BENTLY 3500/05-01-02-00-00-00框架
（0-100%范围）说明了典型的自动调谐练习。变量1表示阀门，变量2表示过程。在这个例如，该过程具有标准偏差小于0.5%的噪声。已设置%HYS（%滞后带）
设置为0.75%，并设置%DEV（%与设定点的偏差，该偏差应设置为%HYS值的至少4倍）至3%。
自动调谐器将在第一个1期间使用初始阀门步长（在控制器功能块中设置为%步长）-1/2个周期来学习过程的近似增益。然后，它将在以下步骤的剩余时间内调整阀门步长：用于维护%DEV设置的自动调整练习。此测试结束时，建议的设置为并进行20%的设定点改变，以说明控制器的调整。
当为下一次自动调谐练习启动自动调谐时，它将使用上一次学习的过程增益确定阀门步长的练习，除非：控制器块中复位时的参数已存储为是，在第一次测试期间出现警告，或电站已通电。过程噪声-可能会导致自动调谐不会产生周期性阀门循环。自动调谐器将完成练习，但结果可能不令人满意。这在图2中的第一个自动调整练习中进行了说明这是与图1相同的过程，但%HYS设置为0.5%。如果这些结果发生在控制器%
HYS已设置为A（自动设置滞后）
控制器可能难以获得良好的噪声系数，并且应考虑手动输入%HYS参数。%HYS值应至少增加到噪声标准偏差值的两倍。在噪声幅度非常大的情况下，滤波器打开应增加模拟输入，以最小化控制器看到的噪声幅度。价值%DEV参数应设置为%HYS值的至少四倍，以获得最佳结果。
稳态条件-必须在开始自动调谐练习之前为过程和控制器建立。自动调谐器可以在手动或自动模式下启动。当当前阀门信号达到以下状态时，达到稳定状态：使过程达到其当前值，并且设定点等于过程。当不处于稳定状态时，阀门周期将不是对称的，如图2中的第二次调整练习所示，或者，在更坏的情况下
阀门可能根本不循环。如果阀门确实循环，尽管不是对称的，但仍会有足够的调节结果获得。自动调谐警告-不终止自动调谐练习，通常通过增加%来消除HYS和/或%DEV设置。在某些情况下，它们可能是由以下过程中发生的负载变化引起的：自动调谐练习。自动调谐仍将导出推荐的调谐值，但不会自动导出如果请求该功能，则传输到控制器。按下确认键可清除警告按钮
Chart 1 (0-100% range) illustrates a typical autotune exercise. Variable 1 is the Valve and 2 the Process. In this
example, the process has noise with a standard deviation of less than 0.5%. The % HYS (% hysteresis band) is set
to 0.75% and the % DEV (% deviation from setpoint which should be set to at least 4 times the % HYS value) is set
to 3%.
The autotuner will use the initial valve step size (set as % STEP in the controller function block) during the first 1-
1/2 cycles to learn the approximate gain of the process. It will then adjust the valve step size during the remainder of
the autotuning exercise to maintain the % DEV setting. When this test concludes, the recommended settings are
transferred to the controller and a 20% setpoint change is made to illustrate the controller tuning.
When the autotuner is started for the next autotune exercise, it will use the process gain learned during the previous
exercise to determine the valve step size unless: the parameter AT RESET in the controller block has been stored as
YES, warnings occurred during the first test, or the station has been power cycled. Process Noise - could have an effect where the autotuner will not produce periodic valve cycles. The autotuner will
complete an exercise but results may not be satisfactory. This is illustrated in the first autotuning exercise in chart 2
which is the same process as chart 1 but the % HYS was set at 0.5%. If these results occur when the controller %
HYS has been set to A (auto set hysteresis) the controller may be having difficulty deriving a good noise figure and
manual entry of the % HYS parameter should be considered. The % HYS value should be increased to at least
twice the standard deviation value of the noise. In cases where the noise amplitude is extremely large, the filter on
the analog input should be increased to minimize the amplitude of the noise seen by the controller. The value of the
% DEV parameter should be set to at least four time the % HYS value for best results.
Steady State Conditions - must be established for the process and controller prior to starting an autotune exercise.
The autotuner can be initiated while in manual or auto. Steady state is reached when the present valve signal has
brought the process to its present value, and the setpoint is equal to the process. When not at steady state, valve
cycles will not be symmetrical as illustrated in the second tuning exercise in chart 2 or, as a worse case situation, the
valve may not cycle at all. If the valve is does cycle, although not symmetrically, adequate tuning results will still
be obtained. Autotuner Warnings - do not terminate the autotune exercise and are normally eliminated by increasing the %
HYS and/or the % DEV settings. In some cases, they may have been caused by load changes that occurred during
the autotune exercise. The autotuner will still derive recommended tuning values but they will not automatically be
transferred to the controller, if that feature was requested. The warnings can be cleared by pressing the ACK
button.
