Pilot study on calibration of angle encoders

Project Description

Angle encoders are accurate instruments increasingly used in industry, research activities and metrology, but the calibration of these instruments is a critical issue.

Hence, a pilot study on the calibration of angle encoders is necessary. The circulating standard will be an incremental angle encoder manufactured by Heidenhain, model RON 786C.

Many NMIs inside and outside Europe showed interest in this exercise.

The technical protocol can be downloaded here>>

Progress Report 2026-08-31

This project is a pilot study on the calibration of angle encoders.

When these devices are integrated into rotary tables, the entire measuring machine is typically calibrated against a reference angle standard using standardized procedures. Conversely, calibrating an individual angle encoder is far more challenging, as the mechanical coupling between the encoder and the reference standard is extremely delicate and can significantly impact the calibration accuracy.

Currently, only a few NMIs worldwide have a Calibration and Measurement Capability (CMC) for angle encoders.
Given the growing importance of these instruments and the need for measurement traceability, this comparison started in August 2024, involving six NMIs (four from EURAMET and two from APMP). However, the project has encountered delays due to customs clearance issues and longer-than-expected measurement periods.

To date, four NMIs have completed their measurements according to the technical protocol, and the reference standard is currently back at the Pilot Laboratory for an intermediate check.

Progress Report 2023-10-02

Many NMIs inside and outside Europe showed interest in a pilot study on the calibration of angle encoders.

The circulating standard chosen for this excercise is an incremental angle encoder manufactured by Heidenhain, model RON 786C. It has been extensively characterised by INRIM.
The technical protocol is under preparation.