Using The Gauge With Different Gases; Effects Of Different Gas Types On Ionization Gauge Display - Instrutech The Hornet IGM402 User Manual

Instruction Manual IGM402 Hornet
7

Using the gauge with different gases

The IGM402 pressure display assumes that the pressure measurement device is reading nitrogen pressure. For
both convection and ionization type vacuum gauges, corrections must be applied to both the display and analog
outputs.
NOTICE
The following tables and text contain important information
regarding the use of ionization and convection gauges when measuring total
pressure of gas and gas mixtures other than Nitrogen / Air. For both types of
gauge transducers, corrections must be applied to both the displayed pressure
and the analog output to determine the true measured pressure. This is
particularly critical when using convection gauges to measure density of gases
other than N /Air.
2
CAUTION! Risk of over pressurizing a gas containment vessel and attached apparatus exists when using
pressure measurement devices that are calibrated for a specific gas type. Use a pressure relief device to
safely limit the internal pressure of a containment vessel to less than the maximum allowable working
pressure rating for the vacuum/pressure system and all devices attached to the system.

Effects of different gas types on ionization gauge display

7.1
Ion gauge pressure readings are calibrated for nitrogen. If you use a different species of gas or mixture of gases,
you will be required to either make manual corrections to the pressure readout or compensate the reading. The
Sensitivity adjustment function of the IGM402 you are using to measure the pressure of gas other than
nitrogen/air may be set to compensate the reading. Compensating the pressure reading using the Sensitivity
adjustment method may not be possible for certain gases if the sensitivity correction factor results in a
calculated sensitivity outside the adjustment range possible.
InstruTech
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