Current Help System: PC-DMIS Vision (View Core Help)

#### Step 5: Measure Datums B and C

In this step, the front line
and left line
will be measured for Datums B and C. Based on the intersection of the two lines, an point
will also be constructed to establish the XY origin.

To measure Datums B:

1. Select the Magnification tab and adjust the magnification to about 25% of maximum (the actual magnification value will vary depending on your lens.).

2. Select the Illumination tab and set the Top Light to 0% (Off)and the Bottom Light to 35%.

3. Select the tab.

4. Select Scale-To-Fit from the Graphics Modes toolbar if necessary.

5. Select the Curve Mode button from the Graphics Modes toolbar.

6. Click the Line button from the Auto Feature toolbar. This opens the Auto Feature (line) dialog box.

7. Click a point
   for the left anchor point of the line on the front edge towards left end.

8. Click a point
   for the right anchor point of the line just to the left of the slot (to the right of the "V" as show below). The target is displayed.

Since the line stretches across a void (the "V"), this region must be excluded so no points are taken in that segment.

9. Right-click inside the rectangular target. From the popup menu, select Insert Hit Target. This divides the single rectangular target into two targets.

10. Repeat the above step to insert a third target.

11. Drag the 2 target dividers such that one is on each side of the "V".

9. Select the tab.

10. Position the camera over the part.

11. From the Illumination tab adjust the Top Light to a value that makes the surface visible but not too bright. Move Z to focus as necessary.

12. Select the Hit Targets tab . Notice three targets are shown: EA1, EA2, and EA3. The second target (EA2) that crosses the void should not be used. Double-click on Normal, in the EA2 density filed and select None.

13. Notice that the EA2 target segment display changes to indicate no data will be taken.

14. From the Auto Feature dialog box, rename the default Line Auto Feature name to DATUM B.

15. Click Create and then Close.

To measure Datum C:

1. Reselect the Line button from the Auto Feature toolbar. This opens the Auto Feature (line) dialog box.

By closing and reopening the Auto Feature dialog box, the number of targets get reset back to 1.

2. Select Scale-To-Fit from the Graphics Modes toolbar if necessary.

3. Click a two points for the on the left edge (one in the front and one in the rear).

4. Change the default name to DATUM C.

5. Click Create to add this line to the part program.

6. Click Close to exit the Auto Feature dialog box.

To construct a point from the lines intersection:

1. Select the Insert | Feature |Constructed | Point menu item or Constructed Point from the Constructed Features toolbar. The Construct Point dialog box appears.

2. Select the Intersection option.

3. From the feature list, select DATUM B and DATUM C.

4. Change the ID to FRNT LEFT CORNER then click Create, then Close.

The datum features are now created.

Next Step ...