Rockwell Automation T3151 ICS Regent Real time Clock Communications Modules - Manual (Page 4)

Real-Time Clock Communications Modules (T3151)
4
Industrial Control Services
protocol, Modbus protocol, ASCII output, and Guarded Peer-
Link communications. The W
INTERPRET application is used
to configure the appropriate port functions and specify baud
rate, data format, parity, and node number.
Once each application program scan the processors modules
read the real-time clock data from the module. The real-time
clock information is placed on the Safetybus from three
independently controlled buffers, preventing failures in the
real-time clock communications module from propagating into
the system.
When the processor modules set the real-time clock, all real-
time clock communications modules that are installed in the
system are simultaneously set. After setting the real-time
clocks, the processor modules read real-time clock values from
the left-most installed communications module. If the left-
most real-time clock communications module is faulted, the
processor modules will then read real-time clock values from
the next real-time clock communications module to the right.
Testing and Diagnostics
The modules triplicated Safetybus interface ensures that no
failure in the module will effect the operation of the Regent
system or other module. Extensive fault detection and
annunciation of critical redundant circuits helps ensure that
processors will not accept erroneous data from a faulty
module.
Each type of communications module has a unique
identification code that is read by the controller. This code
lets the controller know what type of module is installed in
each communications slot. If a module is removed and
replaced with a module of a different type the processors will
indicate a COMM error.
The processor modules perform background diagnostic checks
on the module to test bus driver circuits and check the
communications module ID codes. Clock values are checked
for bad data. Communications message format, framing,
checksum, and other communications errors are checked by
the processor modules’ normal communications processing.