#### Calculate Error Map

Normally, wrist devices are calibrated at relatively small increments (e.g. 20 degrees). When you calibrate an infinitely indexable wrist, with the Calibrate the Unit check box selected, PC-DMIS automatically creates a wrist error compensation file named abcomp.dat that it uses to correct for angular errors in the wrist. Creating an error map will increase the accuracy of the wrist when used to measure at positions not previously calibrated by allowing PC-DMIS to interpolate the probing offsets.

After calculating the error map, the results are stored on your computer’s hard drive so that any time you use the wrist, it will take advantage of the improved angular accuracy. You should only calculate the error map periodically (once a week or less), or as necessary. When calculating the error map, PC-DMIS also performs a valid wrist and tip calibration for the currently loaded probe file.

Note: You should do a wrist calibration each time the mounting of the wrist changes. Also, you should refer to your hardware and vendor information for all appropriate times to map a wrist since this can change based on device construction and manufacturer recommendations.

Once the infinitely indexable wrist device is calibrated and a wrist error map file exists, you should then tell PC-DMIS to use the error map file. To do this, select the Use Wrist Map If Available check box from the Probe Utilities dialog box (see the "Use Wrist Map If Available check box" topic in the "Defining Hardware" section). You can then create and use any position of new probe files with a minimum of calibrations.

To do this, simply create a new probe file and perform a normal tip calibration using at least one probe position on the qualification tool that maintains a link to probe file used during the Calibrate the Unit process. However, it is important that you use more then one probe position for this calibration since a better “fitting” of the probe offset data to the wrist error matrix will occur. This is especially true if several wrist positions will be utilized in the new probe file.

Note: Failure to maintain a link to the probe file used during wrist mapping will result in measurement errors.