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VOR (2)
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Map (2)
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Plan.
The switch inputs permit automatic switch over of the PFD (outboard) to the ND (inboard) location in case of a PFD failure. The switch inputs also permit a ND in two locations.
The graphics generator receives the PFD and ND reformatted
data from the PFD and ND generators. It converts this data to a
video format and sends it to the DUs through a coaxial cable.
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PRIMARY DISPLAY SYSTEM -DU FUNCTIONAL DESCRIPTION
General
Each display unit (DU) receives this from the AIMS cabinets:
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Graphics data
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Display format commands.
AIMS data goes to the DUs through coaxial cables. The DUs also receive brightness control data from internal and external sources. The DUs use this data to show flight information and status data to the flight crews during normal and non-normal conditions.
The input/output (I/O) controller also gets DU address information from five identification pins.
Input/Output Controller
The I/O controller receives, converts, and transmits data to the AIMS cabinet and the DU functions. The I/O controller sends graphics data to the beamformer and brightness control data to brightness control circuit. It sends command and BITE data to the DU controller.
A ground on an identification pin is a logic one. Address numbers on each DU set the standard configuration.
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DU Controller
The DU controller uses a dedicated bus to receive and send data to the I/O controller. The DU controller is a programmable logic device. The DU controller has built in test (BITE) and fault logic circuits. BITE and fault circuits collect status data from the functions in the DU. The DU controller formats the data and sends it to the I/O controller. The DU controller also sends a DU reset signal and processes the DU identification (ID).
Beamformer
The beamformer receives the digital data and changes it to a CRT-like image. The beamformer splits the image data and sends it to the liquid crystal display (LCD). The beamformer also responds to BITE.
LCD Interface Register and LCD
The LCD interface register changes the two data images from the beamformer into a single image and loads the values into the LCD source drivers. The LCD interface register applies voltages to compensate for data that changes. This improves LCD response times. The interface also supplies timing and control signals to the LCD drivers. The LCD circuit responds to BITE.
Brightness Control
The brightness control circuit responds to the BITE. It uses a combination of these inputs to adjust the LCD brightness:
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PRIMARY DISPLAY SYSTEM -DU FUNCTIONAL DESCRIPTION
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Bezel light sensor (BLS), internal
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Paired DUs, WXR, and RLS from the brightness controls and sensors table, external.
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PRIMARY DISPLAY SYSTEM -DISPLAY CONTROL FUNCTIONAL DESCRIPTION
General
There are four display channels in the primary display system. Each channel has a graphics generator, a coax coupler, and six coax cables.
Each AIMS cabinet has a left (M010) and a right (M011) graphics generator (GG). During normal operation, three of the GGs each send data to two DUs. The fourth GG is a spare. The GGs normally drive the displays at a 20 Hz rate.
Display control (DSPL CTRL) switches on the left instrument source select panel (L ISSP), center display control panel (CDCP), and right instrument source select panel (R ISSP) change the source of display data for the six display units (DUs).
Each switch has two positions, AUTO and alternate (ALTN). Normally, the switches are in the AUTO position. With the switches in the AUTO position, the AIMS cabinets automatically switch sources when a GG fails.
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