外文翻译---plc在蒸汽锅炉汽包液位pid控制系统的应用分析-plc设计(编辑修改稿)

外文翻译---plc在蒸汽锅炉汽包液位pid控制系统的应用分析-plc设计(编辑修改稿)内容摘要：

conforms to the correspondence, stops to the water valve in some position. If has or many signals changes, the state of equilibrium is destroyed, the PI adjustment module output will certainly to change. When the water level elevated, then the adjustment module output signal reduces, causes to close slightly for the water regulating valve. Otherwise, when the water level reduces, the adjustment module output value increases, causes to open in a big way to the water valve. The practice proved three impulses can maintain the water level for the water single pole regulator system stably, also gives the water regulating valve movement to be steady. The boiler also has a quite important control loop for the aqueous system in is for the hydraulic pressure return route, because the steam drum internal pressure is higher, must make up the water to the boiler to have to provide a higher pressure, enhances the hydraulic pressure for the hydraulic pressure return route function, enables the water normally to pour into the steam drum. But in the steam current capacity had not achieved when full load, to gives the water current capacity the request not to be high. Generally uses the feed pump in the old style boiler system continuously by the labor frequency way revolution, reduces the hydraulic pressure with the return valve to prevent the cartridge igniter, now generally uses through the frequency changer constant pressure water supply way control hydraulic pressure. Boiler to water volume through steam drum fluid position adjustment. The steam drum fluid position survey selects floats the tube liquidometer. For the effective use transformation waste heat, reduces the consumption, decreases the labor intensity, is advantageous is stable to the overall craft, requests the steam drum fluid position automatic control, when regular production the undulation should be smaller than 177。 5%. The PID adjustment steam outlet valve may the very good control dome pressure. After drives normally undulates the scope not to be big, may not consider. The transformed load undulation, the preheater boiler for the water temperature change, the boiler load undulation, dumps pollutants the quantitative change these factors to have to consider to the steam drum fluid position influence. Take the steam drum fluid position as the main tuning parameter, take gives the water current capacity as the vice accent parameter, take the steam current capacity as a forward feed, but the adjustment effect is very bad. Causes the steam drum fluid position major rises and falls. Considered this waste heat boiler controlled variable coupling small, flow simple, produces the steam quantity to be also stabler, we are inspired from in operator39。 s operation, thinks the reduction thus to stabilize to the water volume undulation to the water temperature bees this waste heat boiler fluid position control the main point. Therefore we select to the steam decide the water + fluid position forward feed the ratio control plan, plan diagram like chart 3 shows. Chart 3 the steam decides the water + fluid position forward feed ratio control plan diagram Coefficient K is the soft drink loss factor (gives water current capacity and steam current capacity ratio), the scope is ~ . The PID parameter is P = 300%, I = , D = 0. This group of PID parameter may enable the valve position margin of fluctuation not greatly but the return route to have the quicker track effect. The fluid position forward feed coefficient and the boiler fixed load close correlation, generally are the fixed load bigger forward feed coefficient is also bigger. This project waste heat boiler fixed load is 35t/h. The forward feed coefficient as soon as assigns according to the table, sees the attached list: The attached list forward feed is a mathematical table The scope of Level（ %） 45 45~46 46~47 47~48 48 ~ 49 Flow coefficien（ t/h） The scope of Level（ %） 49~51 51~52 52~53 53~54 54~55 55 Flow coefficien（ t/h） 0 Throws transports when first throws transports for the water current capacity single return route, after the adjustment is steady, then cuts for the steam current capacity ratio control, at the same time the fluid position forward feed the function. To the steam decides the water + fluid position forward feed ratio control plan to move transports simply convenient, after throws transports (produces steam quantitative change) after the load perturbation, the fluid position perturbation (dumps pollutants quantitative change) to test, since the anti perturbation performance has been good, throws transports moves steadily, achieves the technological requirement. Chart 4 was the realtime fluid position record curve, in which has recorded the load perturbation situation. Fluid position undulation scope 177。 3%. Chart 4 realtime fluids positions record curve 4 forever great PLC PID control system analysis brings PID the control function the FATEK programmable controller PID control and its controller or intelligent PID controller (measuring appliance) already very many, the product actual center obtained the widespread application in the project, has various PID controller product, took the domestically produced PLC enterprise, forever the great electrical machinery jointstock pany continuously will devote to the PLC research development work, will bring PID the control function the FATEK programmable controller (PLC) will be uses its closedloop control module to realize the boiler steam drum fluid position PID control, in unusual situation, when the fluid position deviation normal value will be bigger, through the PLC control system control, will be allowed fast to restore the water level, will guarantee the boiler the security sta。