其中“DRIVING FORCE”項用于處理請求的SP不可到達的情況。當由于飽和狀態SP不可到達時，此參數用于將SP帶回當前PV。
通常最后一步是針對用戶指定的SPHi和SPLo限執行最終辨識。表達式為：
其中CalcSPLo和CalcSPHi值是傳遞到SMOCPro內核用于控制器計算的（MV動作，等）。SMOCPro dSPdV概念和建議
現在我們提供了概念介紹和指南條目用于為dSPdV算法指定用戶輸入參數。樣本計算在這部分之后提出。
?總體上dSPdV計算有三個目標：
- 防止飽和OP造成控制器飽和。當OP到達它的限制時，計算的設定點限通常將與實際PV值一致，以告訴SMOPro相應的SP不可能增加或減少。
-
通過使用
DRIVING FORCE參數將不可達到的SP帶回PV。
- 主動執行“強制輸出到閥門限”，這樣當OP在極限外時，程序計算一組SP限把OP帶回到其限制范圍內。
最重要的一點是要確保dSPdV增益的符號是正確的。為了確認這一點，請仔細檢查：
? 對于那些MVs，若增加設定點將導致閥位增加（即正作用回路），則dSPdVLo和dSPdVHi是正值。
? 對于那些MVs，若增加設定點將導致閥位減小（即反作用回路），則dSPdVLo和dSPdVHi是負值。
?如果可以的話，我們建議通過AIDAPro擬合來確定閥的增益(dSPdVLo/Hi)，將MV模式設定為手動，從開環響應中收集閥位（OP）和PV的數據。
?在沒有可靠信息用于設定dSPdVLo/Hi增益的情況下，我們建議使用下列標準：
? 如果DCS儀表范圍經過適當校正的，使用下式：
? 如果DCS儀表范圍沒有經過校正的，使用下式：
?當用戶希望始終能訪問SPHi到SPLo整個范圍時，必須遵循下述步驟：
- 在DCS中將OP限設定為相應的閥門限。例如，考慮下列例子，當DCS中某個閥門的限為[-5, 105]。那么OPLo限需要設定為-5，OPHi限需要設定為105。更好地方法是將這些SMOCPro參數直接映射到對應的DCS參數。
原文：
where the “DRIVING FORCE” term handles the situation in which the requested SP is unreachable. This parameter helps to bring an SP to the current PV if the SP is unreachable due to a saturation condition.
The last step in the routine is to perform final discriminations against the user specified SPHi and SPLo limits. The expressions are:
where the values CalcSPLo and CalcSPHi are the ones passed to the SMOCPro kernel for controller calculations (MV moves, etc).
SMOCPro dSPdV Concepts and Recommendations
Now we provide a summary of the concepts presented and our guidelines for how to specify the user-inputed parameters for the dSPdV algorithm. Sample calculations are presented after this section.
? In summary the dSPdV calculation has three goals:
- Prevent controller windup for a saturated OP. The calculated set point limit will always match the actual PV value when the OP reaches its limit, telling SMOCPro that there is no corresponding SP increase or decrease possible.
- Bring an unreachable SP back to the PV via the use of the DRIVING FORCE parameter.
- Perform active "output-to-valve limit enforcement" so that whenever the OP is outside its limits, the routine calculates a set of SP limits that will bring the OP back within its limits.
? It is of utmost importance that the sign of the dSPdV gain is correct. To ensure this, double check that
? For MVs where an increase in setpoint results in an increase in valve position (i.e. a direct acting loop), the dSPdVLo and dSPdVHi values should both be POSITIVE.
? For MV's where an increase in setpoint results in a decrease in valve position (i.e. a reverse acting loop), the dSPdVLo and dSPdVHi values should both be NEGATIVE.
? If possible, we recommend determining the valve gains (dSPdVLo/Hi) by performing AIDAPro fits between the valve position (OP) and the PV from open-loop response data when the MV mode is set on manual.
? In the case where no reliable information is available for setting the dSPdVLo/Hi gains we recommend to use the following criteria:
? If the DCS instrument range is properly calibrated, use:
? If the DCS instrument range is not properly calibrated, use:
? In the case when the user wants to always have access to the entire SPHi to SPLo range, the following steps must be followed: - Set the OP limits to their corresponding valve limits in the DCS. For instance, consider an example in which the valve limits in the DCS are [-5, 105]. Here the OPLo limit needs to be set equal to -5 and the OPHi limit must be set equal to 105. Even better would be to map these SMOCPro parameters directly to the corresponding DCS parameters.
2016.7.4
