## Calibrate the Unit for Infinite Wrist Devices

When you have an indexable wrist on the CMM, PC-DMIS will allow you to access the Calibrate the Unit and Home the Unit options in the Type of Operation area of the Measure Probe dialog box.

Measure Probe dialog box

Type of Operation area showing the Calibrate the Unit option enabled

Note: This wrist calibration is only done with a single stylus, not star probes. After PC-DMIS completes this calibration, any angular position of the wrist may be utilized in new probe files by calibrating a minimum of one probe angle. For additional information, see "Calibrate the Unit" under the "Type of Operation area" topic. See the "Calibrating Probe Tips" topic in the PC-DMIS CMM documentation for general information about calibrating probes.

The Calibrate the Unit option allows you to calibrate the wrist. It only works with single-arm configurations. This procedure allows you to measure several angles on a sphere to determine the internal distances within the wrist itself. Once this information is calculated, PC-DMIS will use it to accurately predict the tip position at any A, B angle pair. This allows you to use any A, B angle in your part program without calibrating each individual position.

Note: Be sure you type your desired measurement values in the Measure Probe dialog box for the sphere measurement, and select the qualification tool before measuring with the Calibrate the Unit option selected. You can set the number of hits, the probe prehit and retract distances, and various speeds used in the measurement process from the Measure dialog box. See "Measure" in the “Defining Hardware” chapter.

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Wrist Calibration