Install Manual

Preliminary
SKY899
Installation Manual
2-26
Rev. A
Synchro (XYZ) heading connections:
HEADING_X P1-46 (Synchro X)
HEADING_Y P1-47 (Synchro Y)
HEADING_Z P1-48 (Synchro Z)
HEADING_H P1-49 (26 V ac High)
HEADING_C P1-50 (26 V ac Low)
HEADING_FLG P1-51 (Heading Valid)
2.13.2 AHRS (Attitude Heading and Reference System)
AHRS provides aircraft attitude and heading values via the ARINC-429 bus. ARINC-429 receiver channel
speed can be 12.5 or 100 kHz and must be paired with another input device set to the same speed. Refer to
paragraph 2.9 for ARINC-429 receiver channel information.
2.14 LAMP OUTPUTS (ABV and BLW)
The lamp outputs are used only with an alternate display that is not capable of annunciating the vertical
display modes for above (ABV) and below (BLW). Outputs are switched to ground when active. The lamps
require a separate dc source (constant or dimming circuit). If lamp voltage is an ac source then an isolation
relay must be used.
Lamp connections:
LP1OUT P1-66 (ABV)
LP2OUT P1-85 (BLW)
Depending on the vertical display mode selected the appropriate annunciator(s) will light. If in normal
mode neither lamp will light, if in above mode the ABV lamp will light, if in below mode the BLW lamp
will light, and when unrestricted vertical mode is selected both lamps will light. See figure 2-7.
ABV BLW
(Above)
ABV BLW
(Below)
ABV BLW
(Normal)
ABV BLW
(Unrestricted)
Figure 2-7. Above and Below External Lamps
2.15 OPERATIONAL MODE OUTPUT (optional)
Operational mode output can drive a lamp annunciating when the system is in operational mode (i.e., not
in standby mode). Output is switched to ground when system is in operation mode. The maximum current
draw is 300 mA. The lamp requires a separate dc source (constant or dimming circuit). If lamp voltage is
an ac source then an isolation relay must be used.
Operational mode connection:
OPER_MODE P1-31
2.16 POWER INPUT
The SKY899 is a 28 V dc system (18 to 32 V dc) and requires a 5A circuit breaker. See paragraph 2.6.5 for
cable and shield connection information.