Section 2: Installation
Page 2-6
Instruction Manual 8144-DD/075020
Header
Position
H7
B Input Alarm Enable
A
If the 8144-DD is used with only an A clock input, connecting A
to B on header H7 disables the alarm inputs for the B clock
input. Loss of the A reference or the assertion of the A Alarm
input now results in a major alarm.
B
This is the normal connection using two clock input signals.
A Major Alarm exists when both references are not ready (AIS or LOS), or when
both external alarm inputs are asserted. A Minor Alarm exists when one of the
references is not ready (AIS or LOS), or when a single external alarm input is
asserted.
Header
Position
H8
Major Alarm Indicator Latch Select
A
The
MAJOR ALARM INDICATOR
on the front panel is
latched
on by a Major Alarm. A Major Alarm exists when both
references are not ready (AIS or LOS), or when both external
alarm inputs are asserted. The indicator is reset by the RESET
switch if either fault is no longer present.
B
The
MAJOR ALARM INDICATOR
on the front panel does
not
latch.
The indicator is ON only when a Major Alarm is present.
The light extinguishes automatically when the condition clears.
The RESET switch does not reset the indicator.
H9
Minor Alarm Indicator Latch Select
A
The
MINOR ALARM INDICATOR
on the front panel is
latched
on by a Minor Alarm. A Minor Alarm exists when one of the
references is not ready (AIS or LOS), or when a single alarm is
asserted. The indicator is reset by the RESET switch if the fault
is no longer present.
B
The
MINOR ALARM INDICATOR
on the front panel does
not
latch
. The indicator is ON only when a Minor Alarm is present.
The light extinguishes automatically when the condition clears.
The RESET switch does not reset the indicator.
H10
Major Alarm Relay Latch Select
A
The
MAJOR ALARM RELAY
is
latched
on by a Major Alarm. A
Major Alarm exists when both references are not ready (AIS or
LOS), or when both external alarms are asserted. The relay is
reset by the ACO switch, even though the fault may still be
present.
B The
MAJOR ALARM RELAY
does
not latch
. A remote indicator
shows only if the fault is present. The ACO switch does not
clear the MAJOR ALARM relay.
