National Instruments 371685C-01 - page 28

Chapter 3 Using the PID Control Toolkit

© National Instruments Corporation 3-11 LabWindows/CVI PID Control Toolkit User Manual

The control loops can be timed in the following ways:

•Software-Timed—In software-timed control loops, the timing is controlled by the

software loop rate. You can implement a software loop with a timer construct, such as a

timer control or asynchronous timer, or a while loop with a delay or sleep operation at

the end.

•Hardware-Timed—In hardware-timed control loops, the timing is controlled by the

DAQ device. The DAQ device is configured with the appropriate sample rate, and the

sample mode is set to hardware-timed.

For more information about DAQ, refer to the NI-DAQmx Help or Traditional NI-DAQ

(Legacy) C Function Reference Help, depending on the DAQ API you are using. Also refer

to the DAQ example programs.

Contents

Main Page Important Information Warranty Copyright Trademarks Patents Contents Page About This Manual Conventions Related Documentation Overview of the PID Control Toolkit System Requirements Installation Instructions Activation Instructions PID Control Toolkit Applications PID Control PID Algorithms The PID Algorithm Implementing the PID Algorithm with the PID Functions Error Calculation Proportional Action The Precise PID Algorithm Error Calculation Proportional Action Trapezoidal Integration The Autotuning Algorithm Tuning Formulas Page Page Using the PID Control Toolkit Designing a Control Strategy Setting Timing Tuning Controllers Manually Closed-Loop (Ultimate Gain) Tuning Procedure Open-Loop (Step Test) Tuning Procedure Using the PID Library PID Controller PID Algorithms Control Input Filter Output Rate Limiting Using PID with Autotuning Distributing Applications That Use Wizard-Based Autotuning Using PID with Gain Scheduling Using PID with Lead-Lag Using PID with Setpoint Profiling Using Ramp Generators Converting between Percentage of Full Scale and Engineering Units Using PID on Real-Time (RT) Targets Using PID with DAQ Devices Page A References B Technical Support and Professional Services Page Glossary A B C Page Page O P Page Index A B C D I K L N O S T U W Z