Instrutech The Hornet IGM402 User Manual page 34

Instruction Manual
 CG1 CONT IG
This allows the use of the pressure measurement from CG1 to automatically turn the selected filament on
and off. Pin 1 of the ANALOG connector must be connected to Pin 2 of the ANALOG connector and
emission current must be set to 100 μA for this function to work. To operate the IG at an emission current
of 4 mA, see '2)' below. The filament will be turned on at the 100UA TRN ON setting when in the CG1
CONT IG mode. The on/off control of the IG filament using the pressure measured by CG1 can be set under
two different scenarios:
1) If the ion gauge emission current is set to 100 µA, the ion gauge filament will turn on when the pressure
measured from CG1 drops below the value programmed in the 100UA TRN ON submenu of the SETUP
UNIT menu. The ion gauge filament will turn off when the pressure measured from CG1 rises above the
pressure value programmed for the 100UA TRN ON setting.
2) If the ion gauge emission current is set to 4 mA, the ion gauge filament will turn on when the pressure
measured from CG1 drops below 1.00 x 10
pressure measured from CG1 rises above 1.00 x 10
Note - To turn the IG filament off manually when CG1 CONT IG is selected, pin 1 of the ANALOG
connector must be disconnected from pin 2 of the same connector. This is the case only when filament
turn off is required before the pressure measured by CG1 rises above the maximum of 5.00 x 10
for the 100 µA emission current setting and 1.00 x 10
highly recommended that PIN 1 of the Analog connector is wired in such a way that it can be connected
to pin 2 of the Analog connector, but that connection can be opened to manually turn off the IG. This
will allow the user to override the CG turning on the IG. Use of a manual switch which can be easily
accessed by the user should be considered. The IG will only turn OFF when the connection between
pins 1 and 2 of the ANALOG connector is open circuit and the main pressure display screen is active. If
the display screen is in one of the programming menus the manual switch is ignored and the IG will not
turn OFF even if the switch between pins 1 and 2 is open circuit.
When CG1 CONT IG is selected, the emission current and degas will operate using Digital Inputs as
described in the previous section (- IG CNTL, DIGI/RS485) as defined by the ANALOG connector pin-out
in section 3.3.2.1. For example, the default emission current setting for the IG when in the CG1 CONT IG
mode of operation is 100 μA. If it is desired to operate the IG with an emission current of 4 mA, then it
will be necessary to provide capability to switch the emission current select pin (ANALOG connector
contact 8) to power ground (circuit common) available at pin 2 of the ANALOG (DE-9P) connector of the
IGM402 while operating in the CG1 CNTL IG control mode.
InstruTech
-3
Torr. The ion gauge filament will turn off when the
-3
Torr.
-3
Torr for the 4 mA emission current setting. It is
IGM402 Hornet
-2
Torr
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