Self-tests
3-2
10070389 Rev. A
Puritan Bennett™ 700 Series Ventilator System Service Manual
3.2 Power-on self-test (POST)
This subsection describes POST, including its operation, routines, and error handling.
3.2.1 Structure of POST
POST diagnoses electronic problems using a minimal amount of system hardware. It is
composed of these three sections:
POST1
– Tests the breath delivery (BD) and user interface (UI) microcontrollers and
associated circuitry. Each microcontroller runs its own version of POST1. Both versions are
practically identical.
POST2
– Consists of tests specific to the BD and UI subsystems.
POST3
– Synchronizes both microcontrollers.
Each section of POST is in turn composed of various routines listed in Table 3-2. The tests
within POST are generally ordered so each one requires successively more operational
hardware than the last, permitting electronic components to be systematically tested.
3.2.2 Running POST
To run POST, turn on the ventilator power switch. A message appears, indicating POST is
running, the ventilator software revision, and the hours of use remaining before preventive
maintenance is required. At the end of POST (after approximately eight seconds), the last
valid settings are displayed. The appropriate indicator is lit to indicate the source of power to
the ventilator.
During POST, the ventilator’s safety valve is opened and the SAFETY VALVE OPEN light is
turned on. The safety valve is closed when breath delivery begins.
Extended self-
test (EST)
Lets a biomedical technician
thoroughly test the operational
integrity of the ventilator, both the
electronics and pneumatics. POST and
SST are part of EST.
•
When the ventilator is serviced
•
As part of the ventilator
performance verification
NOTE:
The performance verification, described in Chapter 5, is a more thorough
test of the ventilator to verify specifications are met. The technician runs a
partial or full performance verification after servicing the ventilator and at
regular intervals.
Ongoing
background
checks
These checks are performed so as not
to disrupt normal operation. Includes
these checks: reasonableness of analog
inputs, power supply, DC voltages,
pressure transducers, and more.
Automatically, continually, during
ventilation and a smaller number in
the standby mode
Table 3-1: Self-tests (continued)
Name
Purpose
When it is run
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