- If the hole is found: PC-DMIS will move to the down to the “check distance” depth and proceed to take three hits equally spaced around the hole to determine the general location of the hole. Following this general adjustment PC-DMIS will then measure the hole using the parameters defined by the user in the tab for the feature. This includes Sample hits etc. This is the same as the CENTER item describe above.

- If the hole is not found: PC-DMIS will back away from the surface and start a circular search pattern that is (feature radius – probe radius) out from the theoretical feature center. The search will try (2 * PI * feature radius/(feature radius – probe radius)) locations around the search circle. If the hole is still not found the search radius will be increased by (feature radius – probe radius) and will continue until the search radius is equal to the prehit distance. If the prehit is smaller than (feature radius – probe radius) only one search pattern will be completed.

- If the hole is never found: PC-DMIS will move the probe to a position of a prehit above the theoretical center of the feature and prompt the user to do a “Read Position”. (See "Read Pos / Read Position button".)

- Adjustments along the surface normal: As PC-DMIS searches and finds a surface instead of the hole it will continually update the search height based on the found surfaces. Once the hole is found, it will update the depth of measurement of the hole based on the last surface found. If the hole is found the first time, no adjustments are made.

- Adjustments with RMEAS: If you supply an RMEAS feature (or features) PC-DMIS assumes you desire to use the feature(s) as the reference for both the search height and the depth of the hole measurement. Therefore, there will be no adjustment along the surface normal other than the RMEAS adjustment.

- If the hole is found: PC-DMIS will move down to the “check distance” depth and measure one hit on each of four the sides of the slot. It will adjust for the center of the four hits and measure two hits on one of the long sides to adjust for the slot rotation. After a general location and orientation of the slot is calculated, the Slot will be measured using the parameters defined in the tab for the feature.

- If the hole is not found: PC-DMIS will back away from the surface and start a circular search pattern that is (feature radius – probe radius) out from the theoretical feature center. The search will try (2 * PI * feature radius/(feature radius – probe radius)) locations around the search circle. If the hole is still not found the search radius will be increased by (feature radius – probe radius) and will continue until the search radius is equal to the prehit distance. If the prehit is smaller than (feature radius – probe radius) only one search pattern will be completed.

- If the hole is never found: PC-DMIS will move the probe to a position of a prehit above the theoretical center of the feature and prompt the user to do a “Read Position”. (See "Read Pos / Read Position button".)

- Adjustments along the surface normal: As PC-DMIS searches and finds a surface instead of the hole it will continually update the search height based on the found surfaces. Once the hole is found, it will update the depth of measurement of the hole based on the last surface found. If the hole is found the first time, no adjustments are made.

- Adjustments with RMEAS: If you supply an RMEAS feature (or features) PC-DMIS assumes you desire to use the feature(s) as the reference for both the search height and the depth of the hole measurement. Therefore, there will be no adjustment along the surface normal other than the RMEAS adjustment.

- If the hole is found: PC-DMIS will move down to the “check distance” depth to measure the hole's depth, and then to measure the hole.

- If the hole is not found: PC-DMIS will back away from the surface and start a search pattern. The pattern is circular and is adjusted out one half the width from the theoretical feature center (which for notches, is the center of the inside edge.). The search will try eight locations around that location. If the hole is found, the probe will move to the depth to measure the hole's depth, and then to measure the hole.

- If the hole is never found: PC-DMIS will move the probe to a position of a prehit above the theoretical center of the feature and prompt the user to do a “Read Position”. (See "Read Pos / Read Position button".)

If you respond by clicking the Yes button, PC-DMIS will require you to place the probe in a cylindrical zone above the circle.

Placing the Probe in the Cylindrical Zone: You only need to place the probe in the center of the imaginary 3D cylinder of the hole. The depth and orientation of the measurement will then be automatically determined by one of the following:

- RMEAS feature: If you provide an RMEAS feature, PC-DMIS assumes you want to measure the hole with respect to that feature (or features). Therefore, the feature(s) will be used to define the surface normal and depth of measurement, while the Read Pos will be used to determine the other two axes of translation.

- Find Hole: If Find Hole is used and the surface around the hole is touched at least one time, then PC-DMIS will adjust all three axes. Two of the axes are based on the location of the probe once it has found the hole and the third axis, along the surface normal, is based on the last surface touched. Find Hole will not override an RMEAS feature.

- Sample Hits: If sample hits are used they are always the top priority on determining both the orientation and depth of measurement of the hole.

- None of the above: If none of the above options are used, PC-DMIS will probe the hole based on the provided target and depth values, adjusted by the probe placement within the cylindrical zone.

### Working with Contact Find Hole Properties

Contact Find Hole Properties Tab

This tab becomes visible when you have the Auto Feature dialog box open and a contact probe is enabled. The items become available for selection if PC-DMIS is in DCC mode.

The Contact Find Hole Properties tab contains items that allow you to change Find Hole properties for Auto Features that use contact probes.

General Find Hole Process

Once you select a routine from the Find Hole list (NOCENTER, SINGLE HIT, or CENTER) and execute your part program, PC-DMIS positions the probe a Prehit Distance above the theoretical center of the feature, then drives normal to the feature surface vector searching for the hole at touch speed. The search will continue until either the surface is touched (indicating that the hole is not there) or until the check distance is reached (indicating that the hole is present). See "Check Distance" in the "Setting Your Preferences" chapter section.

If Find Hole fails, PC-DMIS displays the Read Position dialog box. This gives you the choice to either read a new position from which to continue searching for the hole (click Yes), or to skip this feature and move on to the next feature (click No).

- If you choose Yes, you can then use your jog box to move the probe to the new location.

- If you choose No, PC-DMIS moves the probe away from the hole by the distance specified for an Avoidance Move (see "Working with Contact Auto Move Properties") and continues running the part program. This movement helps to prevent a possible probe collision.

Additionally, you can set PC-DMIS to automatically continue executing the part program when the hole can't be found. See "Auto Continue Execution if FindHole Fails" in the "Setting Your Preferences" chapter section.

Tab Items

Depending on the type of feature in the Auto Feature dialog box, this tab may change to contain one or more of the following items:

Item | Supported Auto Features | Description
Find Hole |

- Circle

- Round Slot

- Square Slot

- Notch Slot

- Polygon

- Cylinder

This list contains these list options. They determine how PC-DMIS proceeds when attempting to find a hole.

DISABLED - No Find Hole operation is performed.

NOCENTER - This item acts as the CENTER item except the probe doesn't take the three hits to find the rough estimate of the hole's center. It merely begins measuring the circle using existing parameters set in the specific auto feature dialog box.

SINGLE HIT - This setting tells the probe to take one single hit. If it hits the surface and doesn't find the hole, then it automatically switches to the "If the hole is not found" case described below. If the probe finds the hole proceeds using the NOCENTER option.

CENTER - This item first causes the probe to move down to the “check distance” depth to make sure it doesn't encounter any material. It then moves to either the feature's depth or to the Check Distance * Percent to search inside the hole for a rough estimate of the hole's center (see "Registry Items" below). The probe does this by taking three hits equally spaced around the hole. Once the probe has the hole's general location, it then proceeds to measure the hole using the parameters set in the specific auto feature dialog box. Unless NOCENTER or SINGLE HIT is selected, this is the default procedure that PC-DMIS follows if the hole is found.

Note: A Find Hole registry entry gives you greater control over the depth of the centering process. By default, the centering process’s Z component is determined by the feature’s depth. This is often used in conjunction with an Rmeas (plane) feature. However, sometimes when you don't use an Rmeas feature, and the surface of the part varies greatly in Z, the centering process will never find the hole because the part’s surface lies below the search depth. In this case, you can instead have the Find Hole centering process execute at the Check Distance * Percent, by setting the FHCenteringAtChkDistTimesPercentInsteadOfDepth registry entry to TRUE in the PC-DMIS Settings Editor. This entry is located in the USER_AutoFeatures section. See "Parameter Settings: Motion tab" to set the Check Distance and Percent values.

Find Hole Specifics for a Circle or a Cylinder

Find Hole Specifics for a Square Slot or Round Slot

Find Hole Specifics for a Notch Slot

Supported Interfaces

All the DCC interfaces support the Find Hole functionality. If you experience a problem with a specific interface, please contact technical support and we will investigate the issue.

On Hit Error |

- Edge Point

- Angle Point

- Corner Point

- Circle

- Ellipse

- Round Slot

- Square Slot

- Notch Slot

- Polygon

- Cylinder

- Cone

The On Hit Error check box allows improved error checking when PC-DMIS detects an unexpected or missed hit.

If you select this check box, PC-DMIS will:

- Automatically take a Read Position (see "Read Position" below) whenever an unexpected probe hit or missed probe hit takes place during the measurement cycle.

- Measure the entire feature with the new location obtained from the Read Position.

The Edit window command line for this option would read:

ONERROR = TOG

TOG: This toggle field switches between YES (on) and NO (off).

For additional information on what options you have when PC-DMIS detects unexpected or missed hits, see "Branching On a CMM Error" in the "Branching by Using Flow Control" chapter section.

Note: By default, when PC-DMIS performs a read position operation (such as used in Read Pos, Find Hole, or On Error) it only returns the X and Y values. However two registry entries give you further control over returning the Z axis value as well. These are: ReadPosUpdatesXYZ and ReadPosUpdatesXYZEvenIfRMeas.
V43 - ADDED FROM TASK 103011: If these registry entries are set to FALSE, the location found by the read position is snapped to the feature's normal vector and stored as the target. However, since Edge Point, Angle Point, and Corner Point features do not have a normal vector, but are instead defined by a combination of vectors, for these feature types PC-DMIS will not snap the read position location to a feature vector as it did in versions prior to v43. Instead, PC-DMIS ignores the above registry entries and assigns the target (TARG field) the XYZ of the read position.

TASK 103011:

AutoFeatures that support ReadPosition allow that read position to be stored as the target. With ReadPosUpdatesXYZ=FALSE or ReadPosUpdatesXYZEvenIfRMEAS=FALSE, the learned ReadPosition is snapped to the feature’s Normal Vector and stored as the target.

However, EdgePoint, AnglePoint, and CornerPoint support On-Error, which leads to a ReadPosition. In the case of these features, it is not practical to snap the learned ReadPosition to a feature vector. These three features have no Normal Vector, but are defined instead by a combination of vectors. Currently, PC-DMIS will snap the learned ReadPosition to the first vector of the feature; the Edge vector of EdgePoints, the Line vector of AnglePoints, and the vector for Surface #1 for Corner Points.

Enhance PC-DMIS to ignore ReadPosUpdatesXYZ and ReadPosUpdatesXYZEvenIfRMEAS during ReadPositions for these three point features. The result should be that the TARG location will be assigned the XYZ of the learned ReadPosition.

Of course, the learned ReadPosition should only be stored as a new target if the user answers YES to the question.

DOCUMENTATION TO ADD:

Supported Interfaces

All the DCC interfaces support the On Error functionality. If you experience a problem with a specific interface, please contact technical support and we will investigate the issue.

Read Position |

- Circle

- Ellipse

- Round Slot

- Square Slot

- Notch Slot

- Polygon

- Cylinder

- Cone

Selecting this check box causes PC-DMIS to pause execution above the surface feature and to display a message asking if you want to use the current data.

- If you respond by clicking the No button, PC-DMIS will require you to move the probe to the desired location before the measurement process can continue.

- If you respond by clicking the Yes button, PC-DMIS will measure the feature and will use the current probe data.

Read Position Specifics for a Circle

Note: By default, when PC-DMIS performs a read position operation (such as used with the Read Position check box, Find Hole list or the On Hit Error check box), it only returns the X and Y values. However, two registry entries give you further control over returning the Z axis value as well. These are: ReadPosUpdatesXYZ and ReadPosUpdatesXYZEvenIfRMeas.