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6.
Explanation of Menu Items and Navigation
6.1
Measurement
6.1.1
The measurement screen contains the reading of the sensor in easy-to-read blue digits and
includes units. In addition to the digital reading, the yellow bar on the measurement screen
provides an analog indication of the pressure based on a logarithmic scale. At 1*10
−
3
Torr the
yellow bar should stretch across the width of the screen. At 1*10
−
8
Torr the yellow bar will
disappear, and at 5*10
−
5
Torr, the yellow bar will be approximately half way across the screen.
6.1.2
The sensor high voltage must be turned on to display a reading. If the high voltage is not on, the
measurement screen will display "OFF". When the high voltage is toggled on, the unit will display
"Starting" until the unit has reached a steady measurement. Once a steady measurement is
obtained, it will be displayed. If the unit goes into overcurrent protection mode, the display will
read "Over". If Pin Control is enabled, the unit will attempt to start every 60 seconds. If
overcurrent protection mode continues upon an attempted start, the unit will continue to read
"Over". If Menu Control is enabled, the unit will display "OFF" and the high voltage will need to
be turned on again. See Section 4.3 for more details. If the high voltage is enabled and the
pressure is below 1*10
−
8
Torr, then the unit will display "Low" to indicate that the pressure is
below the measurable limit.
6.2
High Voltage Toggle
6.2.1
If the unit is in Menu Control Mode, then the user must turn on the high voltage by sending a
command over communications or by navigating to the High Voltage Toggle menu screen. Once
at the High Voltage Toggle screen, press ENT to unlock the screen, press UP or DOWN to change
the setting, and then press ENT to save the change. The high voltage will then turn on and a
pressure indication will be displayed on the Measurement Screen. If the pressure is too high, the
unit will go into overcurrent protection mode and the high voltage will turn off. To restart the
unit once a safe pressure has been achieved at the gauge, simply repeat the steps to turn on the
high voltage
6.3
System Settings
6.3.1
The system settings menu contains the ability to change the measurement units, apply a gas
correction factor, change the digital resolution to display an extra digit, and set the Vsense
Control method for the unit. There is also a diagnostic screen for use by Televac® service
representatives to troubleshoot the unit.
6.3.1.1
To modify the system settings
6.3.1.2
Navigate to the measurement screen.
6.3.1.3
Press SEL twice.
6.3.1.4
Press UP and DOWN arrows to navigate between panes under the system settings
heading.
6.3.1.5
Press ENT to unlock the specific screen. ADJ will appear at the top of screen to show
that the unit is unlocked and that a change can be made.
6.3.1.6
Press UP or DOWN to select between the options available.
6.3.1.7
Press ENT to save the changes or SEL to navigate away without saving. ADJ will
disappear from the screen after either ENT or SEL has been pressed.
6.3.2
Units
6.3.2.1
The MX7B has three selectable units to choose from: Torr, mbar, and kPa. When
changing units, all of the relevant settings previously saved in the unit will be converted
to the appropriate units.