Brooks Instrument 5882/92 - Manual (Page 21)

21
Installation and Operation Manual
X-TMF-FM-MFC-eng
PN 541-C-007-AAG
April, 2008
Flomega, Liquid MFC’s/MFM’s
3-2 Calibration Procedure
Note:
Calibration of the Flomega models requires the use of the digital voltmeter (DVM), and an accurate
calibration standard. It is recommended that calibration be performed only by trained and qualified service
personnel.
a. Install the Flomega in the flow calibration system. Apply power, open downstream shut-off valve,
apply line pressure, and set command voltage to 100%, or apply V.O.R.+ for some minutes. Allow
flow controller to purge with the calibration liquid for approximately 15 minutes.
b. Set command voltage to 0% and close downstream shutt-off valve. Allow the controller to warm up
for an additional 20 minutes.
c. Reference (REF) adjustment: Connect DVM Positive lead to pin REF and negative lead to the
Common. Adjust REF (P1) for 5 Vdc ± 1 mV.
d. Zero adjustment: Connect DVM positive lead to OUTPUT. Adjust zero for 0 mV ± 10 mV.
e. Command 100% flow. Wait 5 minutes.
f. With command at 100%, use the calibration standard to measure the mass flow rate. Adjust span
until the measured flow rate is within 0.5% of the desired flow rate.
g. Set command to 0% and close the downstream shut-off valve. Wait approximately 10 minutes for
the output signal to stabilize. Adjust zero for 0 mV ± 10 mV. Open downstream shut-off valve.
h. Command 50% flow. Wait 5 minutes and measure the flow rate with the calibration standard.
3-3 Response Adjustment
a. Make a step-in command to the controller from 2 to 100% of full scale flow and record the output
signal.
b. If the output signal shows more than 10% overshoot or oscillate; adjust proportional gain. If the
signal does not show overshoot, but is not within 2% of final value after the response specification;
adjust proportional gain the other way around.
c. Repeat steps a. and b. until the response output signal meets the specification.
3-4 Rangeability
The 5881/5882 is designed to control mass flows from 2 to 100% of the specified full scale flowrate.
This at an inlet pressure up to 100 or 400 bar (see pressure rating of your Flomega) and a maximal
differential pressure of 40 bar (5881: 20 bar).
Operation at other inlet or differential pressures is possible as long as certain guidelines are observed.
If a controller is operated with a process liquid other than its calibration liquid, a scale shift can occur
in the relationship between the output signal and the mass flowrate.
Section 3 Theory of Operation