Designing a Controller-Sub-contr
进入子控制器标签屏幕后，相应的子模型（包含在子控制器内且在不同的MVs/DVs和POVs间配对搭建）动态离散化和分析结果如下：
•系统在子控制器周期内离散化，并产生离散的状态空间子模型。
•静态作用增益将被计算，即操作输入与输出间的增益将被计算。这些增益可用于稳定时间估计和MV/CV权重关系（见整定建议一节）。
•动态行为的延迟和/或稳定时间是在计算静态动作增益和离散化子模型（到一千步）仿真的基础上估计的。设定时间用于计算默认的压实点。
注：强烈建议对斜坡模型不要使用并行通道结构，即，将一个输出表达成两个或以上斜坡的叠加。如果模型中使用了这样的结构，控制器编译过程将失败。
注：当动态离散化相对于采样速率太慢，使得稳定时间未能充分估计时，将出现以下消息。通常可通过增加子控制器周期来解决该问题。
子控制器摘要选项卡
下图包含了子控制器摘要选项卡的主要组成部分。
子控制器摘要选项卡字段
Sub-controller Name（子控制器名） 子控制器名；可编辑。
**SubControl Period（子控制器周期）(DT) **子控制器的采样周期。这个量被表示为模型（全体控制器）采样周期的正整数倍，且缺省值是1。该值是可编辑的。
SubControl Period （子控制器周期）(min) 以时间单位（mins或secs）表示的子控制器控制周期。其对应于子控制器周期(DT)输入乘以模型采样周期。该值是可编辑的。
Offset（偏移量） (DT) 子控制器的偏移量限制了子控制器在子控制周期内运行的时间。 ‘offset（偏移量）’是总模型周期乘以一个非负数得到的，其应该比子控制器周期更小。
Blending Sub-controller（混合子控制器） 该复选框用于将选定的子控制器指定为混合器。混合子控制器具有以下算法：
•所有的MVs和DVs都是比值；
•仅在稳态时计算MV比值；
•SMOCPro自动为比例之和（通常为1）创建一个隐藏约束。
原文：
Upon entering the sub-controller tab-screens, the corresponding dynamics of the sub-model (contained in the sub-controller and constructed from the pairing of the different MVs/DVs and POVs) are discretized and analyzed with the following results:
• The discretization is performed with the sub-controller period and leads to a discrete state-space sub-model.
• The static action gains are computed, i.e. the gains between the manipulated inputs and the outputs are computed. These gains are used in the settling time estimation and in the MV/CV weight relationships (see below - Tuning advice).
• The delay and/or settling times of the action dynamics are estimated on the basis of a simulation of the discretized sub-model (up to a thousand steps) and the computed static action gains. The settling time is used to compute the default compaction points.
NOTE: It is strongly recommended NOT to use a parallel pass structure with ramps i.e., express an output as the sum of two or more ramps. The controller compile process will fail if such a structure is used in the model.
NOTE: In case the discretized dynamics are too slow relative to the sampling rate, the settling time fails to be adequately estimated and the following message appears. Typically, increasing the sub-control period resolves the problem.
Sub-controller Summary Tab
The figure below contains the main components of the Sub-controller Summary tab.
Sub-controller Summary Tab Fields
Sub-controller Name The name of the sub-controller. Editing is possible.
SubControl Period (DT) The sampling period for a sub-controller. This quantity is expressed as a positive integer multiplier of the model (and overall controller) sampling period whose default value is one. This value can be edited.
**SubControl Period (min) **The control period of a sub-controller in time units (minutes or seconds). It corresponds to the Sub-control Period (DT) entry multiplied by the model (controller) sampling period. This value cannot be edited.
Offset (DT) The offset for a sub-controller defines the time at which the sub-controller will run within the sub-control period. The ‘offset’ is a non-negative multiplier of the overall model period and should be smaller than the sub-controller period.
Blending Sub-controller Check box for specifying the selected sub-controller as a blender. A blending sub-controller has the following special computation procedures:
• All MVs and DVs are ratios
• MV ratios are computed at steady state only
• SMOCPro automatically creates a hidden constraint for the sum of ratios (always at one).
2016.9.12
