由于斜坡变量的不稳定性，智能向导测试应用程序提供了一个特殊的机制来处理斜坡变量，以便将其保持在控制之下，而相关联的独立变量仍然可以做阶跃动作。
每个斜坡变量（真斜或伪斜）都将与由参数STRAMPMVS定义的MV列表相关联。这些MV都被假定为对斜坡变量具有显著的影响，可通过对应的模型曲线证明。
在阶跃测试过程中，其中一个列表中的MV将作为活跃斜坡处理。这意味着将仅通过移动该MV来完成整定斜坡的过程。
活跃斜坡处理由参数STRAMPACTMV定义。然而，如果指定的活跃斜坡处理不可用（即它处于不在服务或坏状态时），智能向导引擎将自动拾取列表中下一个可用的斜坡处理。
只有当斜坡变量以一定方式触碰到上下限时，斜坡处理变量将启动一个阶跃。事情发生基于下列条件：
• 当前斜坡测量值在（STCVMAX - STCVDELTA）与（STCVMIN+ STCVDELTA）范围之外，并且稳态预测值在（STCVMAX+ STCVDELTA）与（STCVMIN - STCVDELTA）范围之外。
-或者-
• 当前斜坡测量值与稳态预测值都在STCVMAX~STCVMIN范围之外。
当这种情况发生时，智能向导引擎将对该斜坡处理变量写入一个阶跃动作，阶跃大小将通过使斜坡变量转向并朝着规定斜率相反限制决定。
斜率由STRAMPRT参数定义：斜率越大阶跃越大。不同于普通的MV，斜坡处理变量的测试信号没有任何脉冲叠加。
一个应用程序中可以包含多个斜坡变量。当任一个MV的阶跃影响到斜坡变量时，智能向导引擎将考虑这一影响，以及兼顾分配到该斜坡变量的斜坡处理能力。因此，斜坡处理变量将始终保留有足够的空间用于必要时将斜坡环绕。
在智能向导应用中斜坡变量始终拥有较高的优先级。如果一个斜坡变量触碰到限制，但移动斜坡处理变量可能会导致另一CV违反限制，那么智能向导引擎将依旧写入斜坡处理动作以使斜坡返回。在这种情况下，为了避免其它CV违反约束太多，应用程序将使用STRAMPRT的十分之一，以代替原来整个需求斜率。
注：若智能向导应用处于TEST模式（包括TEST NO-PULSE）运行时，所有的斜坡变量都被视为非关键变量。只有所有测试组都不处于测试模式时，斜坡变量的原始设置才将得到遵守。
附原文：
Due to the unstable nature of a ramp variable, a SmartStep tester application provides a special mechanism to handle a ramp variable so that it will remain under control, while associated independent variables can still make step moves.
Each ramp variable (true or pseudo ramp) will be associated with a list of manipulated variables specified in parameter STRAMPMVS. These manipulated variables are assumed to have significant impact to the ramp variable, as evidenced in their model curves.
During the course of step testing, one of the manipulated variables in the list will become an active ramp handle. This means, this manipulated variable will be moved solely for the purpose of turning the ramp.
The active ramp handle is specified by parameter STRAMPACTMV. However, if the specified active ramp handle is not available (that is, it is out of service or has a bad status), the SmartStep engine automatically picks up the next available ramp handle in the list.
The ramp handle variable will initiate a step only when the ramp variable hits its upper or lower limit in a certain way. Occurences are based on the following conditions:
•If current ramp measurement is outside the range between (STCVMAX – STCVDELTA) and (STCVMIN + STCVDELTA), and the steady-state prediction is outside the range between (STCVMAX + STCVDELTA) and (STCVMIN - STCVDELTA).
-or-
•If both current ramp measurement and steady-state prediction are outside the range between STCVMAX and STCVMIN.
When this occurs, the SmartStep engine will make a step move on this ramp handle variable, and the step size will have such a value that the ramp variable will turn and move toward the opposite limit with a prescribed ramp rate.
The ramp rate is specified in parameter STRAMPRT: the larger the ramp rate the bigger the step size. Unlike a regular manipulated variable, a ramp handle variable does not have any pulses superimposed on its test signal.
There can be multiple ramp variables in an application. When stepping any manipulated variable that has impact on a ramp variable, the SmartStep engine will consider this impact, as well as taking into account the capability of the ramp handle assigned to this ramp variable. As such, the ramp handle variable will always reserve adequate room available to turn a ramp around when necessary.
A ramp variable is always treated in a higher priority in a SmartStep application. If a ramp variable hits a limit, but moving the ramp handle variable may cause another controlled variable to violate its limit, then the SmartStep engine will still move the ramp handle to turn back the ramp. In this case, only one tenth of STRAMPRT will be used, instead of the full requested ramp rate, in order to prevent the other controlled variable from violating its limit too much.
Note: When the SmartStep application runs in TEST mode (including TEST NO-PULSE), all ramp variables are treated as non- critical variables. The original setting for a ramp variable will be honored only after all testing groups are not in test mode.
2015.10.15
