Aalborg GFC User Manual

Page 24

7.2.14

50% Flow Adjustment

Change the setpoint to 2.50 VDC to control at 50% of full scale flow. Check the
flow rate indicated against the flow calibrator. If the flow rate is not within ±0.75%
of full scale, re-adjust the setting for potentiometer [R38], until the flow output is
correct.

7.2.15

75% Flow Adjustment

Change the setpoint to 3.75 VDC to control at 75% of full scale flow. Check the
flow rate indicated against the flow calibrator. If the flow rate is not within ±0.75%
of full scale, re-adjust the setting for potentiometer [R39], until the flow output is
correct.

7.2.16

100% Flow Adjustment

Change the setpoint to 5.00 VDC to control at 100% of full scale flow. Check the
flow rate indicated against the flow calibrator. If the flow rate is not within ±0.75%
of full scale, re-adjust the setting for potentiometer [R40], until the flow output is
correct.

Repeat steps 7.2.13 to 7.2.16 at least once more.

TABLE II GFC SOLENOID VALVE ORIFICE SELECTION TABLE

7.2.17

LCD Display Scaling

It may be desirable to re-scale the output reading on the LCD readout supplied
with certain model GFC transducers. Re-calibration for a new flow range or dif-
ferent engineering units are two examples of when this may be necessary.

7.2.17.1

Access LCD Display Circuit

Carefully remove the LCD from the GFC or panel mounted surface. Remove the
aluminum housing on the side of the connection cable. Slide the LCD assembly
out of the aluminum housing.

ORIFICE PART NUMBER

FLOW RATE [N

]

OR.020

10 to 1000 sccm

OR.040

1 to 5 slpm

OR.055

5 to 10 slpm

OR.063

10 to 15 slpm

OR.094

20 to 50 slpm

OR.125

50 to 100 slpm