Data Sheet

LABCENTER ELECTRONICS LTD.
114
Design Rules
The first tab of this dialogue form allows us to configure constraints and minimum clearances for
the layout. We have a DEFAULT rule loaded which must apply to all layers and all net classes,
providing a set of clearances between objects equivalent to manufacturing guidelines.
The Design Rule Manager
This rule and these clearances are created automatically for each layout in order to
provide a minimum set of constraints for a board. You can change the values of the
default clearances applied to new layouts via the Design Rule Manager on the
Technology menu.
The first thing we need to decide is whether a single rule is suitable for all layers and all traces
on the layout. It is possible to create as many new rules as required and we can limit their effect
to a given layer on the PCB, a specific area of the PCB and/or a given set of connections (net
class). A great deal of information on this is available in the reference manual but for our
purposes we can manage fine with configuration of the existing rule.
Given that this equipment is intended to work out-doors we’ll need to increase the clearances
between pads and traces to improve the insulation against condensing moisture. A 20%
increase should be sufficient so we need to change the Pad-Pad, Pad-Trace and Trace-Trace
clearances from 10th to 12th.