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9.4.6.Instructions in DEGAS
GI-M2／GI-D7
The whole DEGAS movement operates a pressure measurement, too. There is the
case that pressure rise by DEGAS occurs by the state of the measurement head,
pressure at the movement. As a result, ON/OFF of the set point output varies with
it.When the pressure protection is activated, [
Ｅｒｒ. １3
] is displayed on the
front panel segment and it becomes OFF automaticaly.
GI-N8
Degassing is so programmed that full power is attained in about five minutes. The
filament may appear not lit immediately after degassing is actuated, but this is not a
trouble.
Pressure is not being measured during degassing. The filament protection circuit is
invalid. See to it that abrupt pressure rise does not occur during degassing
operation.The set point output is invalid (OFF) during degassing action.
The set point output is invalid (OFF) during degassing action.
With a glass tube, make sure the blue shield wire is connected to the S terminal of
the sensor head. The glass tube may be bored and vacuum may be broken.
Note that the glass tube wall will be heated to a high temperature (about 140°C in
the vicinity of filament) during degassing.
During degassing, the filament may be turned ON/OFF at intervals of several
seconds. At this time, discharge is taking place in the sensor head and the
protection of the degas control circuit is actuated at intervals of several seconds.
The ON/OFF intervals prolongs as the sensor head interior is cleaned and the
filament will stay lit as usual.
9.5. Filament Changeover
When the sensor head has two filaments, choose one either. When the sensor head
has one filament, set to the filament 1. The filaments can be changed over from the
front panel or external I/O connector or through the communication (RS-232C).
9.5.1. Filament changeover and external output
When the filament is changed over when the filament is ON, it will be OFF →ON.
As a result, indication・output will be in the initial state.
・Indication/BCD ： ０．００×１０
－
X
Ｐａ（Initial state）
・Analog output ： ０．００V
・Set point ： OFF
Change over the filament with the filament turned OFF, if possible.
9.5.2. Cautions in filament chageover
When the filament is changed over, the gas adsorbed to the filament and filament
stem will be released for some time after the filament has lit and the pressure will
rise temporarily.
The sensitivity of the sensor head depends on the distance between the filaments, grid
and ion collector electrode. The sensitivity differs slightly because the distance between
filaments 1 and 2 and the grid differs. As a result, the measured pressure output value
will also differ slightly (within the measurement accuracy).
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