Mindray WATO EX-55Pro, Service Manual

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4. The second column is the zero point of the current sensor and the third column is the
zero point in case of factory calibration.
The following table lists the normal range of the zero point of A7 pressure and flow
sensors.
Sensor Normal Range of Zero Point (AD
Counts)
PAW sensor 7432 ~ 16206
PEEP pressure sensor 7432 ~ 16206
Inspiratory flow sensor 554 ~ 26457
Expiratory flow sensor 1392-19306
Internal flow sensor 1699-16768
The zero point A/D value of the PAW sensor and PEEP pressure sensor should fall
within the normal range of 7432 to 16206.
The zero point A/D value of the inspiratory flow sensor and expiratory flow sensor
should fall within the normal range of 554 to 26457.
The zero point A/D value of the internal flow sensor should fall within the normal range
of 1699 to 16768.
If there is a great deviation between the current zero point and the factory calibration
zero point, it indicates that the sensor is aging but it does not mean that normal
measurement cannot be performed.
If the current zero point exceeds the specified normal range, normal measurement is
affected and you need to calibrate the zero point again. If the zero point of the flow
sensor is not within normal range, replace the VCM.
NOTE

If the zero point of the pressure sensor is inaccurate in case of ventilation, the
baseline of the PAW waveform is not at the zero point and a great deviation exists
between pressure control and measurement.

If the zero point of the inspiratory/expiratory sensor is inaccurate in case of
ventilation, the baseline of the PAW waveform is not at the zero point and a great
deviation exists between TV control and measurement.

If the zero point A/D value of any sensor runs out of the normal range, it cannot be
corrected. Instead, the ventilator control board must be replaced.
4.14.2 Constant Flow Test (Checking the Flow Sensor
Accuracy)
NOTE

If a great deviation occurs on the measured Vt value, test the measurement
accuracy of flow sensors so as to determine whether another flow calibration is
necessary.

You can use any flowmeter with an accuracy of at least
±
2% for the accuracy
measurement of the flow sensors.