案例3：储罐液位控制-MV Horizon（范围）和POV Impulse Factor（脉冲因子）-6

在上图中我们可以看到，控制器起始状态是Control（控制）模式，在第5步时我们向Inlet Flow进料流量（不可测量干扰）注入一个平均值为0，标准差为1的随机噪声信号。在第50步时，我们在维持标准差为1的噪声不变的同时，从当前的运行状况中，给入一个同样是不可测的大小为-5单位的斜坡干扰量。
对应的Sub_tank level选项卡包含如下设置：

如下图所示，首先让我们介绍储罐液位POV的Impulse Factor为0时的结果。

对于本节中我们提出的所有仿真结果，图中将包含以下4类曲线：
 （顶部）黑色曲线：Inlet Flow进料流量（不可测量干扰，UNM）；
 绿色曲线：直接添加到POV（断开连接DV）的测量噪声；
 红色曲线：Vessel Level储罐液位（CV）；
 （底部）蓝色曲线：Outlet Flow出料流量（MV）。

*Figure 13. Simulation results for the case with UNM noise and POV Impulse Factor = 0.* *图*13**：**UNM**噪声及**POV Impulse Factor=0**时的仿真结果**

如下所示，现在考虑当Impulse Factor=0.8时的情况：

Figure 14. Simulation results for the case with UNM noise and POV Impulse Factor = 0.8. 图14：UNM噪声及POV Impulse Factor=0.8时的仿真结果

最后我们观察当Impulse Factor =0.95时的情况：

Figure 15. Simulation results for the case with UNM noise and POV Impulse Factor=0.95. 图15：UNM噪声及POV Impulse Factor=0.95时的仿真结果

现在让我们重复该仿真，并向测量本身注入干扰。为了实现这一点，为相应的General（常规），Sub_tank level以及Scenario tab（情景选项卡）指定下列的参数：

需要注意的是，我们将不在General（常规）选项卡中给Inlet Flow 设定干扰阶跃。在这里，我们已经给Measurement_Noise DV添加了标准偏差和斜坡干扰。需要记住的重点是，为了使该噪声的响应接近真实，DV变量的不可见测量噪声必须断开。如下图所示，为了确保这一点，需要将Measurement_Noise的Disconnected（断开）标签设定为“True”。

以下是干扰注入到测量本身的仿真曲线。第一张图是将Impulse Factor设定为0时。

Figure 16. Simulation results for the case with measurement noise and POV Impulse Factor =0. 图16：可测量噪声及POV Impulse Factor =0时的仿真结果

接下来考虑Impulse Factor = 0.8时的情况：

Figure 17. Simulation results for the case with measurement noise and POV Impulse Factor =0.8. 图17：可测量噪声及POV Impulse Factor =0.8时的仿真结果

下图描述了Impulse Factor =0.95时的情况：

Figure 18. Simulation results for the case with measurement noise and POV Impulse Factor =0.95. 图18：可测量噪声及POV Impulse Factor =0.95时的仿真结果

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原文：
In the figure above we see that the controller starts in Control mode and at step 5 we start injecting a random noise signal with a standard deviation of 1 and mean of 0 into the Inlet Flow (unmeasured disturbance). At step 50 we ramp the same unmeasured disturbance variable -5 units from its current operating conditions while maintaining the standard deviation noise of 1 intact.
The corresponding Sub_tank level tab contains the following settings:
First let us present the resulting case with an Impulse Factor of 0 for the Vessel Level POV as shown below.
For all the simulation results that we present in this section the figures will contain the following 4 curves:
 (Top) Black curve: Inlet Flow (unmeasured disturbance, UNM)
 Green curve: measurement noise added directly to the POV (disconnected DV)
 Red curve: Vessel Level (CV)
 (Bottom) Blue curve: Outlet Flow (MV)
Now consider the case with an Impulse Factor of 0.8 as shown below.
Lastly, we see the case with an Impulse Factor of 0.95.
Now let us repeat the simulations but with the disturbance injected into the measurement itself. To achieve this, specify the following parameters in the corresponding, General or Sub_tank level, Scenario tab:
Notice how the disturbance steps into the Inlet Flow are no longer present in the General tab. In their place, we have added standard deviation and ramp disturbances to the Measurement_Noise DV. An important thing to keep in mind is that in order for this noise to act as true, unseen, measurement noise the DV variable has to be disconnected. To ensure this, set the Disconnected Flag to “True” for Measurement_Noise as shown below.
Below are the simulation plots with the disturbance injected into the measurement itself. The first figure is with the Impulse Factor set at 0.
Next, consider the case with the Impulse Factor = 0.8.
The figure below depicts the case with Impulse Factor =0.95.

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2016.5.22