User`s guide

5
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16 Creatin
g
Symbols for Models
Definin
g
Important S
y
mbol
Elements
Ori
g
in
The origin, denoted by a small box with a dashed outline, is the
center point that the schematic editor uses when rotating a part
instance. By convention, the origin of each symbol in the
symbol library is placed at the point of connection to the upper
far left pin on the device.
To define the s
y
mbol ori
g
in
1
From the Graphics menu in the symbol editor, select Origin.
2
Double-click the connecting point of the pin that you want
to use as the origin (usually the upper far-left pin).
Boundin
g
box
The bounding box, denoted by a large rectangle with a dashed
outline, defines the selection area for a part instance on the
schematic. By convention, the bounding box encompasses the
symbol graphics and pins.
To make proper connections, the bounding box must contain all
visible pins. If you try to save a symbol that has pins outside the
bounding box, the symbol editor issues a warning message.
Note
To make selection of closely-spaced part
instances on a schematic as easy as possible,
avoid definin
g
symbol boundin
g
boxes that are
lar
g
er than necessary.
To define the s
y
mbol boundin
g
box
1
From the Graphics menu in the symbol editor, select Bbox.
2
Click to establish one corner, and then move the mouse to
adjust the size of the bounding box.
3
Click again to quit.
The point of connection of a wire
or pin is known as the
hot-spot .
You can position the followin
g
symbol properties outside of the
boundin
g
box:
• Hidden pins, like those found
on di
g
ital parts.
• Attributes which are visible on
the schematic.