Servomex NanoTrace DF-760E, Instruction Manual

Page: 77 / 182

User Interface DF-760E 73
concentrations and will automatically shut the sensor off after 20 minutes at a level
greater than 20 ppm.
Figure 61: Oxygen Sensor Gas Valve Control Screen
NOTE: After the high oxygen level condition has been repaired the system will not
automatically turn the sensor back on. The user must access this screen and manually
turn the sensor back on after the problem has been solved. Similarly, if maintenance is
expected to bring about a high concentration of oxygen into the sensor lines, it is
advised to turn the oxygen sensor OFF.
NOTE: If there is a non-zero entry in the GSF setup screen for O2, then the
polarization voltage to the O2 sensor is automatically turned off and the O2 sensor is
automatically isolated from gas flow.
An alarm/relay combination may be assigned to the sensor on/off signal in order to
indicate the current status. See page 97 for additional information.
The state of the sensor polarizing voltage at the time of analyzer power up is
determined by parameters set on the Power-up defaults screen. See page 109 for
additional information on Power-up default settings.
Figure 62: Oxygen Sensor On/Off Control Screen
NOTE
The oxygen sensor is automatically turned off on initial analyzer
power-up from the factory. The user may change this setting with
the power up defaults screen.