Rockwell Automation T7150A Regent+Plus Communications Modules RS-232, RS-422 and RS-485 - Manual (Page 3)

Communications Modules (T7150A)
P D - 7 0 0 2 M a r - 0 6
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every millisecond to read characters from or write characters
to the communications module.
When the processor modules read characters from the
communications module, the communications module sends
characters through triplicated bus drivers to the processor
Safetybus. The processor modules vote this triplicated data
and perform communications processing. When the processor
modules write data to the communications module, the
triplicated data is voted by the communications modules and
sent to the dual UART where it is then transmitted out the
associated port.
The communications modules’ two serial ports operate
independently and can both be configured differently.
Electrical configuration is done by changing jumper settings
to select point-to-point or multidrop configurations. The ports
can be used to support a wide variety of functions including
Regent R2 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.
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. Communications message
format, framing, checksum, and other communications errors