Operation Of A "Normal" A.C.U; Operation Of A "Backup" A.C.U - rcf RB 3300 Manual De Uso

• "Backup PA bus" line – This line is interconnected with all the A.C.U.s of a certain group, and is used for transmitting the signal coming
from the speaker output of a backup amplifier to the "NORMAL" unit of the group in order to drive the respective speaker line. When one
of the primary amplifiers of a certain group of A.C.U.s is disactivated, the speaker line that drove it is supplied by the "backup PA bus" li-
ne. The system therefore includes as many "backup PA bus" lines as there are groups of A.C.U.s. The line can be supplied directly by the
speaker output of the backup amplifier, or by means of a "BACKUP" A.C.U. when the backup amplifier is controlled by an RB 3300 board.
• "Monitor bus" line – This line is interconnected with all the A.C.U.s present in the system, and is used for transmitting the monitor signal
related to the speaker output of one of the amplifiers controlled by the A.C.U.s to the CP 3100 control unit so that the signal can be liste-
ned to using the monitor speaker on the control unit.

OPERATION OF A "NORMAL" A.C.U.

NORMAL UNIT SWITCHED ON
The points below described the operation of a "NORMAL" type A.C.U. when it is activated (ON); that is, when the primary amplifier under its
control is used for sound diffusion in a certain zone and is not replaced by the backup amplifier (where present) of its group.
a. The low level audio signal of the audio source (generally an output of the OB 3230 AUDIO OUTPUT boards of the switching matrix of the
system) drives the "M1" input of the "NORMAL" unit. This signal, after being regulated by the "ALC" function (when the LB 3340 DIGI-
TAL ALC board is installed), and processed by the "PA FAULT" and "LINE FAULT" functions (when the SB 3320 FAULT DETECTOR board
is installed), is directed to the "M4" output to drive the input of the primary amplifier being controlled.
b. The "M6" and "M7" terminals are connected with each other, and the "audio bus" line passes through the "NORMAL" unit without being
interrupted. Therefore, any other "NORMAL" units of the group connected upstream from this line with respect to the backup amplifier
have the possibility to supply the "audio bus" line with the low level signal of the source to which they are connected (generally an out-
put of the OB 3230 AUDIO OUTPUT board).
c. The "M8" and "M9" terminals are connected with each other, and the "backup PA bus" line passes through the "NORMAL" unit without
being interrupted. Therefore, any other "NORMAL" units of the group connected upstream from this line with respect to the backup am-
plifier have the possibility to receive the signal for speakers coming from the backup amplifier in order to supply the speaker line to whi-
ch they are connected.
d. The "M10" and "M11" terminals are connected with each other, and the output of the primary amplifier controlled by the A.C.U. supplies
the speaker line.
NORMAL UNIT OFF
The points below describe the operation of a "NORMAL" type A.C.U. when it is disactivated (OFF); that is, when the primary amplifier under
its control is not used for sound diffusion in a certain zone and is replaced by the backup amplifier (where present) of its group.
a. The "M6" and "M7" terminals are not connected with each other, and the "audio bus" line is interrupted: any other "NORMAL" units of
the group connected upstream from this line with respect to the backup amplifier no longer have the possibility to supply the "audio bus"
line with the low level signal of the audio source to which the line is connected (generally an output of the OB 3230 AUDIO OUTPUT board
of the switching matrix of the system). Consequently, the units cannot be substituted.
b. The "M1" and "M7" terminals are connected with each other, and the audio signal coming from the audio source (generally an output of
the OB 3230 AUDIO OUTPUT board) supplies the "audio bus" line.
c. The "audio bus" line drives the input of the backup amplifier with the audio signal of the source connected to the disactivated "NOR-
MAL" unit. If the backup amplifier is also controlled by an RB 3300 back-amplifier board, the "audio bus" line will drive the "M1" input of
the "BACKUP" unit.
d. The "M10" and "M11" terminals are not connected with each other, and the speaker output of the primary amplifier controlled by the
"NORMAL" unit no longer supplies the respective speaker line.
e. The "M8" and "M9" terminals are not connected with each other, and the "backup PA bus" line is interrupted. Any other "NORMAL" units
of the group connected upstream from this line with respect to the backup amplifier no longer have the possibility to receive the signal for
speakers coming from the backup amplifier to supply the speaker line to which they are connected. Consequently, the units cannot be
substituted.
f. The "M9" and "M10" terminals are connected with each other, and the audio signal transmitted by the "backup PA bus" line coming from
the speaker output of the backup amplifier, or from the "M10" output of the "BACKUP" A.C.U. (where present), supplies the speaker line
that was previously connected with the primary amplifier that has been replaced.

OPERATION OF A "BACKUP" A.C.U.

BACKUP UNIT ON
The following points describe the operation of a "BACKUP" A.C.U. when it is activated (ON); that is, when the backup amplifier under its con-
trol is used to replace a primary amplifier belonging to the same group.
a. The low level audio signal transmitted by the "audio bus" line, coming from the "NORMAL" unit that controls the primary amplifier re-
placed, is applied to the "M1" input of the "BACKUP" unit. This signal is directed to the "M4" output to drive the input of the backup am-
plifier.
b. The "M10" and "M11" terminals are connected with each other, and the speaker output of the backup amplifier supplies the "backup PA
bus" line, which results in being connected with the speaker line of the primary amplifier replaced.
BACKUP UNIT OFF
The following points describe the operation of a "BACKUP" A.C.U. when it is disactivated (OFF); that is, when the backup amplifier under its
control is not used for sound diffusion in a certain zone.
a. The "M1" and "M7" terminals are connected with each other, and any signal coming from a disactivated "NORMAL" unit and transmitted
by the "audio bus" line drives the input of the next backup amplifier. If the next backup amplifier is also controlled by an RB 3300 back-
amplifier board, any audio signal transmitted by the "audio bus" line will drive the "M1" input of the next "BACKUP" unit.
b. The "M10" and "M11" terminals are not connected with each other, and the speaker output of the backup amplifier controlled by the unit
does not supply the "backup PA bus" line.
c. The "M9" and "M10" terminals are connected with each other, and any audio signal coming from the speaker output of the next backup
amplifier, or from the "M10" output of the next "BACKUP" unit, supplies the "backup PA bus" line. If there is a disactivated "NORMAL"
unit, this line is then connected with the speaker line of the primary amplifier replaced.
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