Ulvac GI-M2, Инструкция по эксплуатации

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9.4.
ＤＥＧＡＳ
9.4.1. What is DEGAS?
"DEGAS" means dissociating the molecules adsorbed to the sensor head electrode, by
heat. By a model, there are two kinds of methods.
GI-M2
／
GI-D7
Molecules adsorbed to the sensor head electrode are released by heating.
GI-N8
This gauge uses the electron bombardment system for degassing. Electron
bombardment system releases the gas occluded to the grid by applying a high voltage of
700 to 500 volts and bombards the grid surface with thermions emitted from the filament.
9.4.2. Setting of DEGAS mode
The following two degassing modes are available.
①
Manual mode
A single press on the DEGAS switch turns ON degassing and a second press turns
OFF degassing. (DEGAS is active from the time when the DEGAS switch is
pressed to the time when it is pressed for a second time.)
②
Timer mode
A single press on the DEGAS switch turns ON degassing. It is automatically turned
OFF when an arbitrarily designated time elapses.
If it is desired to turn it OFF before the time elapses, press the DEGAS switch, and
degassing will be turned OFF.
9.4.3. Setting of timer mode
The time value in the timer mode is entered in the form of minutes.
Settable values are as follows.
01 to 99 [min]
When the input of an invalid value, the value is not updated. [
Ｅｒｒ
.
１２
] is
displayed on the segment indicator only in the front panel setting.
Inputs can be made from the front panel or through the communication (RS-232C).
The finally entered value is saved.
Pressing the [
⇒
(ENTER)] key on the front panel during automatic degassing will
display the remaining automatic degassing time.
9.4.4. Degassing movement conditon
GI-M2
／
GI-D7
Degassing is not active unless the filament is ON. Degassing is feasible as
long as the filament is ON even if the emission current is not normal, that is, [Em.
Valid NG].
Degassing is feasible in all measurable ranges, but if it is conducted in a high-
pressure region, the sensor head may be contaminated.
It is recommended to conduct degassing at a pressure of 10
-4
Pa (10
-6
Torr) or less.
GI-N8
Degassing is not active unless the filament is ON.
Pressure instructions value can work only in less than
１．３×１０
－４
Ｐａ
(
１．０×１０
－
6
Torr).
9.4.5. Degassing operation
Degassing operation can be entered from the front panel or the external I/O
connector or through the communication (RS-232C).
However, degassing from an external I/O connector is not active in the timer
mode even if it is set in the timer mode from the front panel or through the
communication (RS-232C) (manual operation in this case).