Alicat MC Series Mass Flow Controller User Manual
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Meter does not agree with another meter I have in line.
Volumetric meters are affected by pressure drops. Volumetric flow meters
should not be compared to mass flow meters. Mass flow meters can be
compared against one another provided there are no leaks between the two
meters and they are set to the same standard temperature and pressure. Both
meters must also be calibrated (or set) for the gas being measured. M Series
mass flow meters are normally set to Standard Temperature and Pressure
conditions of 25 ° C and 14.696 psia. Note: it is possible to special order meters
with a customer specified set of standard conditions. The calibration sheet
provided with each meter lists its standard conditions.
When performing this comparison it is best to use the smallest transition
possible between the two devices. Using small transitions will minimize lag and
dead volume.
RS-232 / RS-485 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 / RS-485 communications select screen for current meter readings).
Close Hyperterminal® and reopen it. Reboot your PC. See pages 10, 11 and 30
for more information on RS-232 / RS-485 signals and communications.
Slower response than specified.
MC-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 24.
Jumps to zero at low flow.
MC-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 24.
Discrepancies between old and new units.
Please see “Standard Gas Data Tables” explanation on page 37.