预内核计算是:
- [Bot Qual.CV.Remove]=And([Bot Temp.POV.Disconnect] ; [Bot Qual.POV.Disconnect])
如果底部温度POV和底部质量POV都处于未连接状态(未连接标签设置为true),计算通过将“Remove”标签设定为true来删除底部质量CV。 - [Top Qual.CV.Remove]=And([Top Temp.POV.Disconnect]; [Top Qual.POV.Disconnect])
如果顶部温度POV和顶部质量POV都处于未连接状态(未连接标签设置为true),计算通过将“Remove”标签设定为true来删除顶部质量CV。
3. [Top Qual.CV.Priority]=Iif([Bot Qual.CV.SetrangeHighLim]-[Bot Qual.POV.Measurement]; 1;10)
如果底部质量CV超出了底部质量高限(Bot Qual POV测量值),计算将把顶部质量CV优先级减少到10。否则计算分配给顶部质量CV的CV优先级是1。 - [Sub_Debutanizer.SUB.RequestedStatus]=Not(And([Bot Qual.CV.Remove];[TOP QUAL.CV.Remove]))
如果顶部和底部质量CVs都被移走(它们的Remove标签被设定为true),计算将把Sub_Debuta子控制器的请求状态设定为0(OFF)。否则指定的子控制器请求状态为1(ON)。 - [Reflux.MV.MaxMove]=Iif([BOT QUAL.CV.SetrangeHighLim]-[BOT QUAL.POV.Measurement];100;150)
这项计算修改了Reflux的Maximum Rate of Change(最大变化率)的值。如果底部质量CV超出其上限(bottom qual POV SRHi),将回流的最大动作增加至150。否则最大动作为100。 - [Reboiler.MV.MaxMove]=Iif([BOT QUAL.CV.SetrangeHighLim]-[BOT QUAL.POV.Measurement];1;1.5)
这项计算修改了Reboil的Maximum Rate of Change(最大变化率)的值。如果底部质量CV超出其上限(bottom qual POV SRHI),将再沸的最大动作增加到1.5。否则为1。 - [DEBUTANIZER.CON.EFTrackingFilterTimeConst]=Min(Max([DEBUTANIZER.CON.EFTrackingFilterTimeConst]; 560);1060)
这项计算用来将Economic Function Tracking Filter(经济函数跟踪滤波)限制在5~60mins。
两个内核后计算是: - [ExternalOutput1.EXTOUT.Value]=[Bot Qual.CV.Reachable_ConstraintActivity]
这项计算将底部质量CV在稳态时的约束行为记录在外部位号ExternalOutput1。 - [ExternalOutput2.EXTOUT.Value]=[Top Qual.CV.Reachable_ConstraintActivity]
这项计算将顶部质量CV在稳态时的约束行为记录在外部位号ExternalOutput2。
以上所述的计算所需的两个外部位号是:
预内核计算由下式给出:
最后,内核后计算是:
下图部分显示了相应的计算报告。若要使用此功能,请在页面顶部选择“Report”选项卡。
如下所述,我们通过两个场景来探讨计算引擎的性能。
仿真1
首先让我们来考虑被称为Debutanizer Max Moves.(脱丁烷塔最大步幅)的仿真场景。General场景界面和Sub_Debutanizer界面的相关信息如下图所示。
原文:
The pre-kernel calculations are:
- [Bot Qual.CV.Remove]=And([Bot Temp.POV.Disconnect] ; [Bot Qual.POV.Disconnect])
This calculation removes the bottom quality CV by setting the “Remove” flag to true if both the bottom temperature POV and the bottom quality POV are disconnected (their disconnect flags are set to true). - [Top Qual.CV.Remove]=And([Top Temp.POV.Disconnect]; [Top Qual.POV.Disconnect])
This calculation removes the top quality CV by setting the “Remove” flag to true if both the top temperature POV and the top quality POV are disconnected (their disconnect flags are set to true). - [Top Qual.CV.Priority]=Iif([Bot Qual.CV.SetrangeHighLim]-[Bot Qual.POV.Measurement]; 1;10)
This calculation decreases the top quality CV Priority to 10 if the bottom quality CV exceeds the bottom quality high limit (Bot Qual POV measurement). Otherwise, the calculation assigns a CV Priority of 1 to the top quality CV. - [Sub_Debutanizer.SUB.RequestedStatus]=Not(And([Bot Qual.CV.Remove];[TOP QUAL.CV.Remove]))
This calculation sets the Sub_Debuta subcontroller requested status to 0 (OFF) if both the top and bottom quality CVs are removed (their Remove flags are set to true). Otherwise specify the subcontroller requested status as 1 (ON). - [Reflux.MV.MaxMove]=Iif([BOT QUAL.CV.SetrangeHighLim]-[BOT QUAL.POV.Measurement];100;150)
This calculation modifies the Maximum Rate of Change value for the Reflux. If the bottom quality CV exceeds its upper limit (bottom qual POV SRHi), increase the max move for the reflux to 150. Else use 100 for the max move. - [Reboiler.MV.MaxMove]=Iif([BOT QUAL.CV.SetrangeHighLim]-[BOT QUAL.POV.Measurement];1;1.5)
This calculation modifies the Maximum Rate of Change value for the Reboil. If the bottom quality CV exceeds its upper limit (bottom qual POV SRHI), increase the max move for the reboiler to 1.5. Else use 1. - [DEBUTANIZER.CON.EFTrackingFilterTimeConst]=Min(Max([DEBUTANIZER.CON.EFTrackingFilterTimeConst]; 560);1060)
This calculation restricts the Economic Function Tracking Filter to lie between 5 and 60 minutes.
The two post-kernel calculations are: - [ExternalOutput1.EXTOUT.Value]=[Bot Qual.CV.Reachable_ConstraintActivity]
This calculation records the constraint activity at steady state for the bottom quality CV to the external tag ExternalOutput1. - [ExternalOutput2.EXTOUT.Value]=[Top Qual.CV.Reachable_ConstraintActivity]
This calculation records the constraint activity at steady state for the top quality CV to the external tag ExternalOutput2.
The two external tags required for the calculations outlined above are:
The pre-kernel calculations are given by:
Lastly the post-kernel calculations are:
The figure below partially shows the corresponding calculations report. To access this feature select the “Report” tab at the top of the page.
We investigate the performance of the calculation engine through a couple of scenarios as described below.
Simulation 1
First consider the simulation scenario called: Debutanizer Max Moves. The General scenario page as well as the Sub_Debutanizer page with the relevant information are shown below.
2016.6.15