Function blocks
194 Function blocks for TwinSAFE logic components
3.27 The function block SLI
3.27.1 Functional description
The FB SLI is used to save the Position input when a rising edge is encountered at input SLI
(LatchPosition). As long as SLI is set to TRUE, the system checks whether the position is within the limits
LatchPosition - Limit neg and LatchPosition + Limit pos. If this is the case the output SLIActive is set to
TRUE. If the position leaves the defined range, SLIActive is set to FALSE. The PositionDiff output
indicates the current difference between Position and LatchPosition. A falling edge at SLIActive also
results in setting of the output PositionDiff to 0. The input data types INT16, INT32, UINT16 and UINT32
are permitted for Position. The output PositionDiff supports the output data types INT16 and INT32.
The parameters Limit pos and Limit neg are UINT32 values and are therefore always specified positive.
Figure 3-123: Function block SLI