GE Corometrics 250cx Series Service Manual page 50

Main Board PWA
2-22
Equipment Overview: Theory of Operation
The Main Board makes up the central processing unit for the 250cx Series Fetal
Monitor. The Main Board accepts simultaneously processed parameters directly
from four separate modules. The minimum configuration monitor has only the DSP
board as an input module. Heart rate (ultrasound and or FECG), uterine activity data,
mode information, and FMD data, flow from the DSP board to the Main Board via
DSP board FPGA shared memory. Maternal and fetal Oximetry makes up the
second and third modules. Information from these devices is passed to the Main
Board via RS-232 ports. The Main Board communicates with the front panel UI
keypad PWA using RS-232 interface, which is routed through the DSP board. The
Main Board PWA also provides a master reset for the UI keypad PWA. The Main
Board holds the NIBP control circuitry (minus pump and valves) and communicates
to it using a CMOS interface. The Main Board PWA connects to the Pneumatics
PWA which holds the NIBP pump, valves, and filter. The Main PWA contains three
external RS232 data ports for various external devices and setup/code update
functions. The Main Board PWA receives data from the rear panel options PWA to
allow the added Communication features. The Main board PWA formats all the data
and interfaces to the recorder PWA. The Main PWA also controls all of the audio
functions including generated tones to passing ultrasound audio from the ultrasound
PWA. The following sections show the block diagram of the 250cx Series Main
Board PWA and the data flow between the modules the Main Board.
Main Board Block Diagram
Following diagram shows the Main Board block diagram with internal and external
interfaces.
MAIN
REAR PANEL IINTERFACE
1. fast, rem mark
2. FECG 80db,MECG 60db
RECORDER
INTERFACE
To
1. data interface
Recorder
2. motor interface
Module
3. switch interface
Comm Bd int
1. J102 Interface
2. Keyboard Interface
To Comm Bd
MSpO Connector PWA
2
The MSpO Connector PWA receives the GEHC-IT universal SpO
2
on the front bezel of the 250cx Series monitor and transfers the analog signals on to
250cx Series Maternal/Fetal Monitor
2036947-001
TO ULTRASOUND BOARD
US1 US2
AUDIO MODULE
AUDIO MUX
+
D/A VOLUME AUDIO AMPLIFIER
CONTROLS
COMMUNCATION MODULE
CONTROL BLOCK
1. 68302 up 1. Rs232 Uart for ext SA02
2. rom+ram 2. RS232 Uart for ext NIBP
3. adrs dec, clock module, RTC 3. RS232 Uart for ext fsao2
4. Internal sao2 Uart
4. Control /status module
5. Internal Nibp Uart
5. Power-on reset module
6. Internal FSpO2 Uart
OPTIONS INTERFACE
DSP/front panel interface
1. 1k shared memory
2. Int input
3. reset output
4. Front panel Interface
To DSP/front panel interface
+
MIXER
patient cables
2
Revision C