Instrutech The Hornet IGM402 User Manual page 32

Instruction Manual
- 100UA TRN ON [Factory default = 5.00E-02 TORR]
This allows the user to select a pressure value as measured by CG1 at which the IG filament can be turned
on. This is applicable only when the gauge is operating at 100 µA emission current setting and the IG CNTL
mode below is set to CG1 CONT IG. When operating with the 100 μA emission current setting, the 100UA
TRN ON pressure value can never be set higher than 5.00 x 10
Note - The user does not have the choice to select a turn on/off point to automatically switch the IG
filament state when the emission current selected is 4 mA. The IG filament turn off is always set to
-3
1.00 x 10 Torr when the emission current setting is 4 mA. When the 4 mA emission current setting is
selected the pressure must be at 1.00 x 10
- IG CNTL [Factory default = DIGI/RS485]
This allows the user to choose the source of control for the IG. The IG can be controlled via digital inputs,
RS485 commands, front panel soft-keys or
 DIGI/RS485
The DIGI/RS485 control selection allows the application of either digital inputs or RS485 serial
interface commands to operate the IGM402. The default state of the DIGI/RS485 selection is
digital input (DIGI). This control mode requires grounding pin 1 of the 9-pin D-sub male (DE-9P)
ANALOG connector to turn the IG filament to ON and activate the sensor.
The user should verify the DIGI/RS485 is selected in the IG CNTL submenu of the SETUP UNIT
menu. When operating in the Digital Input (DIGI) mode, the IG filament can only be turned on by
continuously connecting circuit ground (pin 2) to pin 1 of the DE-9P ANALOG connector. Degas
and emission current selection can also be set using the digital inputs available on the DE-9P
ANALOG connector. Connect the ANALOG connector pins 2 and 8 together to change from an
emission current of 100 μA to 4 mA. See
related to Digital I/O connections. Connecting ANALOG connector contact pin 6 to pin 2 will assert
DEGAS when the IG filament is in the ON state. An external control device like a PLC may be used
to set pin 1 to ground (circuit common) as long as the PLC circuit common (ground) is tied to the
IGM402 ANALOG connector pin 2.
To change from DIGI to RS485 communication mode, use the 9-pin RS485 D-sub female (DE-9S)
connector to connect the DATA A (-) and DATA B (+) RS485 signal lines. The user should verify
DIGI/RS485 is selected in the IG CNTL submenu of the SETUP UNIT menu.
In order for the IGM402 to operate in the in the RS485 mode, the user must send a command to
turn the IG to OFF. If you have already turned the IG ON in the default DIGI mode and you send
the IG OFF command via RS485 to auto switch from DIGI to RS485 mode, the IG will turn OFF. If
the RS485 command to turn IG ON is sent, then the IG will stay in the ON state and the control
mode will be auto switched to RS485.
The program code control logic is such that when switching from DIGI controls to RS485 controls,
the device will invoke a 'safe state' if any RS485 command is sent to switch from DIGI to RS485. A
InstruTech
-2
Torr.
-3
Torr or less before the IG filament can be turned on.
convection gauge CG1.
section 3.3.2.1, ANALOG connector pin-out for details
IGM402 Hornet
Page 30