Operating Principle Polyline - Siemens SIMATIC S7-1200 Function Manual

Instructions
9.5 Polyline
9.5.3

Operating principle Polyline

Polyline data
To change the polyline, you edit the values in the UserData structure. The values are then
checked for validity and transferred to the WorkingData structure. Only in the WorkingData
structure are the values used for the interpolation calculation.
The values are checked and transferred when
● You set the Validate parameter to TRUE while the Reset parameter is set to FALSE.
● Polyline is called for the first time after the change of operating state of the CPU from
STOP to RUN while the Reset parameter is set to FALSE.
If Polyline has already been called, for example in OB100, another automatic check of the
values is not performed at the subsequent calls.
If the polyline data in the UserData structure is invalid, the previous polyline data in the
WorkingData structure remains unchanged and a corresponding error message is output. If
the check was performed for the first time, no valid values are available in the WorkingData
structure and a corresponding error message is output. In this case, the Output parameter is
specified with the substitute output value that you configure with the ErrorMode tag.
The check and transfer of the values from the UserData structure requires more CPU
processing time than the interpolation calculation. In time-critical applications, the first
execution of Polyline can be in startup OB 100. In this way, the time-consuming one-time
check and transfer of the polyline data can be completed before the cyclic application
program sections.
Validity of the polyline data
When the values in the UserData structure are checked, they must meet the following
conditions so that a valid polyline is available for the interpolation calculation:
● 2 ≤ UserData.NumberOfUsedPoints ≤ 50
● UserData.Point[j].x < UserData.Point[j+1].x with index j =
1..(UserData.NumberOfUsedPoints – 1)
● -3.402823e+38 ≤ UserData.Point[i].x ≤ 3.402823e+38 with index i =
1..UserData.NumberOfUsedPoints
● -3.402823e+38 ≤ UserData.Point[i].y ≤ 3.402823e+38 with index i =
1..UserData.NumberOfUsedPoints
● UserData.Point[i].x and UserData.Point[i].y are valid REAL values (≠ NaN) with index i =
1..UserData.NumberOfUsedPoints
If one or more conditions are not met during the check, the values in the UserData structure
are not transferred to the WorkingData structure. A corresponding error message is output at
the ErrorBits (Page 518) parameter.
512
Function Manual, 03/2017, A5E35300227-AC
PID control