Teledyne 3290 - OEM percent oxygen analyzer - Manual (Page 36)

Operation Model 3290
Teledyne Analytical Instruments 26
4.4.2 LO Alarm
Setting the LO Alarm sets the concentration BELOW which the LO
alarm will activate. To set the LO Alarm:
1. Press the
SET LO ALARM
function button once.
2. Immediately press either the  or  button to raise or lower the
displayed value, as required, until the display reads the desired
percent concentration.
4.4.3 Sensor Fail Alarm
The SENSOR FAIL alarm is factory preset in the instrument
software at 0.05%. It cannot be changed by the user. It is a low O
2
alarm and triggers when the O
2
level is below this level of 0.05% O
2
.
Teledyne incorporates a low O
2
alarm to indicate sensor failure,
since for a percent O
2
sensor, the most common failure mode is
depletion of the lead anode over time and O
2
exposure, which results in
a zero or near zero signal from the sensor.
Should this alarm trigger, the ALARM Indicator below the SET
function buttons will blink, and the alarm relay contact dedicated to this
function will change state.
4.5 Selecting a Fixed Range or Autoranging
The Model 3290 can operate in fixed high, fixed low, or
autoranging mode. To change modes:
1. Press and then release the
SET HI RANGE
and the
SET LO
RANGE
buttons simultaneously.
2. Immediately (within 5 seconds) press either the  or  button
until Auto, Lo, or Hi displays on the LCD, as desired.
After about three seconds, the analyzer resumes monitoring in the
selected range mode.
4.6 Calibration
Preliminary—If not already done: Power up the Analyzer and allow
the LED reading to stabilize. Set the Alarm setpoints and the analysis
ranges to the desired values.