Rockwell Automation T3122 ICS Regent Processor Modules - Manual (Page 4)

Processor Modules (T3110, 11, 12, 20, 21, and 22)
4
Industrial Control Services
while the I/O processors in each module read and write I/O
synchronously.
During these synchronous operations, all instructions and
data are distributed across the Safetybus where automatic
voting and fault detection occur.
Main Processor
During each scan cycle, the main processor executes
application programs, reading inputs from the shared RAM
and writing outputs to the shared RAM.
In addition to running application programs, the main
processor takes care of system overhead, such as:
• Background diagnostics including voter tests, read tests of
the EPROMs, and read-write tests of the RAM (this
automatic test is also what re-educates a new processor).
• Communications processing including reading from and
writing to the communications modules every one
millisecond and checking the communications messages at
the end of each scan.
• Fault filtering and reporting (which are available through
W INTERPRET ’s fault status and fault history features).
• Reading the communications module’s real-time clock (if a
real-time clock communications module is installed).
I/O Processor
During each scan cycle the I/O processor receives voted input
data into its local RAM and transfers it to the shared RAM —
making it available to the main processor. After being
processed by the main processor, output data are placed into
the shared RAM and read by the I/O processor into its local
RAM and written to the outputs.
The I/O processor also shares in managing system overhead.
This overhead includes:
• Background I/O processor tests (voter tests, read EPROM
tests, and read-write local RAM tests).
• I/O module tests (I/O module voter tests, logic loopback
tests, and coordinating other I/O module tests).