PID algorithm for 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. This function block also features manual mode control with bumpless manual to automatic transitions, nonlinear integral action, two degree of freedom control, and error-squared control. You can use this function block to operate on one input value at a time.


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Dialog Box Options

Option Description
Inputs Contains the following configuration options:
  • Terminal name—Contains the name of the block diagram terminal to configure.
  • Visible?—Specifies whether to display the terminal on the block diagram.
  • Variable scope—Specifies the availability and scope of the variable associated with the terminal. Select Single-process to use a single-process shared variable. Select Network-published to use a network-published shared variable. Select No Variable if you do not want to use a terminal variable. To minimize overhead, include function block terminal variables only when necessary. If you change the Variable scope to No Variable after creating the function block instance, LabVIEW deletes the terminal variable.
  • Data source—Specifies the data source of the input. Select Terminal to wire the input value to the terminal on the block diagram. Select Variable to supply the input value to the function block through the associated terminal variable, if available. Select Default value to use the Default value. The Variable data source option is not available if you select No Variable under Variable Scope. If you select Terminal as the data source and leave the block diagram terminal unwired, LabVIEW uses the Default value.
  • Default value—Specifies the default value of the input. If you select Variable as the data source, LabVIEW uses this value as the initial value of the variable. If you select Default value as the data source, LabVIEW uses this value for every iteration of the function block.
Outputs Contains the following configuration options:
  • Terminal name—Contains the name of the block diagram terminal to configure.
  • Visible?—Specifies whether to display the terminal on the block diagram.
  • Variable scope—Specifies the availability and scope of the variable associated with the terminal. Select Single-process to use a single-process shared variable. Select Network-published to use a network-published shared variable. Select No Variable if you do not want to use a terminal variable. To minimize overhead, include function block terminal variables only when necessary. If you change the Variable scope to No Variable after creating the function block instance, LabVIEW deletes the terminal variable.

Inputs/Outputs

  • cerrcodeclst.png error in —

    error in describes error conditions that occur before this node runs. This input provides standard error in functionality.

  • cdbl.png process variable —

    Specifies the current value of the variable that you are controlling.

  • cdbl.png integral time (Ti, min) —

    Specifies the PID parameter (Ti) that adjusts the effect of the error integral term on the output.

  • cbool.png auto? (T) —

    TRUE selects automatic control (default), FALSE selects manual mode. The function block uses bumpless transfer to transition from manual mode to automatic control.

  • cdbl.png derivative time (Td, min) —

    Specifies the PID parameter (Td) that adjusts the effect of the error derivative term on the output.

  • cdbl.png setpoint —

    Specifies the setpoint value of the process variable that you are controlling. This is the desired value for the process variable.

  • cdbl.png proportional gain (Kc) —

    Specifies the proportional gain (Kc) of the PID algorithm. The default value is 1.

  • idbl.png output —

    Returns the control output of the PID algorithm that is applied to the controlled process.

  • ierrcodeclst.png error out —

    error out contains error information. This output provides standard error out functionality.