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Page 31
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Operation
D397-01-880 Issue E
4.8.10
Ion Gauge Controller (IGC) - gauge type displayed as ‘IONEB’
Note:
For a detailed specification and instructions regarding the use of the IGC refer to the instruction manual
(D048-40-880).
The Ion Gauge Controller is the only gauge compatible with a TIC where the gauge is not powered from the TIC. The
Ion Gauge Controller requires a (90-264 Vac) mains supply and has a separate electrode head. The TIC is used for
control and monitoring of the IGC.
The IGC and head is a gas dependent ionisation gauge system with a measuring range of around 5 x 10
-3
to 2 x 10
-11
mbar (3.75 x 10
-3
to 1.5 x 10
-11
Torr).
IGC has menu options in addition to those shown at the beginning of
.
Table 25 - Setup options IGC
Menu Option
Description
Degas
Allows the user to degas the gauge head. After an Ion gauge has been at atmosphere for some
time (for example during transit) or if the grid has become contaminated, it will be necessary
to degas the head to bake off the moisture and other contamination.
‘Scroll’ to ‘Degas’ and press ‘Select’.
‘Command Sent’ appears for 1 second to confirm degas sequence demanded.
Note:
If the IGC is off (no emission) the Degas demand will be ignored.
Degas is stopped either by a manual command or by timer in IGC (20-30 mins).
To stop Degas manually another Degas command should be sent.
The IGC provides actual degas status feedback. There are three possible degas states: off
(normal), on and inhibited. The IGC will inhibit degas if the pressure is too high and Degas will
resume once the pressure reduces. Degas status is displayed with gauge signal. If the gauge
display is voltage the units will change from ‘V’ to either ‘VDG’ or ‘VDI’ for either Degas or Degas
Inhibited. If the display is pressure the ‘x10’ part of the display will change to either DG or DI
(for Degas or Degas Inhibited). With a head sensitivity of 10/mbar the pressure should be below
2 x 10
-5
mbar to ensure degas will not be inhibited but it is recommended that Degas is not
initiated with pressures above 1 x 10
-6
mbar. During Degas pressure reading accuracy is reduced
as the head sensitivity is changed by the heating process.
Filament
Allows the user to select which of the two filaments ‘1’ (default) or ‘2’ are used. ‘Scroll’ to
‘Filament’ and press ‘Select’. ‘Scroll’ to change option and press ‘Select’ for change to occur.
Note:
You cannot change filament if the emission is on.
Head
Allows the user to select which of the two controller heads (sockets) ‘A’ (default) or ‘B’ is used.
‘Scroll’ to ‘Head’ and press ‘Select’. ‘Scroll’ to change option and press ‘Select’ for change to
occur.
Notes:
You cannot change head if the emission is on.
Emission
Allows the user to select the emission current. Options are ‘AUTO’ (default); 100 uA, 1 mA or
10 mA. If ‘AUTO’ is selected the TIC will automatically set the emission current based on the
gauge pressure. Changing emission current does not start emission.
The accuracy of the gauge can be optimised by selecting the filament emission current most
suited to the operating pressure range as shown in the following table:
Ion gauge
pressure
Emission current
Menu selection
> 1E-4
100
µ
A 100
UA
1E-8 to 1E-4
1 mA
1 MA
< 1E-8
10 mA
10 MA
‘Scroll’ to ‘Emission’ and press ‘Select’. ‘Scroll’ to change option and press ‘Select’ for change
to occur.
