Altium NEXUS Documentation

Working with the Fabrication and Assembly Testpoint Style Design Rule on a PCB in Altium NEXUS

Modified by Jason Howie on Sep 26, 2019
All Contents

Rule category: Testpoint

Rule classification: Unary

Summary

The Fabrication Testpoint Style and Assembly Testpoint Style design rules specify the allowable physical parameters of pads and vias that are to be considered for use as testpoints for bare-board fabrication testing, or in-circuit assembly testing respectively. The constraints between these two rules are identical. 

Default Fabrication and Assembly Testpoint Style rules exist. You should check whether these rules meet your board requirements and make changes as necessary. If multiple rules of the same type are required, simply use the priority aspect of design rules to ensure that rules with more specific scoping are applied first (for example when running a DRC).

For the Testpoint Manager to successfully assign testpoints, there must always be at least one corresponding Style rule with a scope of All.
All design rules are created and managed within the PCB Rules and Constraints Editor dialog. For a high-level view of working with the design rules system, see Constraining the Design - Design Rules. For detailed information regarding how to target the objects that you want a design rule to apply to, see Scoping Design Rules.

Constraints

Default constraints for the Fabrication and Assembly Testpoint Style rule.

Sizes

The following options allow you to specify pad/via diameter and hole size criteria when testing for valid testpoints:

  • Min Size - specifies the minimum permissible diameter for a pad/via to be considered as a testpoint.
  • Max Size - specifies the maximum permissible diameter for a pad/via to be considered as a testpoint.
  • Preferred Size - specifies the diameter to be used for testpoint pads/vias placed by the Autorouter.
  • Min Hole Size - specifies the minimum permissible hole size for a pad/via to be considered as a testpoint.
  • Max Hole Size - specifies the maximum permissible hole size for a pad/via to be considered as a testpoint.
  • Preferred Hole Size - specifies the hole size to be used for testpoint pads/vias placed by the Autorouter.

Clearances

The following options allow you to define clearance constraints specific to board testing:

  • Min Inter-Testpoint Spacing - specifies the minimum permissable center-to-center distance to be observed between two adjacent testpoints, when considering a pad/via for use as a testpoint. This is typically determined by the probe head spacing for the flying probe, or bed-of-nails test fixtures, being used in the testing.
  • Component Body Clearance - specifies the minimum permissable distance to be observed between a testpoint and the body of a component, when considering a pad/via for use as a testpoint. If a component has a component body, then the clearance is applied to the component body. If a component body is absent, then the clearance is applied to the component's non-pad/via primitive objects on the Mechanical + TopOverlay/BottomOverlay layers.
  • Board Edge Clearance - specifies the minimum permissable distance to be observed between a testpoint and the edge of the board, when considering a pad/via for use as a testpoint.
  • Distance to Pad Hole Centers - specifies the minimum permissable distance from the center of a testpoint, to the center of an adjacent pad (the center of the pad's hole).
  • Distance to Via Hole Centers - specifies the minimum permissable distance from the center of a testpoint, to the center of an adjacent via (the center of the via's hole).
The software checks the distance in accordance with the layer settings of the objects under test. For example, if a thru-hole pad is only configured to be a testpoint on the bottom layer, then the minimum clearance is not checked against other pads/vias on the top layer.

Grid

Use of a grid is most appropriate when targeting a non-custom bed-of-nails fixture. To include use of a grid, enable the Use Grid option. To disable use of a grid, enable the No Grid option.

If you do want to use a grid, the following options allow you to define it in a more comprehensive manner:

  • Origin - the X and Y coordinates, specified relative to the current board origin. This allows you to align the grid with the origin of a bed-of-nails fixture.
  • Grid Size - specifies the size of the grid to be used when attempting to find valid testpoint sites (pads and/or vias). If the entry is changed to zero, the No Grid option will automatically be selected upon applying the change.
  • Tolerance - specifies the maximum permissable tolerance to use when considering how far from a specified grid a pad or via can be located and still be considered a valid testpoint location.

Allowed Side

Use these options to specify on which side of the board prospective testpoint pad/via locations can reside - either TopBottom, or both.

Allow Testpoint Under Component

Use this option to enable the use of pads/vias located underneath components (on the same side of the board as the components) for testpoint purposes. This option would typically be enabled in a Fabrication Testpoint Style rule, but not for an Assembly Testpoint Style rule - as the pad/via will typically not be accessible once the board is populated with components.

Rule Scope Helper

Use this region of the constraints to determine which objects the rule is to apply to. Simply enable the checkbox for the objects to be included - SMD PadsViasThru-hole Pads - and click on the Set Scope button. The logical query for the rule scope will be created and entered into the Full Query region for the rule.

How Duplicate Rule Contentions are Resolved

All rules are resolved by the priority setting. The system goes through the rules from highest to lowest priority and picks the first one whose scope expression matches the object(s) being checked.

Rule Application

This rule is obeyed by the Testpoint Manager, the Autorouter, the Online and Batch DRC, and during output generation. The Online DRC and Batch DRC test all attributes of the rule except the Preferred Size and Preferred Hole Size - these settings are used by the Autorouter to define the size of testpoint pads/vias that the Autorouter places.

Tips

  1. If you want to use a surface mount pad as a testpoint, the minimum hole size should be set to zero.
  2. When specifying use of a grid, if a pad/via assigned as a testpoint is not on the grid specified by the Grid Size option, it will cause a violation when performing a Design Rule Check (DRC). For example, if you set the Grid Size to 25mil, then the testpoints must be on a 25mil grid. If the testpoints do not lie on any particular grid, you can either enter a value for Grid Size that will accommodate all testpoints (the minimum setting is 0.001 mil), or you can simply specify the No Grid option.

 

Found an issue with this document? Highlight the area, then use Ctrl+Enter to report it.

联系我们

联系原厂或当地办公室

We're sorry to hear the article wasn't helpful to you.
Could you take a moment to tell us why?
200 characters remaining
You are reporting an issue with the following selected text
and/or image within the active document:
Altium Designer 免费试用
Altium Designer Free Trial
我们开始吧!首先,您或者您的公司已经在使用Altium Designer了吗?

如果您有任何需求,请点击这里联系获取当地办公室销售代表联系方式。.
Copyright © 2019 Altium Limited

既然您在使用Altium Designer,为何仍需要试用?

如果您有任何需求,请点击这里联系获取当地办公室销售代表联系方式。.
Copyright © 2019 Altium Limited

好的,实际上您无需下载一个试用版本。

点击下方按钮下载最新版本的Altium Designer安装包

下载Altium Designer 安装包

如果您有任何需求,请点击这里联系获取当地办公室销售代表联系方式。.
Copyright © 2019 Altium Limited

填写下方表格,获取Altium Designer最新报价。

点击[获取免费试用],并同意我们的隐私政策。您会接收到来自Altium的资讯,并允许其改变您的通知首选项。

如果您是Altium维保期内客户,您不需要下载试用版本。

如果您不是Altium维保客户,请填写下方表格免费试用。

点击[获取免费试用],并同意我们的隐私政策。您会接收到来自Altium的资讯,并允许其改变您的通知首选项。

您为何想要试用Altium Designer?

如果您有任何需求,请点击这里联系获取当地办公室销售代表联系方式。.
Copyright © 2019 Altium Limited

那您来对地方了!请填写下方表格申请试用吧。

点击[获取免费试用],并同意我们的隐私政策。您会接收到来自Altium的资讯,并允许其改变您的通知首选项。

Great News!

Valid students can get their very own 6-month Altium Designer Student License for FREE! Just fill out the form below to request your Student License today.

点击[获取免费试用],并同意我们的隐私政策。您会接收到来自Altium的资讯,并允许其改变您的通知首选项。

好的,您可以下载免费的Altium Designer Viewer查看文档,有效期6个月。

请填写下方表格申请。

点击[获取免费试用],并同意我们的隐私政策。您会接收到来自Altium的资讯,并允许其改变您的通知首选项。

好棒!创作是一件超酷的事情,我们可以为您提供完美的设计软件。

Upverter是一个社区导向的交流平台,专为您这样的创客量身定做。

点击这里看看吧!

如果您有任何需求,请点击这里联系获取当地办公室销售代表联系方式。.
Copyright © 2019 Altium Limited

好的,您可以下载免费的Altium Designer Viewer查看文档,有效期6个月。

请填写下方表格申请。

点击[获取免费试用],并同意我们的隐私政策。您会接收到来自Altium的资讯,并允许其改变您的通知首选项。