Cpu Sweep Modes; Figure 11: Typical Sweeps In Normal Sweep Mode - Emerson PACSystems RX3i User Manual

PACSystems™ RX3i and RSTi-EP CPU Reference Manual
GFK-2222AK
4.1.2

CPU Sweep Modes

4.1.2.1 Normal Sweep Mode
In Normal Sweep mode, each sweep can consume a variable amount of time. The Logic
window is executed in its entirety each sweep. The Communications windows can be set
to execute in a Limited or Run-to-Completion mode. Normal Sweep is the most common
sweep mode used for control system applications.
The following figure illustrates three successive CPU sweeps in Normal Sweep mode. Note
that the total sweep times may vary due to sweep-to-sweep variations in the Logic
window, Communications windows, and Background window.

Figure 11: Typical Sweeps in Normal Sweep Mode

CPU Operation
SWEEP n
HK
INPUT
LOGIC
OUTPUT
CC
BPC
BG
Abbreviations:
HK = Housekeeping
CC = Controller Communications Window
BPC = Backplane Communications Window
BG = Background Window
SWEEP n+1 SWEEP n+2
HK HK
INPUT INPUT
LOGIC LOGIC
OUTPUT
CC
BPC
BG
OUTPUT
CC
BPC
BG
Section 4
October 2019
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