Siemens SC 7000 Service Manual page 26

Service Manual
Processor Section
Power Conversion Section
Front End Section
2.1 Front Bezel Board
2.2 Cooling System
2.3 Real Time Clock
2.4 Non-volatile Memory
Battery Backup and
Power Reset
10
The processor section contains all computer functions of the monitor. It
contains two MPC 860 processors, a VGA graphics controller, and a 2181
DSP. All of these devices communicate using one large FPGA (field
programmable gate array) that is downloaded at initialization. The FPGA
contains all custom circuitry used in the computer, including the processor
bridge, remote comm transmitter, pod com DMA, DSP interface, NBP
interface, and I/O interfaces for both processors. Configuration of the FPGA
may be updated with the Software through the memory card adapter.
The power conversion section operates on a DC input from +11 to +15
volts. It switches between the external supply, the external battery and the
internal battery for the proper power source, and generates all necessary
dc voltages for the unit. It charges and maintains the internal and external
battery. This section also contains the patient isolation for the two internal
front ends as well as two general pod comm ports. It also has the power
control for the NBP pneumatics.
The front end contains MultiMed and HemoMed circuitry. The MutiMed front
end provides the following parameters; 6-lead ECG, Respiration, Pulse
Oximetry, and Temperature. The NBP pressure transducer is also contained
in this front end. The front end is based on a single 16 bit oversampling
converter. Oversampling allows for a reduction in anti-aliasing analog
circuitry while maintaining superior noise rejection. The HemoMed front end
provides four invasive pressures and Thermal Dilution Cardiac Output.
The front bezel board is an interface board used to adapt a particular LCD
panel to the processor board. It also interfaces the front bezel rotary knob
and keypad to the processor. The front bezel board contains the backlight
invertor with a PWM input to allow for LCD brightness control in order to
save power.
The cooling system for the main monitor is convection based and uses a
patented chimney approach. The chimney is comprised of a heatsink which
cools the electronics and a plate which cools the LCD backlight. The
chimney is in the middle of the monitor and therefore is vented on top and
bottom. These vents should remain unobstructed for proper operation. The
chimney is waterproof and accidental liquid entering the chimney is safe.
CARE should be taken to operate the monitor below 45° C and store the
monitor below 60° C, since damage to the LCD can occur at 70° C. If the
internal temperature of the circuit board exceeds 80° C the monitor shuts
down to prevent damage to the electronics. The monitor does not restart
until the temperature is below the shut off value.
The Real Time Clock function is implemented with the EPSON-SEIKO
RTC4513 device, and is synchronized by the Central Station.
The shared RAM and real time clock are provided with a lithium battery
backup circuit to prevent corruption of this non-volatile memory during a
power loss condition (both primary and battery power are lost). Note that
the battery used for non-volatile memory backup should not be confused
with the internal and external batteries that are used to provide power to the
monitor base unit when primary power is lost. Non-volatile memory lithium
battery backup is controlled by a power supervisory device that provides a
power reset during a power loss condition.
Note: No provisions have been made to recharge this non-volatile
memory backup battery. Eventually (≈10 years), the battery must be
replaced.
Siemens Medical Systems, EM-PCS, Danvers
NOT A CONTROLLED DOCUMENT
SC 7000 and SC 9000XL Patient Monitors
ASK-T898-03-7600
7k9kXLTM.c2.CD_ROM.fm/04-99/kaupp