The probe stylus slots into the end of what is in effect a reference "ball" bar. The probe carries the bar with it over a spherical path, and radial readings are taken at different positions. The range of these readings indicates the volumetric measuring performance of the CMM. Repetition of a sequence of readings checks the system for repeatability.

Volumetric measuring performance is the maximum error between any two points in any plane, over any distance within the full measuring volume.

Special calibrated stylus can be used with TP1, TP2, TP20, TP6, TP6A, MIP and PH50 with suitable adaptors.

The online MCG service

Using the MCG has never been easier with Renishaw's online MCG service. In three easy steps, we help you to measure, analyse and track the volumetric performance of your CMM:

1. Create an MCG test program to run on your CMM - a DMIS program is generated for you from a set of parameters that you specify. You can run this on your CMM to generate a set of measurement results.
2. Analyse your MCG test results - the MCG test generates a set of measurement results, again in DMIS format. You can upload these and have them analysed online. We provide guidance to help you to interpret the data.
3. Store and retrieve previous results to spot trends - you can store your MCG test results online and retrieve them at a later date, allowing you to identify changes in the performance of your CMM over time.