Although the Transonic Flowprobes are factory calibrated, there is still a need to calibrate the probe with the PowerLab Data Acquisition System. This is accomplished using Units conversion in LabChart.
Follow the steps below to calibrate a Perivascular Flowprobe in LabChart.
1. First prepare the Flowprobe using TEST MODE
2. The next step is to observe the Flowmeters signal indicator. The Signal Quality Indicator should show a 5 bar signal although 3 bars are acceptable.
3. Start recording in LabChart.
a. Press the Mode button to change the mode to Zero and the analog needle will deflect back to 0 Volts. This will output a 0V signal into LabChart.
b. Next, press the Mode button to change the mode to Scale and the display will indicate the volts-to-flow conversion for the probe. This is used to calibrate the system for use with the PowerLab. The analog meter will change to 1V, and the analog output will read 1V. This will send a 1V signal to the PowerLab. The flowmeter will provide accurate flow measurements up to 5x the scale factor of the active probe.
c. Press the Mode button once more to switch to Measure Mode in order to observe the measured flow in the system.
4. Stop recording in LabChart.
5. Highlight the 0V and 1V data.
6. Go into the channel menu for the flow channel and choose Units Conversion
7. Highlight a portion of the 0V area of the data, assign this to Point One (see image below) and enter 0 in the block to the right. Highlight a portion of the 1V area of the data, assign this to Point Two (see image below) and enter the maximum flow rate the probe is calibrated for in the block to the right. (The max flow rate can be seen in
Scale mode).
9. Assign the appropriate units (mL/min or L/min)
10. Select OK
NOTE: If the flow is inverted once recording begins, use the Invert button on the front panel of the Flowmeter to invert the signal and correct the flow.