Aalborg AFC - Manual (Page 14)

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5.3 Swamping Condition
If a flow of more than 10% above the maximum flow rate of the Mass Flow Meter
is taking place, a condition known as "swamping" may occur. Readings of a
"swamped" meter cannot be assumed to be either accurate or linear. Flow must
be restored to below 110% of maximum meter range. Once flow rates are lowered
to within calibrated range, the swamping condition will end. Operation of the meter
above 110% of maximum calibrated flow may increase recovery time.
5.4 Set Point Reference Signal (AFC)
AFC flow controllers have a built-in solenoid valve and allow the user to set the
flow to any desired flow rate within the range of the particular model installed. This
valve is normally closed when no power is applied.
The set point input responds to an analog 0 to 5 VDC reference voltage. This volt-
age is a linear representation of 0 to 100% of the full scale mass flow rate.
Response time to set point changes are 1 second (AFC 26) and 2 seconds
(AFC 36/46) to within 2% of the final flow over 25 to 100% of full scale.
On pin 6 of the AFC transducer is a regulated and constant +5VDC output signal.
This signal may be used in conjunction with a local set point potentiometer for flow
setting.
FIGURE 5-1, LOCAL SET POINT POTENTIOMETER CONNECTIONS