Valve Adjustment; Full Scale Flow Adjustment; 25% Flow Adjustment - Omega FMA 1500 User Manual

the transducer. The unit will now act as a mass flow meter.
CAUTION: If the valve is left in the AUTO (control) or OPEN mode for an
extended period of time, it may become warm or even hot to the touch.
Use care in avoiding direct contact with the valve during operation.
Follow steps outlined in section 7.2 and 7.3, then continue with step 7.4.2 below.

7.4.2 Valve Adjustment

Discontinue the PURGE mode (set valve for the closed position). Apply an inlet
pressure of 5 psig, and atmospheric pressure at the outlet. If a small flow occurs,
turn the set screw on top of the solenoid valve clockwise until the flow through the
FMA 1400 just stops.

7.4.3 Full Scale Flow Adjustment

Fully open the flow regulator upstream of the FMA 1400. Increase the inlet pres-
sure to 20 psig (25 psig for FMA 1400 units above 10 L/min). Apply a +5.00 VDC
set point reference. Using the calibrator check the flow rate. If necessary, adjust
R21 to match the desired full scale flow rate. [In control mode, turning R21 clock-
wise will decrease the flow. Conversely, turning R21 counterclockwise will
increase the flow through the FMA 1400.]

7.4.4 25% Flow Adjustment

Change the set point to 1.25 VDC to control at 25% 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 [R21], until the flow output is
correct.
7.4.5 50% Flow Adjustment
Change the set point 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 [R45], until the flow output is correct.
7.4.6 75% Flow Adjustment
Change the set point 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 [R44], until the flow output is correct.
7.4.7 100% Flow Adjustment
Change the set point 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 [R43], until the flow output is correct.
Repeat steps 7.4.4 to 7.4.7 at least once more.
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