Defining the Harness Wiring Diagram in Altium Designer

The individual wired connections within the harness are specified in the harness wiring diagram (*.WirDoc). Add this document to the harness project from the Projects panel by right-clicking on the project entry and then selecting Add New to Project » Harness Wiring Diagram from the context menu (or use the File » New » Harness Wiring Diagram command from the main menus).

Setting Up a Harness Wiring Diagram Document

Options of a harness wiring diagram document can be configured in the Properties panel when no object is selected in the document's design space. The main settings are:

• In the General region of the panel's General tab – select the measurement units that apply to the document and its graphic elements and set the grids to enable easier placement. Altium Designer offers three grid types: visible grid for navigation, snap grid for placement, and snap distance for aiding the creation of connections.

• In the Page Options region of the panel's General tab – configure document sheet size and title block or select from available harness wiring document templates.

 
The General and Parameters tabs of Properties panel when no object is selected in the harness wiring diagram document

Synchronizing Multi-board and Harness Projects

When the harness project is part of a multi-board design project, the harness wiring diagram can be synchronized from the multi-board schematic document (*.MbsDoc) data. To do so, select the Design » Import Changes From <Multi-board Project> command from the main menus.

Learn more about Adding a Harness Design Project to a Multi-board Project.

If the multi-board schematic document contains more than one harness connection definition, the Select Harness Definition dialog will open. Specify the definition that relates to the current harness project.

The Select Harness Definition dialog

The Engineering Change Order dialog will then open showing the harness connector components and harness nets that were defined in the multi-board schematic, which will form the basis for the harness wiring diagram.

The Engineering Change Order dialog

After executing the changes (Execute Changes), the data from the multi-board schematic document are imported into the harness wiring diagram. The connector components, each represented by its schematic symbol, will appear in the harness wiring diagram document, initially in arbitrary positions.

An example of a harness wiring diagram right after import.

Netlines will be shown between the pins to represent the logical connections defined in the multi-board schematic. Note that at this stage, there are no physical wires in the design.

Working with Components

As well as synchronizing from the multi-board schematic document, components can also be placed manually into the harness wiring diagram. This allows components to be placed in a standalone harness project (that is not part of a multi-board project), but also allows additional components to be placed in a harness wiring diagram that is part of a multi-board project.

Use the Components panel to place the symbols of the required components. The component placement process is similar to that in the Schematic editor – refer to the Searching for & Placing Components page to learn more. Note that there will be no net lines for manually added components, as there is no higher-level logical design to drive them.

To move a placed component (or a component being placed from the Components panel) to the desired position, click and hold the left mouse button on it and move the mouse. During dragging, use the Spacebar to rotate the components by 90 degrees and the X and Y keys to flip them horizontally and vertically, respectively.

The harness wiring diagram after moving the components

Click a component in the design space or hover the cursor over the desired component, then click Properties to present its options in the Properties panel.

The Properties panel for a component includes the following tabs:

• General – general properties of the component, such as designator and comment, location, parameters, etc.

• Pins – the list of component pins.

• Cavities – allows socket cavities to be assigned to the component (learn more).

• Associated Parts – allows additional parts, such as heatshrink, to be assigned to the component.

Assigning Socket Cavities

Socket cavities and their type can be assigned to a component. Select a harness component in the design space to add a cavity and type. Select a pin on the Properties panel's Cavities tab, then click Add. Select the desired type from the drop-down. The following cavity types are supported:

• Crimp – used to provide an electrical connection by compressing a contact barrel around a conductor. For this cavity type, you can specify Strip Length and Pull Off Length values.

• Seal – used to provide environmental protection by sealing the wire entry point.

• Plug – used to fill an open (unused) connector cavity to maintain the integrity of the environmental seal.

• Other – used to specify other/additional parts or materials, e.g., solder.

In the Select Connector dialog that opens, browse to and select the desired connector. The specific type and pertinent information will be added to the pin on the tab, as shown in the images below, for adding a seal to pin 4.

Only one cavity of a particular type can be added to a pin. Once a cavity of a particular type has been added, the entry is unavailable (grayed out) in the drop-down.

Pins with assigned crimps are denoted by the   symbol in the design space, as shown in the image below. 

The grid region of the Cavities tab supports multi-selection and copy/paste/delete operations for selected entries.

• Multiple pin entries can be selected using Click, Hold&Drag, Ctrl+Click, Shift+Click, or Ctrl+A shortcuts.

• When multiple pin entries are selected, click Add to add a connector to all selected pins or click  or press Delete to remove assigned connectors from selected entries. 

• To change a pin's connector, select the pin, then click  to open the Select Connector dialog to select the new connector.

• Select one or more pin entries and use Ctrl+X/Ctrl+C shortcuts to cut/copy selected entries, then use the Ctrl+V shortcut to paste cut/copied content at the currently selected entry.

Creating Connectivity in the Harness Wiring Diagram

Physical wires are placed in the harness wiring diagram document by selecting the Place » Harness Wire command from the main menus, the Harness Wire command in the editor's Active Bar, or by using the Shift+W shortcut.

After selecting the command, click a pin of a connector (a red cross appears at the cursor when it’s over a pin's hotspot) to place the start point of the wire. Position the cursor and click to anchor a series of vertex points that define the shape of the wire. After placing the final vertex point at another pin's hotspot, right-click to complete placement of the wire.

When placing a harness wire, press Shift+Spacebar to cycle through placement modes. The mode specifies how corners are created when placing wires and the angles at which wires can be placed.  While in the 90 Degree or 45 Degree mode (true orthogonal modes), press Spacebar to cycle between the Start and End sub-modes.

When placing a wire, the netlines track/refresh 'live,' showing you where to wire in real-time, as demonstrated in the video below. Note that netlines for completed connections disappear from the document.

Demonstration of the live trace feature.

When placed and selected, a harness wire’s vertices can be dragged to change the angle between two adjacent sections.

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Select a wire in the design space to change it in the Properties panel. From the panel, you can rename the selected wire, change its width and color, and add parameters that can be shown or hidden in the design space.

The Properties panel when a wire is selected

Working with Multiple Sheets

A full harness wiring diagram can be defined over multiple sheets (in a 'flat' design fashion, where all sheets exist on the same level), each represented by its own *.WirDoc document. The connectivity is created directly from any sheet to any other sheet using wire break objects with the same wire designator.

To place a wire break in the harness wiring diagram document, select the Place » Wire Break command from the main menus or the Wire Break command in the editor's Active Bar. Position the wire break so that its electrical hotspot (the end held by the cursor) touches the wire to which you want to connect, then click or press Enter to effect placement. A placed wire break inherits properties (designator and color) of the wire to which it is connected.

Select a wire break in the design space to change it in the Properties panel. From the panel, you can define the designator of the wire to which it is connected and its style: direction (Left or Right) and color.

Placing a Harness Wiring Component

When connected to your Workspace, you can create components with predefined structure and properties as required in the connected Workspace and then reuse those components in your harness designs, placing them directly in harness wiring diagram documents.

Refer to the Creating a Harness Wiring Component page to learn more about creating such components in your Workspace.

These components (each with a defined harness wiring model assigned) are accessed from the Components panel. When the required harness wiring diagram document is the active document in the design space, place a component by right-clicking its entry in the panel and selecting the Place <ComponentName> command from the context menu. The behavior of placing a component differs depending on whether the component includes a single wire object or a cable structure (multiple wires and/or additional objects: cables, shields, etc.).

• Single wire – when placing a component that includes a single wire object, you will enter harness wire placement mode. The wire being placed will inherit the properties defined during component creation. Refer to the Creating Connectivity in the Harness Wiring Diagram section above to learn more about harness wire placement.

• Cable structure – when selecting the placement command for a component that includes a cable structure, that cable structure will appear attached to the cursor exactly as it was defined during component creation. Click in the desired place of the harness wiring diagram document to place the component. You can then individually edit objects of the component, for example, to attach wires composing the cable to the pins of harness connectors.

Adding Cables

To define one or more wires as added to a cable, you can place a Cable object on the harness wiring diagram using the Harness Cable command from the Active Bar or the Place main menu.

Place a Harness Cable to define one or more wires as added to a cable.

When a cable object is selected, the wires covered by this cable are highlighted in the design space in neon green, as shown in the above image.

Properties of a placed cable object (its location, visual representation, and parameters) can be configured in the Properties panel when the object is selected in the design space.

The Properties panel when a cable is selected

Adding Splices and Taps

In design situations where a new wire should be connected to an already placed wire, a splice or tap object must be placed first. Use the commands from the associated menu of the Active Bar to place a required object.

• Splice – the original wire is split into two separate wires by the splice.

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  Another wire should be connected to the selected wire. A splice placed on the wire. Note that the splice splits the original wire into two in the splice location. Another wire has been connected to the splice.

  When two wires are connected in a T-type fashion, a splice is placed automatically at the location of the T-junction ().

• Tap – the original wire remains unbroken.

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  Another wire should be connected to the selected wire. A tap placed on the wire. Note that the tap does not split the original wire. Another wire has been connected to the tap.

Properties of a placed splice or tap (its location and visual representation) can be configured in the Properties panel when the object is selected in the design space.

The Properties panel when a splice/tap is selected

The Associated Parts region of the Properties panel allows parts such as heatshrink to be assigned to the selected entity, which will be reflected in the project's BOM.

Wire Shielding and Twisting

A shield (without or with a connection, such as a drain wire connection) can be attached to a group of wires by placing either a shield or shield with connection object. Use the commands from the associated menu of the Active Bar to place a required object.

In the example below, three wires are shielded by a shield without a connection.

Placed shield

In the next example, the same three wires are shielded by a shield with connection, and a wire is placed to connect the shield to a component pin.

Placed shield with connection

When a shield or shield with connection object is selected, the covered wires are highlighted in the design space in neon green, as shown in the above images. If a shield is associated with wires in multiple places on the harness wiring diagram (using the same designator), selecting a shield will highlight all associated wires in the group ().

Properties of a placed shield or shield with connection object (location and visual representation) can be configured in the Properties panel when the object is selected in the design space. The Shield Objects region of the panel lists wires covered by the selected object.

The Properties panel when a shield is selected

Wires can be denoted as twisted together by placing a twist. To do this, select the Twist command in the editor's Active Bar.

A twist can be placed across two or more wires. In the example below, the black and pink wires are twisted together, and the red and yellow wires are twisted together.

Place a twist to denote two or more wires as twisted.

When a twist is selected, the covered wires are highlighted in the design space in neon green, as shown in the above image. If a twist is associated with wires in multiple places on the harness wiring diagram (using the same designator), selecting a twist will highlight all associated wires in the group ().

The properties of a placed twist (its location and visual representation) can be configured in the Properties panel when the object is selected in the design space. The Twist Objects region of the panel lists wires covered by the selected twist.

The Properties panel when a twist is selected

Unconnected Wires

Unconnected wire ends are indicated with a solid square.

An indicated unconnected wire

A wire end should not be unconnected. If the design requires an unconnected wire end, a no connect object should be placed at the end. Use the No Connect command from the Place menu or the Active Bar to place a No Connect object.

Place a no connect object at the end of a wire that should remain unconnected.

Properties of a placed no connect object (its location and visual representation) can be configured in the Properties panel when the object is selected in the design space.

The Properties panel when a no connect object is selected

Working with Text Frames and Notes

Object designators can be added as active links in text frames and notes. The links provide cross-probe capabilities in the harness wiring diagram and harness layout drawing. To create active links, place a text frame or note object in either the harness wiring diagram or harness layout drawing. In the Text field in the Properties region of the Properties panel, enter @. A drop-down of all designators will appear. Double-click the desired designator from the list; the link is created in the Text field and in the design space. Click the link in the design space to cross-probe to that object in the associated document (i.e., the document that is not currently active). The process is demonstrated in the video below.

Annotating Harness Objects

Use the commands in the Tools » Annotation menu to annotate the following objects in the harness wiring diagram document:

• Wire

• Splice (Tap)

• No Connect

• Cable