DAY 8 — Calibration Points

What are calibration points?

Specific values at which an instrument is tested during calibration

Why are calibration points used?

They help evaluate the instrument's performance across the measurement range

What determines the selected calibration points?

The applicable standard or method manufacturer specification laboratory procedure or SOP customer or regulatory requirements and intended use

Are 0% 25% 50% 75% and 100% universal calibration requirements?

No

What are common example calibration points?

0% 25% 50% 75% and 100%

What does 0% represent in the example calibration points?

The low end of the measurement range

What does 100% represent in the example calibration points?

The high end of the measurement range

Why should calibration points cover the range?

To provide appropriate coverage of the instrument's range and intended use

What is meant by increasing points?

Measuring the selected points while the input is increasing

What is meant by decreasing points?

Measuring the selected points while the input is decreasing

Why measure the same points while increasing and decreasing?

To help detect hysteresis

What is hysteresis?

A difference in indication depending on the direction of measurement

What does a gap between increasing and decreasing readings indicate?

It indicates hysteresis

What is range coverage?

Coverage of the measurement range by the selected calibration points

Should calibration points cover only the middle of the measurement range?

No

What should multiple readings at each calibration point help evaluate?

Repeatability and random variation in the results

Why are repeat readings taken?

To evaluate repeatability and account for random variation

What is an example of repeat readings?

Taking three readings at each calibration point

How does taking more readings affect the reliability of the results?

More readings can provide more reliable results

What is hysteresis evaluated by?

Comparing readings at the same point during increasing and decreasing runs

What can a hysteresis difference indicate?

It can indicate hysteresis in the instrument

What references are listed for calibration points?

VIM3 JCGM 200:2012 and ISO/IEC 17025:2017

What other references may determine calibration points?

Applicable standards or methods manufacturer specifications and laboratory procedures or SOPs

What should a calibrator ask about selected points?

Whether the points provide appropriate coverage of the instrument's range and intended use

Does more calibration points automatically mean better calibration?

No

What should calibration points be appropriate to?

The procedure specification instrument conditions and intended use

What is the key takeaway about calibration points?

They provide meaningful data about instrument performance across its range and help detect issues such as non-linearity or hysteresis

What should be considered beyond simply measuring the middle of the range?

Appropriate coverage of the full range and intended use

What is the calibration challenge about measuring only easy points?

It asks whether measuring only the easy points represents good calibration or merely a comfortable choice

What should be investigated if increasing and decreasing readings do not match?

The possibility of hysteresis or another condition affecting the measurement