Respironics ESPRIT Service Manual page 24

Chapter 3
Theory of Operation
3-10
The CPU interfaces with the pneumatics and displays through the main PCB
and daughter boards that are vertically mounted on the main PCB. The
daughter boards include the CPU PCB, digital PCB, analog PCB, VGA
controller PCB, and three stepper motor controller PCBs.
The digital control signals from the CPU are sent to the analog PCB where they
are converted into analog signals that control blower speed and chart recorder
outputs (pressure, flow, and volume). Analog data from the flow, pressure, and
oxygen sensors is conditioned and converted by the sensor PCB. The sensor
PCB conditions and coverts the data, and sends it to the analog PCB, where it
is read by the CPU.
Ventilator data from the CPU is conditioned by the VGA and man-machine
interface (MMI) PCBs, then displayed on an LCD.
The following table summarizes the electronic signal path for Esprit
components.
Component
100% O indicator
2
29 V Enable
Air (AV), oxygen (OV), exhalation
(EV) valves
Air (FS1), oxygen (FS2), exhalation
(FS3) flow sensors
Alarm High Indicator
Alarm Med/Low Indicator
Alarm Silence Indicator
Backlight (9.5-in. display)
Backlight (10.4-in. display)
Backup Alarm
Backup Battery, External Battery
Battery/Charging Indicator
Battery/In Use Indicator
Battery/Low Indicator
Blower DAC
Blower on/off
Blower temperature switch
Console: all keys
Esprit® Ventilator Service Manual © Respironics, Inc.
Signal Path Sequence
Front panel overlay, MMI PCB, main PCB, digital PCB, CPU
PCB
Main PCB, CPU PCB, power supply
Main PCB, motor controller PCB, CPU PCB
Sensor PCB, main PCB, analog PCB, CPU PCB
Front panel overlay, MMI PCB, main PCB, CPU PCB
Front panel overlay, MMI PCB, main PCB, CPU PCB
Front panel overlay, MMI PCB, main PCB, digital PCB, CPU
PCB
Backlight inverter PCB, MMI PCB, backlight control
potentiometer.
Backlight inverter PCB, DC/DC converter PCB, main PCB,
backlight control potentiometer
MMI PCB, main PCB, digital PCB, CPU PCB
Power supply
Front panel overlay, MMI PCB, power supply, main PCB,
CPU PCB
Front panel overlay, MMI PCB, main PCB, digital PCB, CPU
PCB
Front panel overlay, MMI PCB, digital PCB, CPU PCB
Blower controller PCB, sensor PCB, main PCB, analog PCB,
CPU PCB
Blower controller PCB, sensor PCB, main PCB, CPU PCB
Sensor PCB, main PCB, digital PCB, CPU PCB
Front panel overlay, MMI PCB, main PCB, CPU PCB
REF 580-1000-02 G