Altium NEXUS Documentation

PlaceBus

Created: June 7, 2017 | Updated: October 19, 2017

Parent page: Schematic Commands

The following pre-packaged resource, derived from this base command, is available:


Applied Parameters: None

Summary

This command is used to place a Bus object onto the active document. A bus is an electrical design primitive. It is a polyline object that represents a multi-wire connection.

For detailed information about this object type, see Bus.

Access

Buses are available for placement in the Schematic Editor only, by:

  • Choosing Place » Bus from the main menus.
  • Locating and using the Bus command () on the Active Bar.
  • Clicking the  button on the Wiring toolbar.
  • Right-clicking and choosing Place » Bus from the context menu.

Use

After launching the command, the cursor will change to a cross-hair and you will enter bus placement mode. Placement is made by performing the following sequence of actions:

  1. Click or press Enter to anchor the starting point for the bus.
  2. Position the cursor and click or press Enter to anchor a series of vertex points that define the shape of the bus.
  3. After placing the final vertex point, right-click or press Esc to complete placement of the bus.
  4. Continue placing further bus objects, or right-click or press Esc to exit placement mode.
  5. Use the Backspace or Delete keys to remove the last bus segment placed.
Press the Tab key during placement to access the Properties panel, from where properties for the bus can be changed on-the-fly. Pressing Tab pauses placement, allowing you to interact with the panel (or other area of the software) directly. To resume, click the pause symbol that appears over the workspace.

Placement Modes

When placing a bus there are 3 'manual' placement modes, 2 of which have Start and End sub-modes. The mode specifies how corners are created when placing buses and the angles at which buses can be placed. During placement:

  • Press Shift+Spacebar to cycle through the 90 Degree, 45 Degree and Any Angle modes.
  • While in the 90 Degree or 45 Degree mode (known as true orthogonal modes), press Spacebar to cycle between the Start and End sub-modes.
  • During placement, the current placement mode is displayed in the Status bar. You can change modes at any time during bus placement.
  • In modes other than Any Angle, the line segment attached to the cursor is a look ahead segment. The segment you are actually placing precedes this look ahead segment.

 45 degree mode

 90 degree mode

 Any angle mode

Press Shift+Spacebar to cycle through the different placement modes.

There is also an Auto Wire mode, which can be used to route quickly from the previous segment end, to the point where the cursor is clicked, using the Point to Point Router. The path of the route will be the most efficient possible, while avoiding existing placed objects on the sheet.

Guided wiring of a Bus

Schematics have a definable 'electrical grid' that makes it easy to define electrical connections between objects. As you are placing a bus, when the bus falls within a defined range of attraction of another electrical object the cursor will snap to the fixed object and a Hot Spot (red cross) will appear.

Hot Spot (red cross).

The Hot Spot guides you to where a valid connection can be made and automatically snaps the cursor to electrical connection points.

The range of attraction, or distance within which an object will electrically snap to the hotspot of another electrical object, can be defined using the Snap Distance field, in the General section of the Properties panel (when no objects are selected on the sheet). It is recommended that you set this 'object snapping' range to be slightly smaller than the current snap grid, or it becomes difficult to position electrical objects one snap grid apart. Object snapping can be toggled on or off using the Shift+E keyboard shortcut, or by enabling/disabling the Snap option (above the Snap Distance field in the Properties panel).

Tips

  1. For information on how a placed bus object can be modified graphically, directly in the workspace, see Graphical Editing.
  2. A T-junction in a bus is automatically connected by a junction (Compiler-Generated Juntion). If the Break Wires At Autojunctions option is enabled, on the Schematic - General page of the Preferences dialog, an existing bus segment will be broken into two at the point where an autojunction is inserted. For example, when making a T-Junction, the perpendicular bus segment will be broken into two segments, one each side of the junction. With this option disabled, the bus segment will remain unbroken at the junction.
  3. While attributes can be modified during placement (Tab to bring up the Properties panel), bear in mind that these will become the default settings for further placement unless the Permanent option on the Schematic - Defaults page of the Preferences dialog is enabled. When this option is enabled, changes made will affect only the object being placed and subsequent objects placed during the same placement session.
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