B. Peripherals
(Ref. Fig. 016)
(1) Digital data inputs The ISIS indicator receives digital data inputs from the following components:
(a) Inertial Reference Two ARINC 429 high-speed buses provide the ISIS indicator with the optional magnetic heading indication (label 320). In normal configuration, the parameters displayed on the ISIS indicator come from the ADIRU 1. When a failure is detected, switching on the ADIRU 3 has to be performed manually through the ATT/HDG selector switch on the SWITCHING panel.
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ISIS - Interfaces
Figure 016
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(b)
ILS 1 (or MMR 1) One ARINC 429 low-speed bus provides the ISIS indicator with the LS function (label 173 for LOC and label 174 for G/S).
(c)
A fourth ARINC 429 input (low or high speed) is reserved as system provision.
(2) Discrete Inputs The ISIS indicator receives the following discrete inputs:
(a)
Ground/open signal from the ATT/HDG selector switch for selection of active ADIRU 1 or 3.
(b)
Ref baro pressure in in.Hg and hPa pin-program
-this discrete input permits the display of the reference barometric pressure in in.Hg in addition to the reference barometric pressure in hPa.
(c)
Altitude in meter pin-program
-this discrete permits the display of the altitude value in meters in addition to the altitude value in feet.
(d)
V-bars optional function pin-program
-this discrete permits to change the basic A/C symbol by the V-bars symbol.
(e)
Test discrete input
-this discrete input allows the ISIS indicator to manage the BITE failures sent to the CFDIU.
(f)
Four input discretes are used for indicator face tilting The face of the ISIS indicator can be set at 0 deg. and tilted from 10 to 24 deg. by steps of 1 deg.
(g)
One discrete input is used as parity. (Ref. Fig. 017) The parity control includes the monitoring of the optional function pin-programs and the ISIS indicator face tilt discretes. The parity discrete is activated only if the sum of the wired discretes is an even result. The parity discrete is monitored during power-up tests and continuous built-in test. If the parity is valid, it is memorized into non volatile memory. If the parity is not valid, the last memorized configuration is used and the white MAINT flag is displayed in the left top part of the display area (when CAS < 50 kts) until the configuration is valid.
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ISIS Indicator - MAINT Flag Display
Figure 017
R 1EFF : 106-149, 213-213, 221-299, 301-399, 1 34-22-00Page 24 1401-499, 1Config-2 Aug 01/05 1 1 1CES 1 If the ATT 10s message appears when the MAINT flag is shown, the message has priority. The flag is displayed again as soon as the message disappears.
(3)
Digital data output The ISIS indicator provides the following outputs:
(a)
Centralised Fault Display Interface Unit (CFDIU) The ISIS indicator is connected to the CFDIU to transmit the following words:
-LRU identification, Part Number (P/N) and Serial Number (S/N) (label 354),
-Built-In Test (BITE) status (label 356),
-Unit code (label 377).
(b)
ARINC 429 output bus (low speed) for the following air data:
-barometric corrected altitude in feet (label 204) and in meters if corresponding option is activated (label 214),
-standard altitude in feet (label 203) and in meters if corresponding option is activated (label 216),
-altitude rate (label 212),
-computed airspeed in knots (label 206),
-total pressure in hPa (label 242),
-uncorrected average static pressure in hPa (label 245),
-Mach number (label 205),
-barometric reference setting in hPa (label 234) and in in.Hg if corresponding option is activated (label 235).
(c)
ARINC 429 output bus (high speed) for the following inertial data:
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