EMERSON艾默生VE4022控制器控制站采用plx系统,用于完成对加热炉的热工控制和过程参数检测。该系统的处理器1757pl*52a是rockwell专用处理器,具有8mram,高速底板与网络融为一体,i/o模块可带电插拨,并可以任意安排。在该系统中,控制站共设有1个主机架和2个扩展机架,完成了整个加热炉的6段温度控制、60多点的模拟量检测及20多个开关量的输入和输出。系统模板采用如下:4个756 of6ci/a模块、9个1756ib16d/a模块、2个1756ow16i模块、4个1756if6i/a模块、5个1756ir6i/a模块、4个1756it6i/a模块。为提高本系统的可靠量,所有ai、di和do均与现场进行了隔离,ai模板还选用了通道和通道间均有隔离的双隔离模板。按照确定的控制规则进行编程,根据加热炉的工况选择使用。将现场信号采样﹑燃气流量模糊控制回路﹑空气流量模糊控制回路﹑温度模糊控制回路编成子程序,模块化,在主程序中调用,以利于调试和控制功能组态。该网络属于无源的高性能多元总线,5m的传输速度。数据传输采用确定性的传输方式,大大减少了数据传输量,现场仪表控制阀采用耐高温的控制阀,执行机构采用气动执行机构,压力和差压变送器采用fisher 3051变送器。
VE4022
电流型控制是指将误差放大器输出信号与采样到的电感峰值电流进行比较．从而对输出脉冲的占空比进行控制，使输出的电感峰值电流随误差电压变化而变化。电流控制型是一个一阶系统，而一阶系统是无条件的稳定系统。是在传统的PWM电压控制的基础上，增加电流负反馈环节，使其成为一个双环控制系统，让电感电流不在是一个独立的变量，从而使开关变换器的二阶模型变成了一个一阶系统。信号。与单一闭环的电压控制模式相比，电流模式控制是双闭环控制系统，外环由输出电压反馈电路形成，内环由互感器采样输出电感电流形成。在该双环控制中，由电压外环控制电流内环，即内环电流在每一开关周期内上升，直至达到电压外环设定的误差电压阂值。电流内环是瞬时快速进行逐个脉冲比较工作的，并且监测输出电感电流的动态变化，电压外环只负责控制输出电压。因此电流型控制模式具有比起电压型控制模式大得多的带宽。
VE4022
The EMERSON Emerson VE4022 controller control station uses a PLX system to complete thermal control and process parameter detection of the heating furnace. The processor 1757pl * 52a of this system is a Rockwell dedicated processor with 8mRAM. The high-speed backplane is integrated with the network, and the I/O module can be powered and arranged arbitrarily. In this system, the control station is equipped with one main frame and two expansion frames, which complete the 6-stage temperature control of the entire heating furnace, more than 60 analog quantity detection points, and more than 20 switch quantity inputs and outputs. The system template adopts the following: 4 756 of 6ci/a modules, 9 1756ib16d/a modules, 2 1756ow16i modules, 4 1756if6i/a modules, 5 1756ir6i/a modules, and 4 1756it6i/a modules. To improve the reliability of this system, all AI, DI, and DO have been isolated from the site. The AI template also uses a dual isolation template with isolation between channels and channels. Program according to the established control rules and choose to use according to the working conditions of the heating furnace. The field signal sampling, gas flow fuzzy control loop, air flow fuzzy control loop, and temperature fuzzy control loop are programmed into subprograms, modularized, and called in the main program to facilitate debugging and control function configuration. This network belongs to a passive high-performance multi bus with a transmission speed of 5m. The data transmission adopts a deterministic transmission method, greatly reducing the amount of data transmission. The on-site instrument control valve adopts a high-temperature resistant control valve, the actuator adopts a pneumatic actuator, and the pressure and differential pressure transmitter adopts a Fisher 3051 transmitter.
VE4022
Current type control refers to comparing the output signal of the error amplifier with the sampled peak inductance current, in order to control the duty cycle of the output pulse and make the output peak inductance current change with the error voltage. The current controlled type is a first-order system, which is unconditionally stable. On the basis of traditional PWM voltage control, a current negative feedback link is added to make it a dual loop control system, so that the inductance current is no longer an independent variable, thus transforming the second-order model of the switching converter into a first-order system. Signal. Compared with a single closed-loop voltage control mode, current mode control is a dual closed-loop control system, with an outer loop formed by an output voltage feedback circuit and an inner loop formed by a transformer sampling output inductance current. In this dual loop control, the voltage outer loop controls the current inner loop, meaning that the inner loop current rises during each switching cycle until it reaches the error voltage threshold set by the voltage outer loop. The current inner loop is used for instantaneous and rapid pulse by pulse comparison, and monitors the dynamic changes of the output inductance current. The voltage outer loop is only responsible for controlling the output voltage. Therefore, the current based control mode has a much larger bandwidth than the voltage based control mode.
VE4022
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