Wrist Calibration area

Wrist Calibration area

Use the Wrist Calibration area to specify the wrist positions in a pattern of up to nine sphere measurements for indexable wrist calibration. This area becomes available for selection when you meet the following conditions:

• Set up an infinitely indexable wrist device such as the PHS or the CW43L in the Probe Utilities dialog box. See "Defining Probes".

• Set the appropriate wrist entries (DEAWrist or RENISHAWWrist) in the Option section in the PC-DMIS Settings Editor to 1. For details, see "About the Settings Editor: Introduction" in the Settings Editor documentation.

• Select the Calibrate the unit option in the Type of Operation area in the Measure Probe dialog box.

For details on using and calibrating wrist devices, see "Using a Wrist Device" appendix in the PC-DMIS Core documentation.

Defining AB Wrist Positions to Calibrate

To calibrate the wrist, you need to calibrate wrist positions in a pattern of at least three A angle positions by at least three B angle positions for a total of nine sphere measurements. The Wrist Calibration area gives you the ability to specify the angles for calibrating both the A and the B axes. Use the Start, End, and Increment boxes to specify the start and end angles for mapping the wrist, and the increment for mapping in both the A and B axes.

Suppose you use these values:

A Angle:
Start = -90
End = 90
Increment = 90

B Angle:
Start = -180
End = 180
Increment = 180

PC-DMIS calibrates the positions of A-90B-180, A-90B0, A-90B180, A0B-180, A0B0, A0B180, A90B-180, A90B0, and A90B180.

Choose the actual start and end angles according to the type of wrist device that you use, the mechanical availability, and the manufacturer or vendor recommendations. In some cases, PC-DMIS automatically determines the start and end angles based on the controller's specifications (although in these cases, PC-DMIS only maps 359.9 degrees of the B axis roll).

While a minimum of nine positions is required to calibrate a wrist device, you may choose to use more than this minimum. PC-DMIS gives you a slightly more accurate calibration if you use more than the minimum number of positions.

When you calibrate a wrist, you can also create a wrist error map to correct for angular errors in the wrist between calibrated positions. For information, see "Calculate Error Map" in the "Using a Wrist Device" appendix of the PC-DMIS Core documentation.

If you're using an SP600 probe, be sure to read the cautionary section in the "Wrist Calibration" topic in the "Using a Wrist Device" appendix in the PC-DMIS Core documentation.

Using Wrist Error Maps

Use the following controls to create, replace, view, and delete wrist error maps.

• Create New Map - This option creates a new wrist error map when you click Measure.

• Replace Closest Map - This option replaces the closest existing wrist error map with a newly created wrist error map when you click Measure.

• View / Delete Maps - This button displays the View / Delete Wrist Maps dialog box. For each mapped wrist, this dialog box lists any wrist error maps found on your system. It also shows the probe's extension length, and it lists the number of AB angles and the angle increment value. To remove a wrist error map from your system, select a wrist error map, and click Delete.