# PID Percentage to EGU VI

LabVIEW 2009 PID and Fuzzy Logic Toolkit Help

Edition Date: June 2009

Part Number: 370401F-01

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Owning Palette: PID VIs

Requires: PID and Fuzzy Logic Toolkit

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.

Use the pull-down menu to select an instance of this VI.

 Select an instance PID Percentage to EGU (DBL)PID Percentage to EGU (DBL Array)

## PID Percentage to EGU (DBL)

 coerce output to range? specifies whether to coerce the output to the specified range when % span is greater than 100% or less than 0%. maximum (EGU) specifies the input value, in engineering units, corresponding to 100% of the full scale. % span specifies the input value in percentage of full scale. minimum (EGU) specifies the input value, in engineering units, corresponding to 0% of the full scale. output (EGU) returns the output value in engineering units.

## PID Percentage to EGU (DBL Array)

 coerce output to range? specifies whether to coerce the output to the specified range when % span is greater than 100% or less than 0%. maximum (EGU) specifies the input value, in engineering units, corresponding to 100% of the full scale. This VI resizes the maximum (EGU) input array to match the % span input array. % span specifies the input value in percentage of full scale. minimum (EGU) specifies the input value, in engineering units, corresponding to 0% of the full scale. This VI resizes the minimum (EGU) input array to match the % span input array. output (EGU) returns the output value in engineering units. This VI determines the length of the output (EGU) array from the size of the % span input array.

## PID Percentage to EGU Details

The DBL Array instance of this polymorphic VI can be used in multi-loop PID control applications. In this case, the length of the % span input determines the length of the output array. Other input arrays do not necessarily need to be the same length as the % span input. This VI resizes other input arrays to the same length as the % span input as follows:

• If the input array is longer than the % span input, the input array is truncated to the length of the % span input. Additional values in the array are not used.
• If the input array is shorter than the % span input, the last value of the input array is repeated until the size matches that of the % span input.

In this manner, an input value that must be used for each output calculation does not need to be specified repeatedly in the array passed into this VI. Instead, the array can consist of a single value that is used for each output calculation.

## Example

Refer to the Manual-Automatic Control with Engineering Units VI in the labview\examples\control\pid\prctrlex.llb for an example of using the PID Percentage to EGU VI.

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