Alarm: High Drift / Unstable Oxygen Reading
Manufacturer: Yokogawa
Alarm Description
The High Drift alarm indicates unstable or continuously drifting oxygen readings that do not correlate with actual process conditions. This condition usually develops gradually and worsens over time if not corrected.
Typical Symptoms
- Oxygen value changes without process variation
- Large deviation between process and calibration gas
- Frequent recalibration required
- Unstable readings at constant load
Probable Causes (Most Common First)
- Sensor contamination (dust, ash, corrosion)
- Reference air leakage or blockage
- Process temperature instability
- Electrical noise or grounding issues
- End-of-life zirconia sensor
Field Checks
- Inspect probe tip for contamination
- Verify reference air flow and tubing condition
- Confirm stable temperature at probe location
- Check grounding and shielding
- Review drift trend history
Corrective Actions
- Clean probe or replace sensor
- Repair reference air system
- Improve probe mounting conditions
- Correct electrical interference
- Replace aging zirconia sensor
Impact on Measurement
High drift affects combustion efficiency, emissions compliance, and process control accuracy. Ignoring this alarm can result in fuel loss and unreliable analyzer data.