40 tinb29e1-c (2019-10) VGC083A_B.om
Mini IG the turn on point for the IG when the 4 mA emission current has been
selected is fixed at 1.00E-03 Torr.
[Factory default = MANUAL MODE]
This function allows the user to choose the source of control for the IG. The IG can
be controlled from the Front Panel (MANUAL MODE), CG1, CG2 or the ALT
GAUGE (alternate gauge).
Select MANUAL MODE if you wish to use the front panel programming keys to turn
the ion gauge head filament to the on or off state.
Select CG1, CG2 or ALT GAUGE if the pressure measurement from CG1 or CG2
or the Alternate Gauge is to be used to automatically turn the ion gauge head
filament on and off.
CAUTION! Never use another gauge to automatically turn off the ion gauge
when the ion gauge filament in use is constructed of tungsten material (a coated
filament such as the yttria coated iridium version is okay). The response time of
other gauges may not allow for timely turn off of the tungsten filament leading to
possible filament damage. Always turn the IG filament OFF manually before pres-
sure is allowed to rise above 1.00E-03 Torr.
When CG1, CG2 or ALT GAUGE is selected in the IG CONTROL menu and the
ion gauge emission current is set to 100 μA, the ion gauge filament will turn on
when the pressure measured by CG1, CG2 or Alternate Gauge drops below the
value programmed in the IG TRIP PRES above. The ion gauge filament will turn off
when the pressure measured by CG1, CG2 or Alternate Gauge rises above the
value programmed for the IG TRIP PRES.
With BAG050 / 051 / 052 / 053 If the ion gauge emission current is set to 4 mA, the
ion gauge filament will turn on when the pressure measured by CG1, CG2 or Alter-
nate Gauge drops below 5.00E-04 Torr. The ion gauge filament will turn off when
the pressure measured by CG1, CG2 or Alternate Gauge rises above
5.00E-04 Torr. If the ion gauge emission current is set to 10 mA, the ion gauge
filament cannot be turned on using the pressure measurements from CG1, CG2 or
Alternate Gauge. However by selecting the AUTO IE 100-10 automatic menu
above, you would be able to use these devices to control the ion gauge and oper-
ate at the 10 mA emission current as well.
With BAG055 if the ion gauge emission current is set to 4 mA, the ion gauge fila-
ment will turn on when the pressure measured by CG1, CG2 or Alternate Gauge
drops below 1.00E-03 Torr. The ion gauge filament will turn off when the pressure
measured by CG1, CG2 or Alternate Gauge rises above 1.00E-03 Torr.
When CG1, CG2 or ALT GAUGE is selected in the IG CONTROL menu, the user
cannot turn on or turn off the IG filament manually using the IG ON/OFF soft-keys
of the front panel, RS232, RS485 or DIGITAL I/O signals. In this case the IG fila-
ment turn on or turn off is automatically controlled by CG1, CG2 or the Alternate
Gauge.
[Factory default = C0, C1, C2, C3, C4, C5 all factory-set to 50]
Do not change CAL FACTORS values. This menu is intended for future enhance-
ment of the VGC083A capabilities. Leave C0, C1, C2, C3, C4, and C5 CAL
FACTORS values at the factory default setting of 50. Changing these values to a
number other than 50 will result in inaccurate vacuum pressure measurements.
CAUTION! You must be aware of possible risks of inadvertently starting
emission (turning the IG filament to ON) when using an alternate gauge like a
capacitance diaphragm gauge as a source of control for turning the ion
gauge on and off. Failure to follow the recommended procedures for ensur-
ing that you do not inadvertently allow the ion gauge head filament to turn on
may result in equipment damage.
To minimize the risk associated with this using an alternate gauge to control
the ion gauge head filament, follow these recommended steps below
precisely:
1) Before selecting ALTERNATE GAUGE in the SETUP UNIT menu, the user
should turn off power to the VGC083.
2) Connect the alternate gauge to the VGC083.
CAL FACTORS
(VGC083A future use only)
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