Emerson PACSystems RSTi-EP User Manual page 212

User Manual
GFK-2958J
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Periodic Counting/ Primary Direction Up
Figure 117: Periodic Counting, Primary Direction Up
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Counting Range
Limits
End value
Lower count limit
Detailed Description of I/O Modules
Counting (up or down) starts at the load value, the entire counting range is used.
Upon reaching a count limit, the counter jumps back to the load value and starts
counting again from there. The status bit Overflow performed, or Underflow
performed is set and a process alarm will be triggered if it is parameterized. All status
bits remain set until they are reset with the bit Reset status bits in the control word.
Up-counting starts at the load value.
If the parameterized end value -1 is reached during counting in the positive
direction, the counter jumps back to the load value at the next positive count pulse
and continues counting from there. The status bit "End value reached" is set and a
process alarm will be triggered if it is parameterized.
Upon reaching the lower count limit the counter jumps to the upper count limit to
continue counting from there. The status bit "Underflow performed" is set and a
process alarm will be triggered if it is parameterized. All status bits remain set until
they are reset with the bit "Reset status bits" in the control word.
Valid range of values
–2 147 483 647 (–2
+2 147 483 648 (–2
31 + 1) to +2 147 483 647 (2 31
31 )
Chapter 5
Oct 2019
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