Aalborg GFM - Manual (Page 19)

7.3.4 10% Flow Adjustment
Using the flow regulator, adjust the flow rate to 10% of full scale flow according to the
calibrator. Check the flow rate indicated against the flow calibrator. Adjust the setting
for potentiometer [R33] by using the insulated screwdriver through the access win-
dow, until the output of the flow meter reads 0.5VDC ±63mV (or 5.6mA ±0.25mA).
7.3.5 25% Flow Adjustment (using R52 potentiometer)
Using the flow regulator, adjust the flow rate to 25% of full scale flow according to
the calibrator. Check the flow rate indicated against the flow calibrator. The output
of the flow meter should read 1.25VDC ±63mV (or 8.0mA ±0.25mA). If the reading
is outside of that range, place the jumper at [J1.A] as appropriate to increase or
decrease the signal. Adjust the setting for potentiometer [R52] by using the insu-
lated screwdriver through the access window, until reading is within specification.
7.3.6 50% Flow Adjustment
Using the flow regulator, increase the flow rate to 50% of full scale flow according
to the calibrator. Check the flow rate indicated against the flow calibrator. The out-
put of the flow meter should read 2.50VDC ±63mV (or 12mA ±0.25mA). If the read-
ing is outside of that range, place the jumper at [J1.B] as appropriate to increase
or decrease the signal. Adjust the setting for potentiometer [R38] by using the insu-
lated screwdriver through the access window, until reading is within specification.
7.3.7 75% Flow Adjustment
Using the flow regulator, increase the flow rate to 75% of full scale flow according
to calibrator. Check the flow rate indicated against the flow calibrator. The output of
the flow meter should read 3.75VDC ±63mV (or 16mA ±0.25mA). If the reading is
outside of that range, place the jumper at [J1.C] as appropriate to increase or
decrease the signal. Adjust the setting for potentiometer [R39] by using the insu-
lated screwdriver through the access window, until reading is within specification.
7.3.8 100% Flow Adjustment
Using the flow regulator, increase the flow rate to 100% of full scale flow accord-
ing to calibrator. Check the flow rate indicated against the flow calibrator. The out-
put of the flow meter should read 5.00VDC ±63mV (or 20mA ±0.25mA).
If the reading is outside of that range, place the jumper at [J1.D] as appropriate to
increase or decrease the signal. Adjust the setting for potentiometer [R40] by using the
insulated screwdriver through the access window, until reading is within specification.
Repeat steps 7.3.3 to 7.3.8 at least once more.
7.4 LCD Display Scaling
It may be desirable to re-scale the output reading on the LCD readout supplied
with certain model GFM transducers. Re-calibration for a new flow range or dif-
ferent engineering units are two examples of when this may be necessary.
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