Electrical Symbol Creation

As technologies advance, it is important to be aware of integrated solutions. Software has adapted and evolved in order to allow users to work smarter without necessarily having to work harder. 

This series of blogs will focus on offerings from the Solid Edge Electrical wiring and Harness Design portfolio. Topics such as electrical symbol creation, building component analysis models, failure modes, system analysis, and ECAD and MCAD integration will be covered. 

Electrical symbol creation is the starting point for this blog series. Solid Edge Wiring and Harness Design has multiple quick start symbol libraries available, inclusive of a symbol creation tool available to users. These symbols are used for various wiring design applications including schematic design as well as qualitative or numeric schematic analysis.

Electrical symbol creation

Solid Edge Wiring and Harness Design includes a 2D drafting application for electrical symbol creation. These symbols can include electrical devices, back shells, grounds, splices, or any other symbol that is necessary. All symbols that are created will be stored in a user-defined library. This allows the user to group sets of symbols for ease-of-use when designing. An insertion point marker as well as a grid facility are displayed in order to aid symbol construction and define the scale. 

Electrical symbol creation

Symbols can be created through the following process:

  1. Open or create the appropriate library in the Electrical Symbols application. Right-click the library folder and select ‘New Symbol’ from the menu. 
  2. Specify the symbol name and symbol type (device, back shell, splice, ground) in the ‘New Symbol” pop-up. 
  3. Click ‘OK’ to create the new symbol.
  4. Construct the new symbol using the graphic drawing tools (lines, rectangles, arcs, blocks, pins, links) available in the Solid Edge Electrical Symbol ‘Home’ tab.

The two images above represent a 12AX7 Vacuum Tube symbol. Vacuum Tube symbols are not included in the quick start libraries and therefore will not be used to illustrate symbol creation. 

The first image shows the full layout of the tube inclusive of cathodes, anodes (plates), heaters and a heater tap. Internal links (blue lines) are used to show the plate

resistances, as well as the heater configuration. The internal links (blue lines) can be defined as resistive, fuse or diode elements. The white dots around the 12AX7 are external pins, while the red dots represent internal pins. The insertion point marker can be seen at the centre of the symbol. 

The second image shows one half of a 12AX7 Vacuum Tube, excluding the heater element, represented as a symbol. each half of a twin-triode vacuum tube is independent and can be modelled as such depending on the application. This symbol will be used to discuss component analysis models. 

Attaching component models

The component analysis model defines the electrical behaviour of the created symbol. This required that an analysis model be built, attached to the symbol and edited based on the behaviour of the model in the wiring design. By selecting the ‘Build’ button on the ‘Home’ tab of the Electrical Symbol application, users can define the node and arc details as shown in the image below. 

Once the node and arc details have been defined it is possible to detail operation modes, failure modes, component interface properties and quantisation schemes for the associated symbol. 

For the purpose of this blog, the plate resistance between the anode and cathode is modelled. The anode and cathode are represented as nodes and the plate resistance is characterised using an infinite resistance arc as can be seen in the image above. Once the component model has been built, it can be attached to the symbol by clicking the ‘Attach’ button on the ‘Home’ tab and browsing to the location of the model. 

If the component model is not behaving as expected in the Wiring Design environment, it can be edited within the Electrical Symbol application. By selecting the ‘Edit’ button on the ‘Home’ tab it is possible to add component interface properties (as seen in the second image of this blog where a DC Resistance property is added), edit or add failure modes for the component being modelled, edit the structure of the node and arc details and edit the behaviour of the operating mode as shown in the image below.  

The dependancy editor is used to adjust the behaviour of the model and consists of a text field on the left for the dependancy expressions as well as a tree of code placeholders (used to construct the behaviour) on the right. Further information regarding the dependancy editor can be found in the Solid Edge Electrical Analysis User Guide. Once the component analysis model is functional, the symbol can be used for design and analysis within the Solid Edge Wiring and Harness Design application.

Author: Dylan Naidu, Application Engineer at Ultimate Partner, October 2020.