Inventor In-Depth: Wire Harness Design

14 Sep, 2005 By: Kevin Schneider Cadalyst

Insert and edit wire, cable and harness features on any part using Autodesk Inventor Professional

If you've worked on products that have complex wiring, you know the feeling that comes the moment that product model and wiring design -- created by separate teams -- come together. Or don't.

Fortunately, using Autodesk Inventor Professional it's easy to create wires, cables and harnesses that integrate smoothly with product designs. You can create a wire just by specifying two electrical points to be connected, and the software automatically adds a wire. Quickly import hundreds of wires using a configurable from/to list. Inventor also can maintain electrical design intent when importing wire lists into your 3D mechanical assembly as well as detect missing connectors, pins and wire definitions in the process.

As your harness design progresses, the software maintains proper electrical connections. You create all the appropriate geometry in Autodesk Inventor with one simple command. What's more, these intelligent wires move with their connectors, establishing and maintaining electrical intent in a way that's similar to the way you work with mechanical design intent. Think of this capability as functional design -- when you manipulate them, these representations of objects actually behave like their real-life counterparts.

Getting Started
Electrical parts provide the starting and ending points for wires in a wire harness assembly. You can turn any Autodesk Inventor part into an electrical part by adding pins to it. Pins are work points placed by the Cable & Harness module, which has specialized harness properties. Each pin has a unique name to distinguish it from the other pins on the part. Adding pins to a part also confers Cable & Harness properties on the part.

  1. To add pins to a part, open or edit an existing part.
  2. On the panel bar, click the Part Features pull-down menu and choose Harness Part Features.
  3. On the Harness Part Feature panel bar, click the Place Pin tool.
  4. You can now select any point on a part face, center point or circular edge to create a pin (figure 1).

Figure 1. Select any face or center point on a part to place a pin.

  1. Enter a pin name and select the green check box.
  2. Add additional pin points if needed.

Working with Wires
You can create individual wires by selecting a start point, end point, category (for the type of wire you're creating) and a wire name.

  1. To create an individual wire, create a new harness or edit an existing harness, launch the Cable & Harness module (figure 2).

Figure 2. The Cable & Harness panel includes tools for creating and editing wires, cables and segments.

  1. Select Create Wire.
  2. Select two pins for the wire start and end points.
  3. Specify a Wire ID name.
  4. Select the wire category from the Category pull-down menu.
  5. Select a wire name from the Name pull-down menu (figure 3).
  6. Select OK when finished.

Figure 3. Select two pins, define the wire category and specify the name.

Importing Wires
It's easy to import hundreds of wires quickly into your product model using a configurable from/to list. In doing so, Autodesk Inventor maintains electrical design intent so you can see instantly any missing connectors, pins or wire definitions.

You can add multiple wires automatically to the assembly using the Import Wire List tool. A CSV (comma separated value) file is used to specify the point-to-point connectivity of each wire. You can generate these files from an AutoCAD Electrical file, a spreadsheet or a database of the wire connections in the harness.

Before importing wires, you will need to add reference designators (RefDes) to each part. The RefDes is the unique identifier for each connector instance in a cable and harness design. The RefDes and Pin Name together provide the information needed to terminate a wire.

  1. To add a RefDes to a part, create a new harness or edit an existing harness by launching the Cable & Harness environment.
  2. Right-click on the part to which you want to add the RefDes.
  3. Select Harness Properties from the Context menu (figure 4).

Figure 4. Edit a part's Harness Properties from within the Cable & Harness module browser.

  1. In the RefDes field, enter a property and select OK (figure 5).

Figure 5. Add a RefDes to a part.

  1. Specify a RefDes to all parts to which the wire will be attached.
  2. Generate a wire list from AutoCAD Electrical or create a wire list in a spreadsheet (figure 6).

Figure 6. Create a wire list.

  1. Create a configuration file in spreadsheet form or from the Report tool in the Cable & Harness panel bar to map with the wire list similar to this one (figure 7).

Figure 7. Create a configuration file to map to the wire list.

  1. From the Cable & Harness panel bar, choose the Import Wire List tool.
  2. Select the CFG and CSV files and click OK (figure 8).

Figure 8. Select the CFG file and CSV wire list to import.

  1. Once the wires are imported you can select View Log to see a log file or close the dialog box to see the imported wires (figure 9).

Figure 9. Choose View Log to see the harness with imported wires.

Working with Segments
Segments define the virtual paths that wires take through the assembly. You can set segment diameters to update automatically as wires are added so segments reflect the size of the wires bundled in them. Add segments by clicking on the geometry in the assembly. Each click defines a work point that provides the 3D spline path for the segment. You can associate these work points with the geometry in the assembly, or they can be grounded by coordinates.

  1. To add a segment to harness, choose a harness to edit.
  2. On the Cable & Harness panel bar, click the Create Segment tool.
  3. Now select any points on faces, work points and circular edges in the assembly to create a segment (figure 10).

Figure 10. Create a segment by selecting various points in the assembly.

Routing Wires
After you create a segment, you can route each wire through the harness manually, or you can automatically route all the wires at the same time.

  1. To route all wires through the segment, click the Automatic Route tool.
  2. Check All Unrouted Wires, and select OK.
  3. All the wires are routed through the segment (figure 11).

Figure 11. Choose the Automatic Route tool to map wires through segment.

Defining harness and cable paths is more intuitive when you can point and click to create 3D virtual conduits in your model and easily add or move points to refine the shape of the harness. With Autodesk Inventor Professional, you can create associative relationships to ensure that your harness automatically updates as design components change.

About the Author: Kevin Schneider