# MCV_FadeValueLreal

This FB is a utility FB which can be used in a PLC application.

This function block is used to output a delayed change in the value at the “ValueIn” input to the “ValueOut” output.

Here the user has the option to influence the change speed by specifying “ValueMaxFadePerCall” at the input and the amount by which the current value should change at the “ValueOut” per call until the value present at “ValueIn” is reached.

Block diagram

FB parameters

VAR_INPUT
Variable name | Data type | Description
ValueIn | LREAL | Target value which should be output at the “ValueOut” output. The “ValueIn“ input is defaulted to the value 0.0.
ValueMaxFadePerCall | LREAL | Defines the change in the value currently output at the “ValueOut” output every time the function block is called. The change is effective until the same value is output at the “ValueOut” output as is present at the “ValueIn” input.

VAR_OUTPUT
Variable name | Data type | Description
ValueOut | LREAL | Current output value
Error | BOOL | Indicates TRUE when an error occurs.
ErrorID | WORD | Error identifier