User's Manual

MODEL 2130 MARKER BEACON
Rev. A April, 2005 2-17
This document contains proprietary information and such information may not be disclosed to others for any
purposes without written permission from SELEX Sistemi Integrati Inc.
Addr = 89 Write Read
Bit 5 Reserved Reserved
Bit 6 Reserved Reserved
Bit 7 LOCPRN, LOCCLRN Reserved
2.3.3.2.4 Monitor Alarm Interface Circuitry
In order to insure that a monitor alarm signal is communicated to the control logic, redundancy is incorporated into the
monitor alarm signals. Each alarm signal is sent as two signals, one active high and the other active low. In the LCU,
resistors are used to pull each of their signals to their active (alarm) state. This insures that an alarm condition will be
sensed if there is an open in either alarm line. If an alarm line is shorted to its inactive (non-alarm) state, the other line will
communicate an alarm condition. If the 1_INT_ALARM+ signal is disconnected, a resistor in RN3 will pull the input high
resulting in an alarm condition being sent to the control logic in the EPLD U3. If the 1_INT_ALARM- signal is
disconnected, a resistor in RN15 will pull the input to a low logic level. The output of buffer U17 will send a low level
which will result in an alarm condition being sent to U22. HC logic devices are used to provide CMOS (mid rail)
thresholds for the alarm inputs.
2.3.3.2.5 Station Control Logic
The station control logic is duplicated in both U1 and U3. The logic responds to local operator control through the
pushbutton switch inputs as well as remote control through the parallel interface. The local operator can perform the
following functions:
a. Specify which Marker transmitter is to be designated as main.
b. Turn either transmitter ON and connect it to the antenna.
c. Turn either transmitter ON and connect it to the load.
d. Turn either transmitter OFF.
e. Toggle the bypass state of either of the monitored signal sources (Integral, Standby).
f. Silence the aural alarm (until the next event causes it to sound).
g. Toggle the state of local control. When local control is set, input from the keypad is enabled.
The following functions can be performed by the RMS through the parallel interface:
a. Functions a-g listed above.
b. Enable or disable the alarm signals from either one of the monitors. When a monitor's alarm signals are disabled, it is
functionally equivalent to the monitor producing constant alarms.
c. Set the "AND/OR" state of the alarm logic when it combines the alarm signals from Monitor 1 with the alarm signals
from Monitor 2. When set to "AND", both monitors must provide an alarm from the same source to cause the station
to transfer. When set to "OR", Monitor 1 signaling an alarm or Monitor 2 signaling an alarm will cause the station to
transfer.
d. Set the "Maintenance Alert" state. This lights the corresponding LED on the panel and sounds the aural alarm.
e. Set the "Remote Control Fault" state. This lights the corresponding LED on the panel and sounds the aural alarm.
In the alarm logic circuitry, the alarms from Monitor 1 alarm status are displayed on the panel. Similarly, the alarms from
Monitor 2 alarm status are displayed on the panel. If a given monitor’s alarm signals are disabled by the RMS, it is
equivalent to all of that monitor's alarm signals being asserted. The state of the AND/OR setting determines whether both
or either of the Monitor 1 or Monitor 2 signals are required to produce a transfer condition. If one of the two +12V power
fail logic signals from U10 goes active, the alarm logic will force an alarm condition for the monitor pair that is powered
from the corresponding +12V supply. In order to avoid shutting the Marker Beacon station down, the alarm logic is
forced to the AND state. This allows the other monitor to monitor the system.