GE Datex-Ohmeda Aisys Carestation Reference Manual page 41

The Power Controller board produces other voltages.
• The 28 VDC that is generated by the U-Frame comes on the Power Controller board and is used to charge the machine
batteries in one of three (3) modes. The charge voltage varies depending on the condition of the batteries.
• The 28 VDC is regulated down to +12 VDC, +12.5 VDC and 3.3 VDC.
• The 12 VDC and 3.3 VDC remain local on the Power Controller board and are used by on-board circuits and the on-
board processor.
• The +12.5 VDC, created by the circuit (Brick) under the large heat sink, is a high current output. It supplies power to
subsystems remote from the Power Controller board (Display Unit and Anesthesia Control board).
• Fan 1 and Fan 2 are capable of running at one of two speeds (high and low). They are controlled by the Power
Controller board's microcontroller as it monitors temperature by circuitry also on the Power Controller board.
There are four conditions the Power Controller board can be placed into:
OFF
1. : System unplugged from AC Mains or the AC Mains Circuit Breaker open and the On/Standby Switch in the
Standby position.
• In this condition, the Power Controller board is truly OFF. This is indicated by No Fans and No illuminated LEDs.
There is no Battery Charging.
Standby
2. : The system is plugged into AC Mains and Mains Circuit Breaker closed (receiving 28 VDC from U-Frame
Power Supply) and the system switch in the Standby position.
• In this condition, 180 VAC is sent to the U-Frame Power Supply, which converts it to approximately 28 VDC and
sends a signal "AC_GOOD" to the Power Controller board (along with the 28 VDC). A "green" AC Mains LED on the
front panel of the machine will illuminate because of this signal.
• Even though the On/Standby Switch is in the Standby position, the Power Controller board will receive the 28 VDC
and create from it a +12 VDC, a battery charge voltage, and a +3.3 VDC (for microprocessor, ROM, RAM, etc).
• The microprocessor will run its Boot Code. During this brief time, the CPU LED may be dimly lit (or fast flashing).
Soon it will begin flashing at a 2 Hz rate (indicating it is running application program). Almost immediately, the fans
should turn on. One or more of the battery status LEDs should illuminate and the battery connected LED should
also illuminate. The XMIT LED will remain OFF (indicating no communication to the Display Unit). The RCV LED will
be on solid (indicating no communication to the Display Unit).
ON
3. : system is plugged into AC Mains and Mains Circuit Breaker closed (receiving 28 VDC from U-Frame Power
Supply) and the system switch in the ON position.
• The movement of the System Switch to the ON position will trigger the CPU (via On/Standby Logic circuitry) to
enable the +12.5 V DC/DC Brick to send +12.5 VDC to the Display Unit and the Anesthesia Control Board. Notice
a 12.5v LED under connector J4 (Anesthesia Control Board connector) illuminates solid. Within approximately one
minute, the XMIT and RCV LED's will be mostly off but will briefly and randomly flash indicating communication with
the Display Unit.
• Recap LED Status: CPU flashing at 2 Hz rate, XMIT/RCV flash randomly, 12.5v constant illuminated, BATTery
CONNected constantly illuminated, battery status LEDs illuminated depending on the battery condition.
ON Batteries ONLY
4. (no AC mains)
and the On/Standby Switch in the On position. The system will switch to battery operation for up to 30 minutes (with
AM Monitor backup, longer if not connected to AM Monitor).
• There should be no interruption of operation and the "green" AC Mains LED on the front panel of the machine will
NOT be illuminated. The LEDs that indicate battery condition will turn off (this may not happen immediately).
M1046983 04/08
: The system is NOT plugged into AC Mains or the Mains Circuit Breaker is Open
2 Theory of Operation
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