DFM Analysis
reports results that violate constraint values. Constraints specify
the threshold at which a measurement becomes a critical violation.
You can use a system default set of constraints, or customized constraints
stored with the product or saved as an external file.
For a list of constraints and the categories
they affect, see “Analysis Constraints”.
Procedure
- Open the DFMA wizard as described
in “Setting DFM Analysis Preferences for PADS Layout”.
- In the DFMA wizard, set Preview
analysis constraints = Yes, and click the Open Constraints Editor bar.
The Constraints
Editor opens displaying the constraints whose values can be modified:
The Constraints Editor does not display categories
reporting go/no-go type violations. For example, Missing Holes,
NPTH Annular ring, Missing VIA Clearance, SMD pads without Solderpaste.
- Use the
File menu options as needed:
File Option
|
Explanation
|
|---|
Load
|
Opens the Select ERF
constraint file path dialog box. Navigate to the location of the
constraint file, and select it.
|
Save
|
Saves the modified constraint
file in the current location. The default file of the system is
not affected.
|
Save as
|
Saves the modified constraint
file at a location of the user’s choice.
|
Close
|
Closes the Constraint
Editor.
|
- Use the
Tools menu options as needed:
Tools Option
|
Explanation
|
|---|
Restore Design Defaults
|
Restores system default
values for all constraints.
|
Switch Units
|
Switches the display
units of constraints between imperial and metric
|
Expand All
|
Expands the constraints
tree to display all analysis types and their constraint value.
|
Collapse All
|
Collapses the constraints
tree to display only the analysis types.
|
- To modify a constraint value,
double-click the numerical value and enter a different value. Placing
the cursor over the selected value displays a tooltip stating the
valid range for the constraint.
- If you want to save the values
for future DFMA runs, select File > Save to
save the modified constraints.
You do not have to save modifications
to affect the current DFMA run. The constraint file found with the
project is always used for running the analysis.
Saving customized constraints
does not overwrite system values. If saved, they are always saved
at the current location with the project. If not saved, they are
saved with the project when you close the application or move to
another window.
Alternatively, use the Save
as option to save the modified file at a location of your choice.
- To use a constraint file other
than the default system file, select File > Load and
access the stored file. It replaces the file in the project.
- To restore the default system
file, select Tools > Restore Design Defaults.
