Unary and Binary Rule Types

There are two types of design rules - unary and binary. Unary rules apply to one object, or each object in a set of objects. As a consequence, unary design rules have one rule scope. Binary rules apply between two objects, or between any object in one set to any object in a second set. As a consequence, binary design rules have two rule scopes.An example of a unary rule is the Solder Mask Expansion rule. This rule applies individually to each pad identified by the rule scope.

An example of a binary rule is the Clearance rule, which applies between any copper object in the first set and any copper object in the second set, as identified by the separate queries of the two rule scopes.

Viewing Applicable Unary Rules

For any placed object in the current design, you can quickly access information about which unary design rules apply to that object. Position the cursor over the object (or select it), right-click and select Applicable Unary Rules from the pop-up menu. The Applicable Rules dialog will appear.

All defined design rules that could be applied to the selected object are analyzed and listed in the dialog. The specific constraints for each rule are also displayed.

Each rule that is listed in the dialog will have either a tick ( ) or a cross ( ) next to it. A tick indicates that this is the rule with the highest priority out of all applicable rules of the same type and is the rule currently applied. Lower priority rules of the same type are listed with a cross next to them, indicating that they are applicable but, as they are not the highest priority rule, they are not currently applied.Any rules that would apply to the object but are currently disabled also have a cross next to them and are shown using strike through highlighting.

Viewing Applicable Binary Rules

In a similar fashion, you can also access information about the binary design rules that apply between two placed objects in a design. Position the cursor over any object, right-click and select Applicable Binary Rules from the pop-up menu. You will be prompted to select two objects in the design. Position the cursor over each object in turn and click or press ENTER . The Applicable Rules dialog will appear, displaying all binary design rules that apply to those objects.

Note : If the two objects that you select do not have any binary rules applied to them, the Applicable Rules dialog will not open.

Working from the Rule to the Object in the Workspace

Rather than interrogating an object to see which rule applies to that object, or between two objects, you can also work from a list of rules and see what objects they apply to in the workspace. This can be achieved from the PCB Rules and Violations panel.

As you click on a specific rule in the Rules region of the panel, filtering will be applied, using the rule as the scope of the filter. Only those design objects that fall under the scope of the rule will be filtered, the visual result of which (in the main design window) is determined by the highlighting options enabled (Mask / Dim / Normal , Select, Zoom).

For more information about the PCB panel, press F1 when the cursor is over the panel.