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Doc. Ref. XGC-320-100119
V100 (2019-11)
4
Setup and Operation
4.1
Initial Setup
Two of the most important steps for the initial setup of the gauge
are to set zero (SET VAC) and set atmosphere (SET ATM) as
described in the Programming section 4.3 below. This will en-
sure proper operation of the gauge and accurate pressure meas-
urements. The gauge is calibrated at the factory using nitrogen.
Furthermore, the gauge is also installed in a certain orientation
when calibrated at the factory. Without setting zero and atmos-
phere after the gauge is installed in your system, the gauge may
not display the expected and correct pressures. This could be
caused by the fact that you may be using a different gas than
Nitrogen such as air to setup and calibrate the gauge (most com-
monly the case) and the gauge orientation is different than the
orientation used at the factory. As such, it is very important to
perform your own initial setup and calibration by setting zero and
atmosphere with the gauge installed in your actual system.
Please note the following:
Setting zero (SET VAC)
Setting atmosphere is the most important step for a newly in-
stalled gauge. If you prefer to use air to set atmosphere, vent
your vacuum system chamber to expose the gauge to the local
atmospheric pressure (air) and set atmosphere to match your
known local uncorrected barometric pressure (air). This is the
reading of ambient air pressure you will expect if you were to
vent and open your vacuum chamber to the atmosphere sur-
rounding the outside of your chamber. At sea level, this pressure
is usually near 760 Torr. At elevations above sea level, the pres-
sure decreases. Check your local aviation authority or airport
web sites or your current local weather conditions online to help
find your local uncorrected barometric pressure if you do not
have this information. See "SET ATM" in section 4.3