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Restoring Default Values
Restoring default parameters provides a starting point for control unit re-adjustment in the
event pressure measurements become unreliable. To restore Terranova® 907 d
efault
parameters:
1.
Remove power from the control unit
2.
Simultaneously depress the
RAISE
and
LOWER
buttons while restoring power to
the control unit
3.
Release the buttons once the Self-Test has initiated
If reset process is successful, two BEEPs will be emitted and
t
he code RST will appear on the
unit display. Once the front panel buttons are released, the Self-Test will continue and the
Terranova® 907 will resume normal operation. Restoring default parameters does not exit
Pascal Mode.
Pressure Measurement
Terranova® 907 operation is almost automatic
and will commence after a successful S
elf-Test.
Pressure unit will auto range during use as system pressure increases or decreases.
Although
the control unit is able to simultaneously operate both types of pressure gauges, only one
pressure gauge reading will be output onto the display at a time. User can select between the
CEP / 275 and CDG pressure gauge via the
GAUGE SELECT
button to display the corresponding
pressure readings. The selected pressure gauge LED will illuminate during use.
Due to a number of system variables, pressure differences may result
with each subsequent pressure measurement and/or between
different pressure gauges.
Convection-enhanced Pirani Gauge
The Terranova® 907 may be set to output pressure readings based on either air / nitrogen or
argon. If gases other than air / nitrogen or argon are to be used,
Appendix 4
provides corrected
pressure values for a number of gases including helium with respect to air / nitrogen. For
example, if the vacuum system is backfilled with helium and the Terranova® 907 reads a
vacuum pressure of 13.2 Torr, true system pressure is approximately 5 Torr.
Unit display will read OFF if gauge cable is not connected. Unit display will read HI if system
pressure is greater than 995 Torr or if the pressure gauge is disconnected, but the gauge cable
is connected to the unit. Unit display will read LO if system pressure is less than the lowest
displayable value.
Display resolution is converted from torr to millibar or Pascal units. For
example, 20.0 mTorr will be converted to 26.7 µBar and 2.7 Pa, respectively.
Terranova® 907
pressure d
isplay resolution is as follows:
