In the drop down menu, click on record flow calibration.Make sure that the computer is recording from the iMic USB the recording levels should be set to 40.Demodulation should be used on the Airflow channel to be calibrated.In this case, channel Athe offset for Channel A should be set to adjustable and the knob set so that the yellow led light near the Nova is light,this precise setting is not importantClick on set zero, after a few seconds the record button will become activeThe yellow light shows that the signal level is in the proper range for recording.Pull out the plunger on the syringe until it reaches the 140 milliliter mark on the syringeYou are now ready to record a calibration signal, click on record and then promptly pressed down on the plunger to the bottom of its rangeThe movement down should be smooth and accomplished in roughly 1.5 seconds.The recording will stop automatically after five seconds.After the recording stops, click on close to close the record window.The calibration signal will appear on the screen bracket the calibration signal by left clicking before the signalAnd right clicking after the signalThe positions you click on are not criticalin the drop down menu. Now click on Calibrate Airflow.This will bring up a calibration menu with two entriestype in 0.14 litre. In the Top entry for the syringe volume.The mass calibration factor at the bottom depends on the mask to be used for a dual chamber maskIt is the number of screen rings in the chamber to be calibratedFor example type in four, our older hard walled single chamber mask has a calibration factor of 5.6 in the adult sizeNow click on calibrate at the bottom of the window.The airflow scale is now calibrated.