MKS HPS 947 Series, Руководство по эксплуатации и обслуживанию, Страница: 29 / 40

23
HPS
®
Products Series 947 CEP System
3. Locate the point at which a vertical line from the He or Ar curve intercepts
the pressure axis. This point corresponds to the true pressure for He or Ar.
The nitrogen equivalent pressures of some gases can exceed the
measuring capabilities of the Series 947 CEP Controller. For
example, a true pressure of 20.0 Torr of helium is equivalent to a
nitrogen equivalent pressure of several 1000 Torr. The Series 947
CEP Controller is not capable of measuring this pressure of
helium.
Calibrating for Other Gases
To determine the voltage/pressure relationship for gases which are not shown
in the graph or table, you might need to calibrate the Series 947 CEP System
with this gas. This calibration requires a gas-independent sensor, such as a
capacitance manometer, to act as a standard. A curve like that of page 17
can then be generated and used as described above.
The Series 947 CEP Controller is not intended to be calibrated
for direct pressure readings of gases other than air or nitrogen.
The calibration is intended
only to match the air/nitrogen curve
of the Controller to the characteristic of a particular sensor.