Intellipuff Service Manual
Page 20 of 51
Issue D 27/02/2014
EP59-12317
previous time in the data set is then defined as being the soft puff time and is
recorded.
The form will present a graph of the data set being currently collected of up to
8 puffs per timing. It will also present a table of the puff times used with the
minimum, maximum and average external puff pressures. The table will allow
the user to select a puff time for display on the graph. It will also indicate the
determined soft and hard puff times.
Once this process is successfully completed, the soft puff and hard puff times
are recorded for later loading into the EEPROM as entries S_Puff_Time and
H_Puff_Time in 38us units. On selection of the continue button the skew
timing and regression stage will be entered.
Pressure Calibration - Skew Timing and Regression
For the calculation of measured pressure from internal pressure readings, two
calibration stages are required; firstly external pressure reading is related to
mmHg units through calibrating the calibration ADC voltage against a known
pressure source and secondly relating internal pressure readings to external
pressure readings. The constants derived from the first calibration stage (ADC
to mmHg conversion) are stored in the hand piece EEPROM in both the unit
under test and the calibration unit in parallel. They will not however be used
by the hand piece software.
The skew and timing regression form relates the internal to external pressure
readings. At this stage both internal and external pressure are measured
