現(xiàn)在讓我們考慮同一個計算，但把該MV的Max Move Size設(shè)定為350。與k= 1步時的計算有相同的結(jié)果，因此CalcSPHi限依舊卡緊在CalcSPLo。然而，SMOCPro只允許PV移動到750。
|k| PV |SP| OP| dSPdV| IntCalcSPLo |IntCalcSPHi| CalcSPLo |CalcSPHi|
| ------------- |:-------------:| :-----:|
|2| 750 |750 |65| 24 |-570 |1110| 500 |1000|
下一計算還表明高限被放寬到對應(yīng)的DCS。
下圖3以圖形的方式顯示出這兩個方案的結(jié)果。在上半部分我們可以看到當SP擁有一個大的（比當前PV與SPLo的差值大，本例中是600）Max Move Size時的影響。在底部我們可以看到Max Move Size =350時的結(jié)果。在此情況下SMOCPro執(zhí)行一次后SP只移動到PV =750。此時dSPdV計算被再次執(zhí)行且CalcSPHi限被松開。
例4：樣本dSPdV仿真
現(xiàn)在我們利用兩個仿真實例來說明dSPdV計算。第一個（下圖4）展示了當OPHi限是閥位物理限制時，且不能被違反的情況。dSPdV方法通過調(diào)整SPHi限（藍色的CalcSPHi）以促使OP無法進一步動作。此SPHi修改充當了控制器預(yù)防飽和的作用。同時還可以看出只要OP不再觸碰限制，dSPdV計算將把CalcSPHi松開回SPHi限。
第二個仿真（下圖5）展示了當OP限不是物理限制而是需求限制時的情況。從圖中可以清楚地看到在給定的時間段里OP違反了OPHi限。然而，當OP越過OPHi限而處于限制之外時，dSPdV計算通過調(diào)整CalcSPHi極限減小，在保證PV帶回SP的同時，有效地把OP帶回到它的限制內(nèi)。
建立文件
要（重新）建立在線EXA控制文件，請使用UAPC輸出樹節(jié)點上的Build Files選項卡。當所有必要的設(shè)計和配置步驟都已經(jīng)完成，所有的回路信息都已經(jīng)調(diào)整，變量都已經(jīng)修訂完成時，完成這一步是必須的。
原文：
Now let us consider the same calculation but now let the Max Move Size for the MV be 350. The calculation from step k=1 yields the same result, thus the CalcSPHi limit is still clamped at CalcSPLo. However, SMOCPro only allows the PV to move to 750.
The next calculation also shows that the high limit has been relaxed to its DCS counterpart.
Figure 3 below shows graphically the results from these two scenarios. On the top part we see the effect of having a large (greater than the difference between the current PV and the SPLo, 600 in this current case) Max Move Size on the SP. On the bottom we see the result of having a Max Move Size = 350. In this case, after one SMOCPro execution the SP has only moved to PV = 750. At this point the dSPdV calculation is performed again and the CalcSPHi limit is relaxed.
Example 4. Sample dSPdV simulations.
We now present two simulations exemplifying the dSPdV calculations. The first one (Figure 4 below) shows the case when the OPHi limit is the valve’s physical limit and thus cannot be violated. The dSPdV approach adjusts the SPHi limit (CalcSPHi in blue) to reflect the fact that the OP will not be able to move any further. This SPHi modification serves as windup prevention for the controller. It is also seen that as soon as the OP comes off its limit, the dSPdV calculation relaxes the CalcSPHi back to its SPHi limit.
The second simulation (Figure 5 below) shows the case when the OP limits are not physical ones but rather desired ones. This is evident in the figure since for given periods of time the OP violates the OPHi limit. However, when the OP crosses the OPHi limit and is outside the limit, the dSPdV calculation adjusts the CalcSPHi limit decreasing it to effectively bring the OP back into its limits while at the same time bringing the PV to the SP.
Building Files
To (re)build the online EXA controller file, use the Build Files tab on the UAPC Output tree node. This process must take place after all the necessary design and configuration steps have been fulfilled and all the revisions for the loop information and variables have been finalized.
2016.7.7
