Cpu Operation - Emerson PACSystems RX3i User Manual

Section 4:
This Section describes the operating modes of a PACSystems CPU and describes the tasks
the CPU carries out during these modes. The following topics are discussed:
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Switch Position
RUN I/O or
RUN I/O Enable
RUN or
RUN Output
Disable
STOP
The RUN/STOP Switch can be disabled in the programming software HWC. The memory
protection function of the switch can be disabled separately in HWC. The RUN/STOP
Switch is enabled by default. The memory protection functionality is disabled by default.
The Read Switch Position (Switch_Pos) function allows the logic to read the current
position of the RUN/STOP Switch, as well as the mode for which the switch is configured.
For details, refer to PACSystems RX3i and RSTi-EP CPU Programmer's Reference Manual, GFK-
2950.
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CPU Operation

CPU Operation
CPU Sweep
Program Scheduling Modes
Window Modes
Data Coherency in Communications Windows
Run/Stop Operations
Flash Memory Operation
RUN/STOP Switch Operation
The RUN/STOP Switch is a 3-position switch which operates as follows:
CPU and Sweep Mode
The CPU runs with I/O sweep enabled.
The CPU runs with outputs disabled.
The CPU is not allowed to go into RUN
Mode.
Logic/Configuration Source and CPU Operating Mode at Power-Up
System Security
PACSystems I/O System
Power-Up and Power-Down Sequences
Memory Protection
User program memory is read only.
User program memory is read only.
User program memory can be
written.
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