Electrical symbols are groupings of objects that include one or more objects of type Pin. They are inserted in the document as objects of type Symbol and are defined and exported through objects Frame.
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Electrical symbols may not extend over more than one level. If you convert objects on different layers into symbols, they are combined into a single layer. |
Objects for the definition of electrical symbols
The following objects can be used to define an electrical symbol:
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All graphic objects except the following objects: OLE, Clone, Diagram, Image of a page.
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An object Hotspot to specify the origin point, or insertion point, of the symbol. In the absence of the Hotspot object, the origin of the symbol is at the endpoint of the lowest numbered pin.
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Objects of type Reference. It is used to specify the style and position of text that represents the reference of a component.
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Objects of type Value. It is used to specify the style and position of the text that indicates the type of component or the value of the component.
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Objects of type Attribute. Graphic attributes can be used to display the value of internal attributes. See To display the internal attributes of symbols in the drawing.
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Objects of type Pin. Pin-type objects allow you to represent the terminals of electrical objects. If a symbol includes at least one object of type Pin constitutes an electrical symbol otherwise it constitutes a graphic symbol.
To draw an electric symbol
The tools and the working environment are the same as those used for the realization of drawings and schematics. For example, to draw the NPN transistor symbol, do the following.
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Defining the symbol with the Frame object
For each symbol a frame type object must be drawn. These objects, represented graphically with a rectangle, allow you to delimit the objects that make up a symbol. Only objects that are entirely enclosed within the rectangle of the frame object will form the symbol. The frame object also allows you to insert some information (description, attributes, etc.) into the symbols.
After drawing the frame object, you can use the edit tool to reposition the fields: part number, name and description.
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Activate the Library layer and create the Frame for the symbol. See To add one or more frames.
Open the properties window of the Frame object and specify the name of the symbol and a brief description. See Properties of the Frame object.
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Draw the body of the symbol
Activate the Drawing layer and draw the body of the symbol.
Select a snap grid of 0.250mm. See Coordinate system bar.
Add a Hotspot object to the center of the frame to specify the origin point, or insertion point, of the symbol. See To add a Hotspot.
Place the origin of the reference system at the origin point of the symbol (center of the Hotspot object). See Set the origin via the Hotspot.
Select the "Empty" fill style.
Select the "Symbol Outline" pen style.
Draw a circle centered in (x=0.625, y=0.0) and radius of 3.125mm. See To draw a circle by specifying the center and radius.
Select the "Pin Round Terminals" pen style.
Draw the collector line from the point (x=0.0, y=0.625) to the point (x=2.5, y=2.5). See To draw a single line.
Draw the emitter line from the point (x=0.0, y=-0.625) to the point (x=2.5, y=-2.5). See To draw a single line.
Draw the base line from the point (x=0.0, y=0.0) to the point (x=-2.5, y=0.0). See To draw a single line.
Deselect the last line created.
Select the "Empty" pen style.
Select the "Black" fill style.
Draw a rectangle centered in (x=0.0, y=0.0), 0.625mm wide and 4.5mm high. See To draw a rectangle by specifying the center and dimensions.
To draw the arrow on the emitter line:
Select the emitter line and press ALT+Enter to open the Properties of the Line object dialog box.
Choose the "Use a private style" style. The dialog box for setting the Pen style opens.
Activate the Arrowhead tab.
Set "Full Arrow" for the final end of the line.
Set the width of the arrow to 600%.
Set the length of the arrow to 700%.
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Adding pins
After completing the body drawing, add the corresponding pins to the electrical terminals of the component.
Warning: When drawing an electrical symbol, it is important that the endpoints of all pins are centered exactly on the snap's electrical grid.
Select a 2.5mm snap grid. See Coordinate system bar.
Place the origin of the reference system at the origin point of the symbol (center of the Hotspot object). See Set the origin via the Hotspot.
Add base, collector, and emitter pins. See To add a pin. The pin is hooked to the mouse pointer for the non-electric end. This part of the pin must be positioned on the body of the component. Press the right mouse button to rotate the pin to the correct position. Move the pin and click to place it in the drawing.
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Add Reference
For electrical symbols, an object of type Reference must also be specified. See To add a Reference object.
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Add Value
For electrical symbols, an object of type Value must also be specified. See To add a Value object.
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Specify the origin point of the symbol
Objects of type Hotspot must be used to specify the origin point, or insertion point, of the symbol. For electrical symbols, the insertion point must correspond to the electrical terminal of a pin. In the absence of the Hotspot object, the origin of the symbol is at the endpoint of the lowest numbered pin.
Select the Hotspot object and move it to the endpoint of the base pin.
Adding information to the symbol
You can associate data and information to objects using attributes. Attributes are characterized by a name, a category and a value. There are two types of attributes:
Internal attributes. Internal attributes can be associated with any object. The value of an internal attribute cannot be displayed directly in a drawing. See Internal attributes of objects.
Graphic attributes. Graphic attributes are objects of type Attribute and can only be associated with the following object types: group, symbol, sheet, device. Graphic attributes can be used to display the value of internal attributes.
Creating multiform symbols
Multiform symbols define multiple alternative shapes. For this type of symbol you can choose the shape once the symbol has been placed in the drawing. For example, ten shapes can be defined for the seven-segment display symbol, one for each number that can be displayed on the display. See To create multiform symbols.
Creating dynamic symbols
Although it is possible to make transformations on a symbol as well as on the individual objects that compose it, the symbol always maintains its basic structure. For example, considering a symbol simply consisting of a four-sided polygon: you can resize and rotate the symbol but it will always remain a four-sided polygon. With dynamic symbols, however, you can drag a hook so that the symbol can change its structure; the four-sided symbol that described a square can take the form of a pentagon or an octagon. Unlike multiform symbols that allow you to choose from a number of prefixed shapes drawn when defining the symbol, dynamic symbols can dynamically calculate their shape by means of a procedure linked to the symbol. See To create dynamic symbols.