O p e r a t i o n
5 - 2 7
SG 20 00 Ins tal la tion and O pera tion M anua l
M an ua l Con tro l B oa rd
The SG 2000 manual control board (SG2-MCB) serves to locally control redundancy functions and
ingress switch operation if a status monitor is not installed. Figure 3-2 illustrates the MCB board
mounted on the main RF board in place of the status monitor. Inputs to the MCB are the received
optical power signals from both the A and B receivers, scaled at 1 V/mW.
The MCB board contains two 3-gang, dual-in-line-package (DIP) switches and five screwdriver
adjustable potentiometers. Table 5-11 provides descriptions and functions of these user-interface
settings:
T a b l e 5 - 1 1
M C B u s e r - i n t e r f a c e s e t t i n g s
Desc ription
Functio n
Switch S1-1
Determines whether the primary/redundant reset state occurs at
0.5
dB
or
1.0 dB
more than the defined optical level threshold. This hysteresis or “gap”
prevents the automatic switch-over function from “hunting” or switching
back and forth if the received optical power remains close to the switching
threshold. The factory setting is 1.0 dB.
Switch S1-2
Enables selection of either normal (
NORM
) or manual override (
OVER
)
operation. In the
NORM
position, switchover between the primary and
secondary optical paths is automatically controlled by the received optical
power of the primary receiver. In the
OVER
position, the selection is
performed manually using switch S1-3. The factory setting is
NORM
.
Switch S1-3
Selects either receiver A (
RXA
) or receiver B (
RXB
) as the primary optical
receiver when S1-2 is in the
NORM
position. With S1-2 in the
OVER
position,
S1-3 manually enables either receiver. The factory setting is
RXA
.
Switch S2-1
Selects standard slaving or cross slaving of the transmitters to the
receivers. Set in the standard slaving (
STD
_
SLV
) position, with switch S1-2
in the
NORM
position, transmitter A follows the enable/disable status of
receiver A, and transmitter B that of receiver B. Setting S2-1 to cross
slaving (
CRS
_
SLV
) causes transmitter B to be on when receiver A is
enabled and transmitter A to be on when receiver B is enabled. The factory
setting is
STD
_
SLV
.
Switch S2-2
Controls the status of return transmitter A. If S1-2 is in the
OVER
position,
S2-2 either enables transmitter A (
TXA
_
EN
) or disables transmitter A
(
TXA
_
DIS
). If S1-2 is in the
NORM
position, then S2-2 enables slaving of the
transmitter status to the corresponding receiver (
TXA
_
DIS
) or overrides the
slaving function enabling the transmitter to be on continuously (
TXA
_
EN
).
The factory setting is
TXA
_
DIS
.
Switch S2-3
Performs the same function for transmitter B as S2-2 performs for
transmitter A. The factory setting is
TXB
_
DIS
.
Alarm potentiometer
(
ALRM
) sets the received optical power threshold at which automatic
switchover from the primary to the secondary path occurs. It can be set for
any power level up to 2.5 mW (+4 dBm). The factory setting is 0.25 V
(-3 dBm).
Содержание Starline SG 2000
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