14
VII. PROBE QUALITY
Whenever the
Pachette 2
is initialized, a self-test is automatically performed that
checks the quality of the ultrasonic probe. Ultrasonic waves are emitted from the
piezoelectric element in the transducer housing and transmitted through the plastic
cone. A return signal (echo) is created when the ultrasonic waves pass through the end
of the plastic cone into free air. This echo signal is received by the piezoelectric
element, and then amplified and measured within the unit. The magnitude of the echo
signal is compared to the magnitude of the echo signal when the unit was originally
calibrated at the factory.
If the probe quality is satisfactory, the
Pachette 2
is ready to take measurements and
the operator is unaware that the self-test has occurred. However, if the probe quality is
not satisfactory, one of the following messages will be displayed on the front panel.
This message usually means the tip of the probe is wet. However, if drying the tip of
the probe fails to make this message go away, then the probe may have degraded to the
point that it will require replacement.
This message occurs when: (1) the probe connector is not mated or is improperly
mated to the connector on the front panel, or (2) the probe is defective.
CHECK
PROBE
PLUG IN
PROBE
PQF
FAILED
This message usually indicates a hardware failure occurred within the unit and the unit
must be returned for repair. See page 27 section X.E for service.