- ModEdit: editing modules PCBNEW
-
11 - ModEdit:
editing modules
11.1 - Overview.
- ModEdit is used for
editing and creating modules; this includes:
-
- Adding and removing pads.
-
Changing pad properties (shape,
layer), for individual pads or for all pads in a module.
- Adding and editing graphic
elements (contours, text).
-
Editing fields (value,
reference,...)
-
Editing the associated documentation
(description, keywords).
11.2 - Module
elements.
- A module is the physical
representation of the part to be inserted, but it must also link to
the schematic. Each module comprises three different elements:
-
The pads.
-
Graphical contours and text.
-
Fields.
- In addition, a number of other
parameters must be correctly defined if the autoplacement function
is to used. The same holds for the generation of auto-insertion
files.
11.2.1 - Pads.
- Two pad properties are
important:
-
Geometry (shape, layers, drill
holes).
-
The pad 'number',
which is constituted by up to four alphanumeric characters.
Thus, the following are all valid pad numbers: 1, 45 and 9999, but
also AA56 and ANOD. The pad number must be identical to that of the
corresponding pin number in the schematic, because it is by matching
pin and pad numbers that Pcbnew links pins and pads for the module.
11.2.2 - Contours.
- Graphical contours are used to
draw the physical shape of the module. Several different types of
contour are available: lines, circles, arcs, and text. Contours have
no electrical significance – they are simply graphical aids.
11.2.3 - Fields.
- These are text elements
associated with a module. Two are obligatory and always present: the
reference and the value fields. These are
automatically read and updated by Pcbnew when a netlist is read
during the loading of modules into a board. The reference is
replaced by the appropriate schematic reference (U1, IC3,...). The
value is replaced by the value of the corresponding part in the
schematic (47K, 74LS02,...). Other fields can be added; these will
behave like graphical text.
11.3 - Starting
ModEdit and selecting a module to edit.
- ModEdit can be started in two
ways:
-
Directly via the
icon of the main toolbar of Pcbnew. This allows creation or
modification of a module in the library. -
Double-clicking a module will launch
the 'Module Properties' menu, which offers a 'Goto Module Editor'
button. If this option is used, the module from the board will be
loaded into the editor, for modification (or saving).
11.4 - Module
Editor Toolbars:
Calling ModEdit will launch a
window like this:

11.4.1 - Righthand
Toolbar - editing

|
- This toolbar contains tools
for:
-
- Placing pads.
-
- Adding graphic elements
(contours, text).
-
- Positioning the anchor.
-
- Deleting elements.
|
The specific functions
are the following:

|
Add a pad. |

|
Draw line segments
and polygons. |

|
Draw circles. |

|
Draw circular arcs. |

|
Add graphical text
(fields are not managed by this tool). |

|
Position the module
anchor. |

|
Delete elements. |
11.4.2 - Lefthand
Toolbar – display options

|
These tools manage
the display options in ModEdit |
These options are active when the
button is pressed:

|
Display the grid. |

|
Display polar coordinates. |

|
Use units of mm (update: now
mm/inches are toggled via two buttons). |

|
Crosshair cursor. |

|
Display pad in outline mode. |

|
Display text in outline mode. |

|
Display contours in outline
mode. |
11.5 - Context
Menus.
The right mouse button calls up
menus that depend upon the element beneath the cursor:

|
The context menu for editing
module parameters. |

|
The context menu for editing
pads. |

|
The context menu for editing
graphic elements. |
11.6 - The
Module Properties dialog.
- This dialog can be launched when
the cursor is over a module by clicking on the right mouse button
and then selecting 'Edit Module'.

-
The dialog can be used to define the
main module parameters.
11.7 - Creating
a new module.
This
icon is used to create a new module.-
The name of the new module will be
requisted (this will be the name by which the module will be
identified in the library).
-
This text also serves as the module
reference, which is ultimately replaced by the real reference (U1,
IC3...).
-
The new module will require:
-
Contours (and possbily graphic
text).
-
Pads.
-
A value (hidden text that is
replaced by the true value when used).
- Alternative method:
-
When a new module is similar to an
existing module in a library or a circuit board, an alternative and
quicker method of creating the new module is as follows:
-
Load the similar module (
,
,
or
) -
Modify the reference field in
order to generate a new identifier (name).
-
Edit and save the new module.
11.8 - Adding
and editing pads.
- Once a module has been created,
pads can be added, deleted or modified.
-
Modification of pads can be local,
affecting only the pad under the cursor, or global, affecting all
pads of the module.
11.8.1 - Adding
a pad.
- Select the
tool in the right-hand toolbar.-
Pads can be added by clicking in the
desired position with the left mouse button.
-
Their properties are predefined in
the Pad properties menu.
-
Don't forget to enter the pad
number.
11.8.2 - Setting
pad properties.
- This can be done in three ways.
-
Selecting the
tool from the horizontal toolbar. -
Clicking on an existing pad and
selecting 'Edit Pad'. The pad's settings can then be edited.
-
Clicking on an existing pad and
selecting 'Export Pad Settings'. In this case, the
geometrical properties of the selected pad will become the default
pad properties.
- In the first two cases, the
following dialog window will be displayed:

-
Care should be taken to define
correctly the layers to which the pad will belong.
-
In particular, although the copper
layers are easy to define, the management of non-copper layers
(solder mask, solder pads...) is equally important for circuit
manufacture and documentation.
-
The Pad Type selector
triggers an automatic selection of layers that is generally
sufficient.
-
Note 1:
-
For smd modules of the VQFP/PQFP
type, which have rectangular pads on all four sides, i.e., both
horizontal and vertical, it is recommended to use just one shape
(for example, a horizontal rectangle) and to place it with different
orientations (0 for horizontal and 90 degrees for vertical). Global
resizing of pads can then be done in a single operation.
-
Note 2:
-
Rotations of -90 or -180 are only
required for trapezoidal pads used in microwave modules.
11.9 - Information
about automatic placement for a module.
- If the user wishes to exploit
the the full capabilities of the autoplacement functions, it is
necessary to define the allowed orientations of the module (Module
Properties dialog).

-
Usually, rotation of 180 degrees
(Translators note: French said 190 degrees...) is permitted
for resistors, non-polarised capacitors and other symmetrical
elements.
- Some modules (small transistors,
for example) are often permitted to rotate by +/- 90 or 180 degrees.
-
By default, a new module will have
its rotation permissions set to zero.
-
This can be adjusted according to
the following rule:
-
A vallue of 0 makes rotation
impossible, 10 allows it completely, and any intermediate value
represents a penalty for rotation.
-
For example, a resistor might have a
permission of 10 to rotate 180 degrees (unrestrained) and a
permission of 5 for a +/- 90 degree rotation (allowed, but
discouraged).
11.10 - Attributes.
- The attributes section is the
following:
-
Normal is the standard
attribute.
-
Normal+Insert indicates that
the module must appear in the automatic insertion file (for
automatic insertion machines).
This attribute is most useful for
surface mount components (SMDs). -
Virtual indicates that a
component is directly formed by the circuit board. Examples would be
edge connectors or inductances created by a particular track shape
(as sometimes seen in microwave modules).
11.11 - Documenting
modules in a library.
- It is strongly recommended to
document newly created modules, in order to facilitate their rapid
and accurate retrieval.
-
Who is able to recall the multiple
pinout variants of a TO92 module?
-
The Module Properties dialog
offers a simple solution to this problem.

-
It allows:
-
The entry of a comment line
(description).
- Multiple keywords.
- The comment line is displayed
with the component list in CVPCB and in the module selection menus
in PCBNEW.
-
The keywords can be used to restrict
searches to those parts possessing the given keywords.
-
Thus, while using the load module
command (
in the right-hand toolbar in Pcbnew), it is possible to type the
text ''=TO220'' into the dialog box to have PCBNEW display a list of
the modules possessing the keyword ''TO220''.
11.12 - Managing
3-dimensional visualisation
- A module may have associated
with it a file containing a three-dimensional representation of the
component. In order to assocate such a file with a module, select
the 3D Settings tab.
- The options panel is the
following:

-
The follwing information should be
specified:
-
The file containing the 3D
representation (created by the 3D modeller wings3d, in
vrml format, via the export to vrml command).
The default
path is kicad/modules/package3d. In the example, the file
name is discret/to_220horiz.wrl, using the default path) -
The x, y and z scales.
-
The offset with respect to the
anchor point of the module (usually zero).
-
The initial rotation in degrees
about each axis (usually zero).
- If such a file has been
specified, it is possible to view the component in 3D:

-
The 3D model will automatically
appear in the 3D representation of the printed circuit board.
11.13 - Saving
a module to the active library
- The save command (modification
of the file of the active library) is activated by the
icon.-
If a module of the same name exists
(an older version), it will be overwritten.
-
Because it is important to be able
to have confidence in the library modules, it is worth
double-checking the module for errors before saving.
-
Before saving, it is also
recommended to change the reference or value of the module to be
equal to the library name of the module.