Alicat VC Series Volumetric Flow Controller - Manual (Page 35)

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RS-232 Serial Communications is not responding.
Check that your meter is powered and connected properly. Be sure that the port on the computer to which
the meter is connected is active. Confirm that the port settings are correct per the RS-232 instructions
in this manual (Check the RS-232 communications select screen for current meter readings). Close
Hyperterminal® and reopen it. Reboot your PC.
Slower response than specified.
MC and VC Series Controllers feature a programmable Geometric Running Average (GRA). Depending
on the full scale range of the meter, it may have the GRA set to enhance the stability/readability of the
display, which would result in slower perceived response time. Please see “Pressure Averaging” and
“Flow Averaging” on page 17.
Jumps to zero at low flow.
MC and VC Series Controllers feature a programmable zero deadband. The factory setting is usually
0.5% of full scale. This can be adjusted between NONE and 3.2% of full scale. See page 17.
Discrepancies between old and new units.
Please see “Standard Gas Data Tables” explanation on page 30.
Maintenance and Recalibration
General: MC and VC Series Flow Controllers require minimal maintenance. They have no moving
parts. The single most important thing that affects the life and accuracy of these devices is the quality
of the gas being measured. The controller is designed to measure CLEAN, DRY, NON-CORROSIVE
gases. A 20 micron filter (50 micron for 50LPM and up) mounted upstream of the controller is highly
recommended. Moisture, oil, and other contaminants can affect the laminar flow elements and/or reduce
the area that is used to calculate the flow rate. This directly affects the accuracy.
Recalibration: The recommended period for recalibration is once every year. Providing that the CLEAN,
DRY, and NON-CORROSIVE mantra is observed, this periodic recalibration is sufficient. A label located
on the back of the meter lists the recalibration due date. The meter should be returned to the factory for
recalibration near the listed due date. Before calling to schedule a recalibration, please note the serial
number on the back of the meter. The Serial Number, Model Number, and Date of Manufacture are also
available on the Manufacture Data 2 display (page 16).
Cleaning: MC and VC Series Flow Controllers require no periodic cleaning. If necessary, the outside of
the controller can be cleaned with a soft dry rag. Avoid excess moisture or solvents.
For repairs, recalibrations, or recycling of this product, contact:
Alicat Scientific, Inc.
2045 N Forbes Blvd. Bldg.103
Tucson, Arizona 85745
USA
Ph. 520-290-6060
Fax 520-290-0109
email: [email protected]
Web site: www.alicatscientific.com