User's Manual

Model 1150A DVOR
2-46 Rev. - November, 2008
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.
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.
e. Set the “Remote Control Fault” state. This lights the corresponding LED on the panel.
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 +48V power fail logic signals goes active, the alarm logic will force an alarm condition for the monitor pair
that is powered from the corresponding +48V supply. In order to avoid shutting the VOR station down, the alarm
logic is forced to the AND state. This allows the other monitor to monitor the system.
The alarm signals from the monitors have already been given the appropriate transfer delay times within the
monitors. This results in an immediate transfer when the combinatorial requirements of the alarm signals are met.
When a transfer condition occurs, the present transmitter that is connected to the antenna system is taken off the air.
The other transmitter is connected to the antenna system, and turned on (if it is not already on). If the transmitter,
not designated as main connected to the antenna system when the transfer condition occurs, the control logic will
enter the shutdown state and both transmitters are turned off. Once the control logic enters the shutdown state, no
further transfer operations will take place until a local operator or the RMS turns one of the transmitters on and
specifies that it is connected to the antenna system. The Station Control Logic controls which transmitter is
connected to the antenna system by the status of the +24V ANT outputs.
2.3.2.14.1.14
System Configuration Inputs
In order to reduce the amount of effort required to program various modules within the VOR for the proper
configuration, there are eight logic signals that are sent from the RMS to each module to specify the system
configuration.
2.3.2.15
Test Generator (1A3A5) CCA Theory
Test generator CCA performs two functions. The primary function is to provide a standard reference signal to the
DVOR monitors for calibration whenever directed by the RMS CPU for monitor integrity testing. The secondary
function is an operator maintenance function, which is to allow test signals to be sent to the monitor(s), as directed
by an operator through the PMDT. The operator can vary signal parameters (i.e., frequency, percent modulation,
phase shift, etc.) to determine if a monitor is functioning properly and will alarm at the required settings.
2.3.2.15.1
Test Generator CCA Block Diagram Theory
Refer to Figure 2-18. The Test Generator CCA primary purposes are to generate test waveforms for verification of
the Monitor CCAs as well as control of audio recording/play-back.
System1 and System2 +48VDC supplies from connector P2 are diode-OR’d and fused before routing to a +5VDC
DC-DC converter. The +5VDC output is linearly regulated to +3.3VDC as well as switched to -5VDC by another
DC-DC converter.
Each of the aforementioned output voltages is range-monitored by window comparators. The wired-OR’d outputs of
the window comparators assert a power-OK signal and light an LED when all output voltages are within the
tolerance windows. The power-OK signal eventually routes to the Facilities CCA for PMDT reporting.