400 SERIES INSTALLATION MANUAL
Page 4-7
190-00140-02
Rev
Q
4.4 MAIN
INDICATOR
4.4.1 Main Indicator Function
The Main Indicator displays both lateral and vertical deviation from selected course, To/From indications,
lateral and vertical flags and superflags.
The “CDI” key on the bezel of the GNS 430 takes the place of remote “NAV/GPS” switches, and is used
to toggle between display of GPS and VOR/ILS navigation display on a remote indicator. The Navigation
source is annunciated on the display above the ‘CDI’ key. The Navigation method is optionally
annunciated externally by connecting to the VLOC ANNUNCIATE output (P4001-1) and GPS
ANNUNCIATE output (P4001-2). GPS and VOR/ILS navigation may be toggled externally when the
CDI SOURCE SELECT input (P4001-73) is momentarily grounded. See section 4.5 for more information
on the external annunciators and switches.
An OBS resolver connection to the GPS is preferred, but not required. For the GNS 430, an OBS resolver
typically is connected to the MAIN OBS inputs for use with the GNS 430 VOR receiver.
4.4.2 Main Indicator Electrical Characteristics
4.4.2.1 Deviation
Pin Name
Connector
Pin
I/O
MAIN +LEFT
P4001
21
Out
MAIN +RIGHT (2.5V COMMON)
P4001
22
Out
MAIN +UP
P4001
27
Out
MAIN +DOWN (2.5V COMMON)
P4001
28
Out
The Deviation output is capable of driving up to three 1000
:
meter loads with
r
150 mV
DC
r
10% for full-
scale deflection. The drive circuit provides for more than full-scale deflection with a maximum course
deviation output voltage of ±300 mV
DC
r
10%
.
4.4.2.2 TO/FROM
Pin Name
Connector
Pin
I/O
MAIN +TO
P4001
25
Out
MAIN +FROM (2.5V COMMON)
P4001
26
Out
The To/From output is capable of driving up to three 200
:
meter loads. When indicating TO, MAIN +TO
is +190 ±40 mV
DC
with respect to MAIN +FROM. When indicating FROM, MAIN +TO is -190 ±40
mV
DC
with respect to MAIN +FROM. When invalid information is present (Flag IN VIEW) the
TO/FROM output is 0 ±10 mV
DC.
4.4.2.3 Flag
Pin Name
Connector
Pin
I/O
MAIN LFLAG
P4001
23
Out
MAIN LATERAL -FLAG (2.5V COMMON)
P4001
24
Out
MAIN VEFLAG
P4001
29
Out
MAIN VERTICAL -FLAG (2.5V COMMON)
P4001
30
Out
The Flag output is capable of driving up to three 1000
:
meter loads. When valid information is present
(Flag OUT OF VIEW) the Flag output is 375 ±80 mV
DC.
When invalid information is present (Flag IN
VIEW) the Flag output is 0 ±25 mV
DC.
Summary of Contents for GNC 420
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