Analyzer Reliability vs Accuracy – What Really Matters?
In analyzer datasheets, accuracy gets the spotlight. In real plants, reliability decides everything.
Engineers often debate analyzer accuracy in decimals and percentages. Technicians, however, face a different reality: an analyzer that is perfectly accurate but frequently unavailable is practically useless.
An accurate analyzer that is down gives zero value. A reliable analyzer gives usable information every day.
What Is Accuracy?
Accuracy refers to how close a measurement is to the true value. It is usually defined under ideal laboratory conditions.
- Clean samples
- Stable temperature
- Controlled pressure
- Perfect calibration gases
These conditions rarely exist in operating plants.
What Is Reliability?
Reliability is the analyzer’s ability to:
- Stay online
- Provide consistent trends
- Recover quickly from disturbances
- Maintain measurement integrity over time
Why Reliability Matters More in Real Plants
1. Control Needs Trends, Not Perfection
Process control reacts to trends. A stable, repeatable signal is more valuable than a theoretically perfect one.
2. Alarms Depend on Availability
An analyzer in maintenance mode cannot protect equipment or people. Reliability ensures alarms are active when needed most.
3. Environmental Compliance Is Continuous
Regulators care about data availability as much as accuracy. Missing data periods often cause more trouble than small bias errors.
Common Causes of Poor Reliability
- Sample system design issues
- Condensation and moisture ingress
- Particulate fouling
- Frequent calibration drift
- Inadequate maintenance access
Most analyzer failures are caused by sample systems — not analyzers.
The Technician’s Role
- Clean and heated sample lines
- Maintained filters
- Realistic calibration routines
- Meaningful alarm limits
Conclusion
Accuracy impresses on paper. Reliability delivers in the field.
The best analyzer systems are those that technicians can keep running, operators can trust, and plants can depend on.