• Performance
• Static Characteristic
• Dynamic Characteristic
• Calibration
• Uncertainty in instruments
• Deterministic and stochastic error
• Methods of calibration

Performance

Static characteristics:

1. Precision
2. Accuracy

1. Response characteristic
2. Dynamic Accuracy

Calibration

Uncertainty in instruments

There are many uncertainties that affect the precision and accuracy of a measurement system. These uncertainties depend on:
• The performance limit of instruments
• The measurement environment such as temperature, humidity, altitude, etc.
• the difference between different operators in operating procedure, technique etc.

Deterministic and stochastic error

The measurement error caused by various uncertain factors can be divided into the following categories according to the nature of errors:

Deterministic error:  The errors are caused by system error such as error due to design principle, temperature shift etc.  Deterministic error of a measurement system can be eliminated by calibration.

Stochastic error:  The errors are caused by stochastic factors. For Example, white noise of instruments, heat noise of electrical components. The kind of error can be described by statistical method.

Methods of Calibration

There are many methods to calibrate lengths, mass, force, torque, angle, flatness, and roundness. Below are some example of calibration.
 
 
• Gage block lengths can be calibrated interferometrically or with a comparison-to-master-block technique.
• Ball plates, ball jars, glass grid charts, end standards, and step standards are all calibrated using a custom built CMM.

Force machines, load cells, proving rings, dynamometers, and force gages can be calibrated over the range of 1 milligram to 500,000 pounds force.