BIRD 428B-83H-01-C-110, Инструкция по установке и эксплуатации, Страница: 40 / 60

TX RX Systems Inc. Manual 7-9487-3 05/05/11 Page 32
BASE and TOWER software version can be read
from the display by using the ARROW buttons to
scroll down from the default display to the SOFT-
WARE VERSION sub-menu.
Front Panel LEDs
Status indicator LED’s for all the amplifiers illumi-
nate in one of two colors. The meaning of each
color is summarized in table 7. During normal oper-
ation, the LED’s for amplifier A and the BASE
amplifier (MCU system only) will glow green, indi-
cating normal current draw. The LED for amplifier
B will be off indicating this amplifier is in stand-by.
Form-C Contacts
The ALARM Form-C relay contacts are located at
the back of the control unit. These terminals are
intended for connection to the customer’s supervi-
sory and data acquisition system. Both normally
open and normally closed contacts are available.
There are two sets of terminals for customer con-
venience. Both sets of screw terminals operate in
tandem.
Figure 31 is a schematic representation
of the Form-C contacts functionality. Both sets of
contacts change state simultaneously in response
to a control signal from the CPU. The contacts are
shown in the drawing in the de-energized state.
When power is applied to the control unit the CPU
will energize the relays and the common terminals
will then be connected to the normally closed termi-
nals. This is the normal mode of operation. When
an alarm condition occurs the CPU will de-energize
the relays and the contacts will change state indi-
cating the alarm condition.
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 either of four distinct
conditions occur including an abnormal current
flow in any of the systems three amplifier assem-
blies or a loss of serial communications between
the base unit and the tower top box.
When the current to any of the three amplifiers
deviates from normal by approxi/- 55 ma
or greater the specific device LED will glow a solid
red. In addition, 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 provi-
sion for the amplifier in the control unit. The
ALARM Form-C contacts located at the back of the
unit will also change state.
Fault detection circuitry continuously monitors the
DC power operation of the primary tower top quad-
ALM NC
ALM NO
ALM COM
ALM NC
ALM NO
ALM COM
Alarm
Control
Signal
From
CPU
Relay
Coil
Relays shown when Control Unit
is in De-Engergized State
Relay
Coil
NOTE
Screw
Terminals
Figure 31: Schematic representation of the Form-C contact functions.