Download iVPI, CAA Software Reference Guide

iVPI Application Rules
5.1.5.4
Double Break Output Board
Double Break Output boards (DBO type) contain eight outputs divided into two groups of
four outputs each. A GROUP data record is required to specify the positive and negative
supplies for each group. GROUP A contains the wiring for ports 1 through 4, and
GROUP B wiring supplies energy for ports 5 through 8.
DBO boards are logically grouped in pairs, via the slot number reference following the
words 'DBO BOARD' on the data record. They can be paired in an address group with
any other Vital output board type. In addition, there can be one unpaired Vital output
board per module.
Each output port used requires an I/O port data record to specify the symbolic name of
the output port and the wire names of the positive and negative wires that the port is
attached to through the plug coupler.
If the logical value of the absence-of-current-detecting (AOCD) check circuit is to be
used, another I/O port data record is required to provide the symbolic name of the AOCD
circuit. For double break outputs, the second port data record includes the number of the
port being referenced, and the option (CK) following the number. Each AOCD circuit to
be used must then be assigned a unique name, and it must differ from the name of the
output being checked.
The port numbers are assigned to the board from top to bottom, numbered 1 to 8.
NOTICE
If two boards are paired, the ports are still identified 1 to 8 for the first board and
1 to 8 for the second board.
Double break outputs can be driven steady or 'flashing'. The flash condition generates a
code rate of on for 1/2 second and off for 1/2 second. If any Vital output in a system is
required to flash, then all Vital outputs are susceptible to inadvertent flashing when they
are supposed to be on steady. In many cases a flashing lamp drive output may be a
more permissive aspect than a steady output, so there is a means to protect lamp drive
outputs (see the Lamp Drive Output Board Application Rules for details).
The rules for assigning flash options to double break outputs are identical to the rules for
single break output flash options.
P2512F, Rev. G, Aug/15
5-28
Alstom Signaling Inc.