其中“DRIVING FORCE”项用于处理请求的SP不可到达的情况。当由于饱和状态SP不可到达时，此参数用于将SP带回当前PV。
通常最后一步是针对用户指定的SPHi和SPLo限执行最终辨识。表达式为：
其中CalcSPLo和CalcSPHi值是传递到SMOCPro内核用于控制器计算的（MV动作，等）。SMOCPro dSPdV概念和建议
现在我们提供了概念介绍和指南条目用于为dSPdV算法指定用户输入参数。样本计算在这部分之后提出。
•总体上dSPdV计算有三个目标：
- 防止饱和OP造成控制器饱和。当OP到达它的限制时，计算的设定点限通常将与实际PV值一致，以告诉SMOPro相应的SP不可能增加或减少。
-
通过使用
DRIVING FORCE参数将不可达到的SP带回PV。
- 主动执行“强制输出到阀门限”，这样当OP在极限外时，程序计算一组SP限把OP带回到其限制范围内。
最重要的一点是要确保dSPdV增益的符号是正确的。为了确认这一点，请仔细检查：
对于那些MVs，若增加设定点将导致阀位增加（即正作用回路），则dSPdVLo和dSPdVHi是正值。
对于那些MVs，若增加设定点将导致阀位减小（即反作用回路），则dSPdVLo和dSPdVHi是负值。
•如果可以的话，我们建议通过AIDAPro拟合来确定阀的增益(dSPdVLo/Hi)，将MV模式设定为手动，从开环响应中收集阀位（OP）和PV的数据。
•在没有可靠信息用于设定dSPdVLo/Hi增益的情况下，我们建议使用下列标准：
如果DCS仪表范围经过适当校正的，使用下式：
如果DCS仪表范围没有经过校正的，使用下式：
•当用户希望始终能访问SPHi到SPLo整个范围时，必须遵循下述步骤：
- 在DCS中将OP限设定为相应的阀门限。例如，考虑下列例子，当DCS中某个阀门的限为[-5, 105]。那么OPLo限需要设定为-5，OPHi限需要设定为105。更好地方法是将这些SMOCPro参数直接映射到对应的DCS参数。
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
