Atmospheric Technology
27
Appendix A
– Procedure for Pressure Transducer and Flowmeter Calibration
Flowmeter Calibration Procedure
1. Enter the
Manual
screen and without the pump running, observe the average
flow controller flow rate (the flow rate will oscillate). If it is not 0.00±0.02,
manually adjust the flow controller output by turning the "zero" adjust screw on
the side of the flow controller.
2. Go to the
Advanced
screen and enter 0.00 for the intercept for the channel
being calibrated.
3. Connect an accurate flowmeter (referenced to the desired temperature and
pressure) to the canister inlet for the channel of the flow controller being
calibrated.
4. Under
Manual
Mode, set the flow controller set point to its normally operating
value, open the channel solenoid valve, and turn on the pump. Read the
flowmeter value from the screen (X) after the flow has stabilized.
X:
5. Read the calibrated flow unit value (Y).
Y:
6. The slope is calculated by:
X
Y
Slope
Slope:
7. Go to the
Advanced
screen, enter the new value for the slope.
8. Go to the
Manual
screen and set the flow controller to the desired flow. Check
the “Calibrated Values” box and record the flow rate that is displayed in red. This
flow rate will be the calibrated flow rate with the applied calibration constants.