Typical Alarm Categories
- Sample Conditioning – moisture, liquid carryover, filter blockage, drain issues
- Pressure / Flow – regulator hunting, restrictions, leaks, low supply pressure
- Temperature / Stability – cabinet or internal temperature deviation
- Calculation / Quality – unstable output, invalid inputs, incorrect CV/Wobbe calculation
- Communication / Output – Modbus/OPC issues, scaling, mapping, quality/status mismatch
Most Common Field Causes
- Liquid carryover → sudden jumps or incorrect Wobbe values
- Moisture / dewpoint problems → unstable or drifting output
- Pressure hunting → fluctuating Wobbe/CV
- DCS scaling errors → analyzer looks correct locally but wrong in control room
Calibration Notes
- Calibrate only after sample, pressure, and temperature are stable
- Do not calibrate while conditioning or pressure alarms are active
- After calibration, confirm trend stability over time, not a single value
- Always verify DCS scaling and quality flags post-calibration
Field Best Practices
- Fix sampling and pressure issues before touching calculation or outputs
- After maintenance, allow sufficient stabilization time
- Compare to lab results only after analyzer stability is confirmed
Rule of thumb: 90% of Wobbe alarms originate from the sample system,
not the analyzer electronics.