该功能在测试共线操作变量(MVs)时有用。
智能向导应用提供了允许一个MV（主要）与另一个MV（次要）配对的功能，这样当主MV阶跃动作时，副MV亦同时做阶跃动作。你可以通过STPAIRREQ参数打开或关闭此功能。
参数STPAIRRATIO定义了副MV与主MV的阶跃大小之比。若比值为正，则两个MV将往相同方向做阶跃。与此相反，若比值为负，则两个MV将往相反方向做阶跃。
配对变量必须配置在相同的测试组里。否则，智能向导引擎将会忽略MV配对要求。
当启用一对配对MV时，主MV和副MV将同时做阶跃动作。在测试组中主副MV的这一同时动作将被当成单个阶跃。测试组在完成配对MV动作后在序列上进入下一MV。
只要配对MV在同一个测试组，没有限制哪个MV是主要的哪个MV是次要的。例如，你可以指定MV2作为MV1（主要）的配对变量，而在同一时间指定MV1作为MV2（主要）的配对变量。
如果你在各自的STPAIRRATIO中依旧使用不同的标记，智能向导引擎将自动生两个不同的配对动作：一个同向，一个反向。

附原文：
This feature may be useful for testing colinear manipulated variables (MVs).
A SmartStep application provides the functionality of allowing one MV (primary) to be paired up with another MV (secondary), such that when the primary MV steps, the secondary MV is simultaneously stepped also. You can turn this feature on or off via parameter STPAIRREQ.
The parameter STPAIRRATIO defines the ratio of the secondary MV step size over the primary MV. A positive ratio means both will step in the same direction. In contrast, a negative ratio will step the paired MVs in the opposite direction.
Paired variables must be configured in the same testing group. Otherwise, the SmartStep engine will ignore the MV pair request.
When a paired MV is enabled, both the primary and secondary MVs are stepped simultaneously.This simultaneous move of the primary MV step and secondary MV step is treated as a single step in the testing group. The testing group proceeds to the next MV in sequence on completion of the paired MV moves.
There is no restriction on which MV can be the primary and which should be secondary, as long as they are in the same testing group. For example, you can specify MV2 as a paired variable in MV1 (primary), while at the same time specifying MV1 as the paired variable in MV2 (primary).
If you also use different signs in the respective STPAIRRATIO, then the SmartStep engine will automatically generate two different paired moves: one in the same direction and the other in the opposite direction.

2015.10.17