National Instruments 371685C-01 用户手册

You can use autotuning to improve controller performance. There are two ways in which you 
can autotune a controller.

•

Wizard-Based Autotuning—You can use the PID Autotuning Wizard to tune the 
parameters.

•

Classic Autotuning—You can use the functions in the Autotuning class to develop a 
custom autotuning user interface.

Complete the following steps to autotune a controller. These steps explain both wizard-based 
and classic autotuning.

1.

Call 

PidCreateWithAutotune

 to create the controller and obtain the PID handle that 

identifies that controller in subsequent function calls. The PID Library invokes the 
callback function provided to 

PidCreateWithAutotune

 when the following PID 

events occur:

•

pidNoiseEstimateEvent—Noise estimation is complete

•

pidRelayCycleEvent—A setpoint relay cycle is complete

•

pidAutotuneEvent—Autotuning is complete

When you use wizard-based autotuning, the library invokes the callback function only 
when the autotuning is complete.

2.

Provide the PV to the controller in a loop and obtain the controller output, which is again 
applied on the system.

3.

While the PID control loop is being run, call 

PidAutotuneShowDialog

 if you want to 

use wizard-based autotuning. This function launches the Autotuning Wizard. To use 
classic autotuning, call the functions in the Autotuning class.

4.

Once the control loop ends, call 

PidDiscard

 to discard the PID controller and release 

its resources.

Use the LabWindows/CVI application distribution feature to deploy applications you create 
using the PID Control Toolkit. The PID Control Toolkit installs 

CVIPIDRuntime.msm

 in the 

C:\Program Files\Common Files\Merge Modules

 directory. This file installs 

CVIPIDAtUI.dll

 in the 

system

 directory. If you deploy applications that use wizard-based 

autotuning, you must add this merge module to the distribution.

The version of LabWindows/CVI you are using determines how you add the merge module 
to the distribution. If you are using LabWindows/CVI 7.x, create a file group in the 
distribution kit named 

_MSMS_

. Include 

CVIPIDRuntime.msm

 in that file group. Build the 

distribution kit, and 

CVIPIDRuntime.msm

 will be seamlessly merged in as an MSI merge 

module, instead of just being included as a file.