Setup And Operation; Initial Setup - Instrutech CVM211 User Manual

Instruction Manual CVM211 Stinger

Setup and Operation

4
4.1

Initial Setup

Two of the most important steps for the initial setup of the gauge are to set zero and set span (atmosphere) as
described in the Programming section 4.3 below. This will ensure proper operation of the gauge and accurate
pressure measurements. 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 atmosphere 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 commonly 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 span
(atmosphere) with the gauge installed in your actual system. Please note the following:
Setting Zero (vacuum)
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Setting zero optimizes performance of the gauge when operating at a low pressure range of 1.33 x 10 mbar to
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1.33 x 10 mbar. If your minimum operating pressure is higher than 1.33 x 10 mbar, it is not normally
necessary to set zero and thus setting atmosphere should be adequate. If you are able to evacuate your system
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to below 1.33 x 10 mbar, it is always a good practice to check and set zero if necessary. See zero adjustment in
section 4.3
Setting Span (atmosphere)
Setting span (atmosphere) is the most important step for a newly installed 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 surrounding
the outside of your chamber. At sea level, this pressure is usually near 1.01 bar. At elevations above sea level,
the pressure 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 span adjustment in section 4.3
Note - Setting zero and atmosphere is normally required only once during the initial setup and maybe checked
by the user periodically. After power has been applied to the gauge during the initial setup, allow five minutes
for the gauge to stabilize (warm-up) before setting zero and atmosphere.
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