Nellcor N-180 Service Manual page 35

N-180 Pulse Oximeter Service Manual
LED PCB
Front Panel Controls
enable readings on SATURATION, RATE, BATTERY IN USE, LOW BATT,
PULSE SEARCH , NEONATAL and the pulse amplitude LEDS. The actual
segments that light on the respective LED élements depend upon the coding
of DRVO-7 at the time that an LED is enabled. Signals DRVO-7 come from the
CPU PCB VO controller as signals LED 0-7 (which feed processor device U23,
a driver).
The LED PCB (figure FO10-4) consists of LEDs that provide status
information,
BATT IN USE (LD1)
LOW BATT (LD2)
PULSE SEARCH (LD3)
NEONATAL (LD4)
HIGH SAT (LD13)
LOW SAT (LD14)
HIGH RATE (LD15)
LOW RATE (LD16)
AUDIO ALARM OFF (LD17)
'and operational information,
-* 'pulse amplitude (LD5 AND LD6)
* oxygen saturation (LD7, 8 AND 9)
* © pulse rate (LD10, 11, AND 12)
Pulse amplitude is represented by active segments of two light bar LEDs that
are stacked vertically. Each light bar has ten segments but only eight of the
. respective segments are used.
Oxygen saturation and pulse rate readings come from two banks of seven-
segment LEDs. These LEDs have green and red elements.
Controls are mounted on the front and rear panels of the monitor. Control
signals are found on the CPU PCB, the LED Drive PCB, and the front panel
membrane:
© © Alarm push button assembly
+ Control knob
* ON/STDBY switch
Alarm Push Button Assembly
The al. nbly has five membrane swi es anda
cable. The membrane switches and connecting cable are part of the monitor
. . front panel assembly.
Control Knob
The control knob connects to a sealed, two-phase rotary encoder mounted
behind the front panel. Encoder outputs are ROTSWA and ROTSWB, which
stands for phase A and phase B. The relationship of the phase A and phase B
output signals from the encoder, relates whether the knob is rotating
3-20