Siemens SIMATIC S7-1200 Function Manual page 515

Enable behavior EN/ENO
If one of the following conditions is met, enable output ENO is set to FALSE.
● Enable input EN is set to TRUE and the Output parameter is specified by a substitute
output value in case of error messages ErrorBits ≥ 16#0001_0000.
● Enable input EN is set to FALSE.
If enable input EN is set to TRUE and the Output parameter can be determined as follows,
enable output ENO is set to TRUE:
● With valid interpolation calculation when Reset = FALSE.
or
● With valid SubstituteOutput parameter when Reset = TRUE.
Currently utilized points
The NextXIndex index outputs the index of the next higher x-value for the current input
value. You can use this to determine the points that are being used for the current
interpolation calculation.
WorkingData.Point[NextXIndex-1].x < Input ≤ WorkingData.Point[NextXIndex].x
Example:
● If the value of the Input parameter is between WorkingData.Point[3].x and
WorkingData.Point[4].x, the NextXIndex tag has the value 4.
● If the value of the Input parameter is less than WorkingData.Point[1].x, the NextXIndex
tag has the value 1.
● If the value of the Input parameter is greater than
WorkingData.Point[WorkingData.NumberOfUsedPoints].x and is thus greater than the
last x-value of the polyline, the NextXIndex tag has the value of the
WorkingData.NumberOfUsedPoints + 1 tag. Consequently, maximum permissible value
of the NextXIndex tag is 51.
PID control
Function Manual, 03/2017, A5E35300227-AC
Instructions
9.5 Polyline
515