

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