Theory of operation
Puritan Bennett™ 700 Series Ventilator System Service Manual
10070389 Rev. A
2-55
2.3.7 User interface (UI)
The UI includes the UI display PCB, keyboard, and knob encoder (see Figure 2-40).
The
UI display PCB
(Figure 2-41) includes three main sections: patient data, ventilator
settings, and ventilator status. LCDs (liquid crystal displays) and LEDs (light-emitting diodes)
on the PCB display data.
• A
4-line x 20-character LCD panel
(message window) (Figure 2-42) displays menus,
ventilator settings, and ventilator status information.
•
LCDs
(windows) provide 7-segment representations of either settings or monitoring data
(The 740 Ventilator has 12 LCDs, and the 760 Ventilator has 14 LCDs).
• There are three main categories of
LED
, as follows:
•
Bar graph LEDs
display airway pressure (740 and 760 Ventilators) and exhaled volume
(760 Ventilator only).
•
Key confirmation LEDs
display whether a key is selected and the type of breath delivered.
•
Ventilator status LEDs
are high-power indicators, which display the functional status of
the ventilator.
A membrane
keyboard assembly
(Figure 2-43) is attached to the UI PCB. Circuitry on the
controller PCB senses pressed keys. A software debounce routine protects against unintended
multiple keystrokes.
Extended data
Number of hours at various mean
pressure ranges
Recorded for these ranges: 0 to 9 cmH
2
O,
10 to 19 cmH
2
O, 20 to 29 cmH
2
O, 30 to
39 cmH
2
O, 40 to 49 cmH
2
O, and above
50 cmH
2
O.
Extended data
Oxygen solenoid data, including rise time
constant, on time constant, and offset
volume for high-flow oxygen solenoid;
time delay between opening solenoids
and retracting piston; on time constant
and offset volume for low-flow oxygen
solenoid.
Currently unused.
Extended data
Gains and offsets for various transducers
stored in EEPROM on pressure solenoid
PCB
Error logs
Alert log
Technical alerts and other conditions
detected during ongoing checks
Error logs
Test log
Conditions detected during calibration
tests, POST, SST, and EST (may also
contain some conditions recorded in the
alert log).
SST data
Whether individual tests were run,
whether a fault or incomplete was
overridden (by pressing MANUAL INSP),
the tests’ pass/fail status, overall pass/fail
status, time of most recent SST execution
EST data
10 most recently detected EST or SST
errors
Table 2-2: NVRAM contents (continued)
Type of data
Parameter
Notes
Summary of Contents for Puritan Bennett 700 Series
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