Allen-Bradley Logix5000

Rockwell Automation Publication 1756-RM003N-EN-P - October 2011 665
Function Block Attributes Appendix B
Overview of Timing Modes
The following diagram shows how an instruction determines the appropriate
timing mode.
TimingMode = 2TimingMode = 1TimingMode = 0
Determine Time-base Mode
Real Time TimingOversample TimingPeriodic Timing
Determine Task Type
Periodic Task Event or Continuous Task
DeltaT = OversampleDT
If DeltaT < 0 or DeltaT > 4194.303 s the
instruction sets DeltaT = 0.0 and sets the
appropriate bit in Status.
If DeltaT > 0, the instruction executes.
DeltaT = RTSTimeStamp
n
- RTSTimeStamp
n-1
If DeltaT > 0, the instruction executes.
If |RTSTIME - DeltaT| > 1, the instruction sets RTSMissed
bit in Status.
DeltaT = Task scan time
If DeltaT > 0, the instruction executes.
DeltaT = Elapsed time since last execution
If DeltaT > 0, the instruction executes.