GE Centiva/5 Plus, Technical Reference Manual

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2 Theory of operation
TRM, Centiva/5 Plus, M1047448/CM-922026, rev. 3.50.a of 11/05 2-9
On board power supply micro A
Input
Output
Safety
Microprocessor A
Graphic display
The control panel supply voltage with +13V/15V is delivered from the main engine
to the panel supply fuse (SI 1), the inverter supply fuse (SI 2) and the alarm supply
fuse (SI 4).
From SI 1 the +13V/15V (EA P08) is supplied to the +5V supply (EA P01), the 5.0V
reference (EA P03) and the alarm LED’s (EA S20). Beyond the fuse SI 3, the 5 V bus
EA P02 is distributed to the micro A (EA S00), the DCU Graphics board (EA S12),
the VGA display (EA S13), the buttons (EA S15) and the Com wheel (EA S16).
From SI 2 the +13V/15V is supplied to the back light inverter (EA S11), that
supplies the Display back lights (EA S10).
From SI 4 the +13V/15V is supplied to the alarm horn system (EA S05).
The interface components ComWheel (EA S16) and buttons (EA S15) talk to micro
A directly. Data input from micro B is received via the internal serial port (EA S01).
The alarm horn control (EA S06) talks to micro A.
Micro A controls output signals to the alarm LED’s (EA S20), the audible alarm (EA
S05) the back light inverter (EA S11) and the VGA display via the graphic DCU
board (EA S12). Data output to micro B is made via the internal serial port (EA
S01).
Micro A talks to the watchdog system (EA S02) on PC board B, enabling micro B to
react in case of a malfunction of micro A. The watchdog has access to the audible
alarm too.
The micro A handles all data to display in the screen, as well as audible and visual
alarm indicators within the control panel. The A EPROM is loaded with the language
specific issues. The A EEPROM allows storing a “shadow” data set. Disconnection
of the control panel during operation will cause the watchdog system to activate
and micro B to shut down the system.
Graphic display of data in the VGA screen (EA 9) is performed via a DCU graphic
board (EA 8).