Run/Stop Operations; Cpu Stop Modes - Emerson PACSystems RX3i User Manual

PACSystems™ RX3i and RSTi-EP CPU Reference Manual
GFK-2222AK
4.5

Run/Stop Operations

The PACSystems CPUs support four RUN/STOP Modes of operation. You can change
these modes in the following ways: the RUN/STOP Switch, configuration from the
programming software, LD function blocks, and system calls from C applications.
Switching to and from various modes can be restricted based on privilege levels, position
of the RUN/STOP Switch, passwords, etc.
Mode
Run/Outputs
Enabled
Run/Outputs
Disabled
Stop/IO Scan
Enabled
Stop/IO Scan
Disabled
Note: You cannot add to the size of %P and %L reference tables in RUN Mode unless the
%P and %L references are the first of their type in the block being stored or the block being
stored is a totally new block.
4.5.1

CPU STOP Modes

The CPU has four modes of operation while it is in STOP Mode. The two most common
are:
4.5.1.1 STOP-I/O Enabled Mode
I/O Scan Enabled - the Input and Output scans are performed each sweep.
CPU Operation
Operation
The CPU runs user programs and continually scans inputs and updates
physical outputs, including Genius and Ethernet outputs. The
Controller and Backplane Communications Windows are run in
Limited, Run-to-Completion, or Constant mode.
The CPU runs user programs and continually scans inputs, but updates
to physical outputs, including Genius and Field Control, are not
performed. Physical outputs are held in their configured default state
in this mode. The Controller and Backplane Communications
Windows are run in Limited, Run-to-Completion, or Constant mode.
The CPU does not run user programs, but the inputs and outputs are
scanned. The Controller and Backplane Communications Windows are
run in Run-to-Completion mode. The Background Window is limited
to 10ms.
The CPU does not run user programs, and the inputs and outputs are
not scanned. The Controller and Backplane Communications
Windows are run in a Run-to-Completion mode. The Background
Window is limited to 10ms.
Note: STOP Mode I/O scanning is always disabled for redundancy
CPUs.
Section 4
October 2019
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