Theory of operation
2-62
10070389 Rev. A
Puritan Bennett™ 700 Series Ventilator System Service Manual
2.3.8.5 Air intake filter switch
The air intake filter switch determines whether the air intake filter is installed. (See
Figure 2-51 for air intake filer switch and Figure 2-47 for installation in ventilator). A tab on
the filter engages this microswitch, which is located in the air intake filter manifold. If the air
intake filter is not present, the AIR INTAKE ABSENT alarm is triggered.
Figure 2-51. Air intake filter switch
2.4 Communications option
The addition of the communications option adds serial port configuration and upload/
download enabling to the Service Menu. This applies to the 700 Series Ventilators with
software revision G or later. The communications option allows the ventilator to link to the
following devices:
• The 6217 Remote Alarm
• The Puritan Bennett™ EasyNeb Nebulizer
• A nurse call (or central station) device
• Up to two serial devices (such as a Puritan Bennett CliniVision System or other interactive
device).
2.5 Motor control and drive
The motor, which drives the piston back and forth, is controlled by the BD section of the
controller PCB, including the motor controller circuit. (See Figure 2-52). Motor driver power
circuits are on the BBU PCB.
Breath delivery parameters correspond to the following motor parameters:
•
Breath delivery phase
– Motor direction. Motor direction is sensed by the encoder.
•
Delivered volume
– Number of motor shaft rotations. Three rotations correspond to a
2.6 L volume displacement (or a 120 mm position displacement). Feedback from the
encoder is used to determine piston position. See Section 2.2.1.1 for a description of
encoder operation.
•
Patient pressure
– Motor torque. Applying the correct torque compensates for minor
leaks and maintains the baseline at the correct level. Feedback from the cylinder pressure
transducer helps maintain the cylinder pressure.
•
Flow
– Motor rotational velocity. The tachometer circuit on the pressure solenoid PCB
provides a backup for the motor controller chipset.
7-00164
Connect to normally open (NO)
and common terminals
Summary of Contents for Puritan Bennett 700 Series
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