Development On The Control System Of Circular Storage With Stacker And Reclaimer Based On The PLC

Circular stacker reclaimer is the key part to finish coal storing and conveying in coal handling system of thermal power plant. Compared with conventional open stockyard, the main advantage of circular stacker reclaimer is no pollution produced to ambient surroundings owing to it's operation in closed as well energy conservation, less coverage, uniform mixture, high adaptive capacity to environment, high efficiency (simultaneously alternative operation of stacking and reclaiming )and high automation.But the start of the circular stacker reclaimer was put in operation in China very late and the engineering cost is higher due to importing whole machine. However owing to it's advantages, the demand on this machine increased yearly, and the potential market is quite big. With the execution of national policy"increasing bigger and reducing smaller"for the construction of power plants, also the tendency of developing clean energy, at a certain period I the future, China will be of an important market of circular stacker reclaimer. It is the only way for the construction of circular stacker reclaimer project in China that first introducing updated technology from overseas countries and then developing our own.The circular stacker reclaimer has the features of complicate operation flow, more check loops and safety and reliability, thus higher requirement has to be considered for its control system. Focusing on PLC control system as well adopting industrial PCs and field bus and so on are also the requirement on control flow of this machine.The application of distributed control system is the landmark during the developing of process automatic control technology. It has been the mainstream of the development of process automatic control worldwide. To understand this system, to study this system and to use this system have been the research direction at industrial control field. It is very important of application of the distributed control system for circular stacker reclaimer.The PLC control system of circular stacker reclaimer consists of Rockwell ControlLogix hardware and RSLogix5000 software package. The redundancy design of PLC and bus linking with PLC of field switches limit and sensors improve the reliability of the circular stacker reclaimer. The rough condition on job site is easy to disturb the operation of PLC and cause error code, error operation and even system failure and breakdown. In order to reduce such impact on PLC, a lot of measures of anti-interference are used for hardware as well digital filtering is used for field sensors, etc, other software. The application of module design, modular organization and fault-tolerant design( program roll-back and instruction retry) improve the reliability of software.The stacking mode and reclaiming mode are respectively relative to stacking operation and reclaiming operation for circular stacker reclaimer. The above-mentioned stacking and reclaiming modes can realize the effective and cyclical utilization of space in circular stockyard. At the same time, during stacking and reclaiming, the coal at a definite rate will be blended to increase the degree of pre-mixture and combustibility of coal to guarantee the constant generating capacity of power plant. The function of automatic operation and overall fault prompting and data statement bring more convenient for the operator at remote control room and facility management.In addition, the secondary system of circular stacker reclaimer, including ITV, laser automatic scanning and measuring has an important assistant effect on improving automation and unmanned operation of the machine. According to commissioning and trial run of circular stacker reclaimer on job site, based on test data and trial operation results, a conclusion can be drawn that the machine was in conformity with design requirement and the control system met the demand on operation flow. All this are highly evaluated and accepted by clients.