12
before pressing the TARE button. If the unit reads a significant negative value
when removed from the line and blocked, it was given a false zero. It is better
to zero the unit at atmospheric pressure and a confirmed no flow condition
than to give it a false zero under line pressure.
Volumetric Flow Rate:
This parameter is located in the lower left of the display.
It is moved to the primary display by pushing the button below
CCM
in this
example. Your display may show a different unit of measure.
Mass Flow Rate:
The mass flow rate is the volumetric flow rate corrected to a
standard temperature and pressure (typically 14.696 psia and 25 °C).
This parameter is located in the lower middle of the display. It can be moved to
the primary display by pushing the button below
SCCM
in this example. Your
display may show a different unit of measure preceded by the letter
S
.
To get an accurate volumetric or mass flow rate, the gas being measured
must be selected. See Gas Select, page 14.
MENU:
Pressing
MENU
switches the screen to the
Select Menu
display.
Flashing Error Message:
An error message (
MOV
= mass overrange,
VOV
= volumetric overrange,
POV
= pressure overrange,
TOV
=
temperature overrange) flashes when a measured parameter exceeds
the range of the sensor. When any item flashes, neither the flashing
parameter nor the mass flow measurement is accurate. Reducing the value of
the flashing parameter to within specified limits will return the unit to normal
operation and accuracy.
If the unit does not return to normal operation contact
MATHESON
.
Summary of Contents for 819 Series
Page 46: ...46 Notes...
Page 47: ...Notes 47...
