TX RX Systems 434B-83H-01-M-110/48, Инструкция по установке и эксплуатации

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7;5;6\VWHPV,QF Manual 7-9547-1 12/09/14 Page 29
When power is applied to the base control unit the
CPU will energize the relay and the common termi-
nal will then be connected to the normally closed
terminal. This is the normal mode of operation.
When an alarm condition occurs the CPU will de-
energize the relay and the contacts will change
state indicating the alarm condition.
Figure 17
is a
schematic representation of the Form-C contacts
functionality. The contacts are shown in the draw-
ing in the de-energized state.
Specifications for the Form-C contacts are: Nomi-
nal switching capacity (resistive load) of 2 Amps @
30 VDC or 0.5 Amps @ 125 VAC, and Maximum
switching power (resistive load) of 60 Watts.
ALARMS
The system will alarm when an abnormal current
flows in any of the systems three amplifier assem-
blies. The specific devices front panel LED will
glow a solid red. The alarm Form-C contacts
located at the back of the unit will also change
state. In addition, a loss of serial communications
between the base unit and the tower top box will
cause both the A & B LED indicators to flash red.
Fault detection circuitry continuously monitors the
DC power operation of the primary tower top quad-
amplifier and automatically switches to the identical
secondary quad-amplifier if conditions indicate a
primary malfunction. When the current to any of
the amplifiers deviates from normal, amplifier
switching will take place in the tower top box if the
fault lies with one of the tower top amplifiers. There
is no switching provision for the amplifier in the
base control unit.
SYSTEM TROUBLESHOOTING
System problems fall under these main categories:
1) Performance problems characterized by poor
receiver sensitivity and possibly accompanied
by activation of the alarm system. RF interfer-
ence or component problems can be the cause.
2) Hardware problems.
3) Power Supply.
Performance Degradation
Most performance difficulties manifest as an inter-
mittent or continuous loss of effective receive chan-
nel sensitivity sometimes accompanied by audible
interference in FM systems or dropouts in digital
radios. Sensitivity loss on a continuous basis is
more likely to indicate a hardware problem which
may produce an alarm condition.
Table 7
is a trou-
bleshooting guide that is read from top to bottom to
narrow down the possible causes. The guide con-
tains both symptoms and suggested tests as out-
lined earlier in this manual. Both the measurement
of sensitivity and observation of the output spec-
trum are key tests along with the presence of any
alarm condition.
ALM NC
ALM NO
ALM COM
Alarm
Control
Signal
From
CPU
Relay
Coil
Relays shown when Control Unit
is in De-Engergized State
NOTE
Screw
Terminals
Figure 17:
Schematic representation of the Form-C contact functions.