PID VIs

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LabVIEW 2009 PID and Fuzzy Logic Toolkit Help

Edition Date: June 2009

Part Number: 370401F-01

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Requires: PID and Fuzzy Logic Toolkit. This topic might not match its corresponding palette in LabVIEW depending on your operating system, licensed product(s), and target.

Use the PID VIs to implement PID control applications. The first three VIs on the PID palette are different versions of the PID VI. These VIs can be used interchangeably depending on the needs of the application. The other VIs on the PID palette can be used with one of the PID VIs for additional functionality.

Palette Object	Description
PID	Implements a PID controller using a PID algorithm for simple PID applications or high speed control applications that require an efficient algorithm. The PID algorithm features control output range limiting with integrator anti-windup and bumpless controller output for PID gain changes. Use the DBL instance of this VI to implement a single control loop. Use the DBL Array instance to implement parallel multi-loop control.
PID Advanced	Implements a PID controller using a PID algorithm with advanced optional features. The PID algorithm includes the features of the algorithm the PID VI uses, as well as manual mode control with bumpless manual-to-automatic transitions, non-linear integral action, two degree-of-freedom control, and error-squared control. Use the DBL instance of this VI to implement a single control loop. Use the DBL Array instance to implement parallel multi-loop control.
PID Autotuning	Includes the Autotuning Wizard in addition to the basic PID algorithm. You can use this VI instead of the PID VI, which implements a basic PID algorithm. Use the additional inputs and output of this VI to set autotuning parameters, invoke the Autotuning Wizard, and update the PID gains.
PID Control Input Filter	Applies a fifth-order lowpass finite impulse response (FIR) filter to the input value. Filter cut-off frequency is designed to be 1/10 of the sample frequency of the input value. Use this VI to filter measured values, such as the process variable, in control applications. Use the DBL instance of this VI to implement a single control loop. Use the DBL Array instance to implement parallel multi-loop control.
PID EGU to Percentage	Converts an engineering-units input to a percent-of-range output based on the minimum and maximum range settings. Use the DBL instance of this VI to implement a single control loop. Use the DBL Array instance to implement parallel multi-loop control.
PID Gain Schedule	Selects a set of PID gains from a gain schedule for the control of processes that require different sets of gains for different regions of operation, such as highly nonlinear processes. Use the DBL instance of this VI to implement a single control loop. Use the DBL Array instance to implement parallel multi-loop control.
PID Lead-Lag	Implements a PID controller with a lead/lag function, which is generally used as a dynamic compensator in feedforward control schemes. This VI uses a positional algorithm and is an approximation of a true exponential lead/lag. Use the DBL instance of this VI to implement a single control loop. Use the DBL Array instance to implement parallel multi-loop control.
PID Output Rate Limiter	Limits the rate of change of the controller output. Place this VI immediately after the PID VI in your control application. Use the DBL instance of this VI to implement a single control loop. Use the DBL Array instance to implement parallel multi-loop control.
PID Percentage to EGU	Converts a percent-of-range input to an engineering-units output based on the minimum and maximum range settings. The output is normally limited to the range [max...min]. Values outside of the range [max..min] are allowed when coerce output to range? is FALSE. Use the DBL instance of this VI to implement a single control loop. Use the DBL Array instance to implement parallel multi-loop control.
PID Setpoint Profile	Generates setpoint values over time in a control loop for ramp and soak types of control applications.