GE Corometrics 250cx Series, Руководство по обслуживанию

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Revision C 250cx Series Maternal/Fetal Monitor 2-23
2036947-001
Equipment Overview: Theory of Operation
the internal SpO
2
cable that in turn connects to the SpO
2
Carrier PWA. The MSpO
2
connector PWA keeps the sensitive analog SpO
2
signals shielded on the inner layers
of the board. R1 and R2 are 0 Ohm resistors that are used to provide a means of
disconnecting the shorts between pins 4 and 9 and pins 8 and 11 if needed. The
shorts are present to provide Ohmeda connectivity on these no-connect pins on the
universal connector. All the signals entering this PWA are patient isolated and
signals leaving this PWA though the MSpO
2
cable are also isolated. See side view
of assembly below.
SpO
2
Carrier PWA
The SpO
2
Carrier PWA holds the MSpO
2
module. It receives MSpO
2
patient cable
connections from the universal front-end connector PWA and internal cable on its
isolated side and routes them to the connected Nellcor MP-506 or NELL-3, Ohmeda
TruSignal, or Masimo MS-11 modules. It supplies isolated power to the SpO
2
modules and transfers the isolated data generated by the modules using opto-
couplers to the front-end motherboard on to the 250cx Series system for processing.
The 250cx Series system is able to reset the maternal and the SpO
2
modules using
opto-coupled reset lines.
Keypad PWA
The keypad PWA is made up of two front panel PWAs, main and volume/alarm.
The main UI keypad has two functions, one for input controls and a second for the
recorder chart light feature. This PWA contains most of the front panel buttons
except for the volume and alarm cancel buttons and receives input from the trim
knob control. The keypad is of the elastomeric type and utilizes backlight LEDs to
light each key. This PWA also receives the volume/alarm keypad PWA inputs
through an external cable, processes all key closures, and communicates to the main
processor key status. In addition the main PWA receives data from the main
processor (routed through DSP PWA) and controls the recorder-on led. The volume/
alarm PWA contains the volume and alarm key buttons and outputs to the main
keypad PWA button status. It also is of the elastomeric type and has backlight LEDs
for each key. The main PWA interface with the main board is through an RS-232
interface.
FECG/UA PWA
The FECG/UA PWA is made up of two separate isolated patient front-ends, FECG
and Uterine pressure. The FECG front-end converts the low level signals received
from the fetus through the spiral electrode to electrical impulses which are
amplified, filtered, and sent across an isolation barrier. The un-isolated FECG signal
then is further amplified and sent off the FECG PWA, routed by the front-end
motherboard to the DSP PWA, where it is digitized and processed. In addition to
this the FECG mode line (Cable plugged in sense line) from the ECG connector is
MSpO
2
front
panel connector
2 x 5 internal
cable header
MSpO
2
internal cable