Trondheim 21st May 1999.
SINTEF Energy Research (formerly EFI)
Sem Sælandsvei 11
Tlf: +47 73 59 72 00
Fax: +47 73 59 72 50
ATPDraw is a graphical preprocessor to the ATP-EMTP on the MS Windows platform. In the program the user can build up an electric circuit, using the mouse, by selecting predefined components from an extensive palette. Based on the graphical drawing of the circuit, ATPDraw generates the ATP file in the appropriate format based on "what you see is what you get". All kinds of standard circuit editing facilities (copy/paste, grouping, rotate, export/import) are supported. Circuit node naming is administrated by ATPDraw and the user only needs to give name to "key" nodes. More than 65 standard components and 25 TACS objects are available, and in addition the user can create new objects based on MODELS or Data Base Modularization. ATPDraw has a standard Windows layout, supports multiple documents and offers a large Windows help file system, which explains the most basic rules. Other facilities in ATPDraw are: a built-in editor for ATP-file editing, support of Windows clipboard for bitmap/metafile, output of MetaFiles/Bitmaps files or PostScript files not limited to circuit window size, a new module for using Line/Cable Constant punch files directly in ATPDraw, a tool-bar below the main menu containing the most used selections together with the last 9 selected components, an extensive UnDo/ReDo handling with up to 100 steps, etc.
The ATPDraw program is royalty free and can be downloaded free of charge from the ftp server ftp.ee.mtu.edu (user:anonymous, password: your e-mail address). The property of the program belongs to Bonneville Power Administration (BPA) which has financed the program development and the SINTEF Energy Research (SEfAS) former (EFI). The contact person at BPA is Mr. James L. Hall. A User Manual  for the Windows version 1.0 is available on the ftp server (pdf format), direct ordering from SEfAS or the European EMTP Users Group. This manual is co-authored written with Laszlo Prikler at SYSTRAN Engineering Services in Budapest, Hungary.
This WWW-page gives and overview of the facilities in
ATPDraw and a brief explanation on how to build up a circuit. Along with
ATPDraw comes a program called ATP_LCC
which supports Line/Cable Constants in the ATP-EMTP. In this program the
material and geometric data are specified in dialog windows and the cross
section is display in the main window. The program ATP_LCC generates correct
ATP-files which run through ATP produce punch files which in most cases
are readable by ATPDraw. Both PI-circuits, KCLee and JMarti formats are
supported. Cascade PI-circuit punch files are not readable directly by
ATPDraw, however. Help on how to use ATPDraw is best obtained from the
list server or from H.K.
Fig. 1 shows the layout of the ATPDraw 32-bit program executed on a SuperVGA screen (1024x768 pixels) with a circuit windows showing most of the predefined objects.
Figure 1. ATPDraw main windows showing most of the predefined components.
2.1. ATPDraw for Windows
The ATPDraw for Windows program is written in Borland
Delphi 2.0, which is a 32-bit Pascal compiler for Windows 95/NT with
a built-in powerful design editor. The conversion from the old DOS source
code (Borland Pascal 7.0) to Windows has been performed by Odd
Gunnar Dahl at Dahl Data Design in Trondheim. The program is also available
as a version under Delphi 1.0, which creates 16-bit code executable on
Windows 3.1/95/NT. The 32-bit Delphi 2.0 program is better and faster,
and only the 32-bit version is further development.
Four types of objects are available in ATPDraw:
An editor has been created especially tailored to display help files and ATP files (e.g. the line and column number is shown). The user can select his own favorite editor via the Preferences page of the Tools|Options dialog box. ATPDraw supports the standard Windows clipboard format. A new type called ATPDRAW is registered for copying/pasting circuit groups. In addition standard Windows clipboard types are used to copy text (from help file, ATP file, input menus etc.) and circuit pictures. The short commands Ctrl+C (copy) and Ctrl+V (paste) can be used throughout the ATPDraw program. The 32-bit version supports Metafile representation of circuit pictures while the 16-bit version only supports Bitmap (poorer resolution). The Copy as Metafile/Bitmap facility (found under Edit) makes it is possible to zoom out and select a large circuit and copy this picture without the loss of resolution seen on the screen. The Undo/Redo facility has been extensively improved. The DOS version had only a single UnDo step while the Windows version now supports up to 100 UnDo/ReDo steps (10 is default, selectable under Tools|Options) in a very memory efficient way completely without using disk files.
A new module, found at the bottom of the selection menu Overhead line (PCH), has been added to ATPDraw to enable reading of punch files from Line/Cable constants. After selecting a punch file, this file is processed to check the format and a diagnosis is presented to the user. A .LIB file with the same name as the .PCH file is then created automatically (including data base modularization) and a default object is suggested to the user. This module thus makes it possible to include overhead lines and cables efficiently in ATPDraw. The following punch file formats are recognized: KCLee, Clarke, JMarti, Semlyen, and PI-equivalents (several sections not recognized).
A similar module is available for model files diagnosis and automatically creation of corrosponding support files. This module is activated when selecting a model file (extension mod) under MODELS in the selection menu.
An extensive Windows help file is also available under
ATPDraw. This file provides help on all windows and menus in ATPDraw and
how to built up a circuit. Several links between help pages and a relatively
large index register for searching exists. However, little technical information
related to ATP is yet available.
2.2. Line/Cable Constants support
A completely new program called ATP_LCC for Line/Cable Constants support has been written in Borland Delphi 1.0. This program is a 16-bit program executable under Windows 3.1/95/NT. In the ATP_LCC program the user can specify the cross section data and material data for an overhead line or a cable system in input windows. The specified cross section is drawn in the main windows and zooming and export to the windows clipboard is supported. Based on the user specified data the corresponding ATP file is generated ready to be processed by ATP for creation of punched output (punch file) or matrix output (LIS file). The program ATP_LCC consists of two parts; one for Line Constants support and one for Cable Constants. These two parts are handled independently in the program with separate input windows. The program ATP_LCC now supports:
Fig. 2 shows the ATP_LCC program and the Cable Constants input window. A drawing of the cable with an enclosing pipe is shown in the background. A separate input window is available for Line Constants support.
Figure 2. ATP_LCC with Cable Constant support window activated.
2.3. Conversion program
A small program called Convert.exe which converts old DOS version circuit and support files to the new format has also been created. This program is written in Delphi 1.0 and runs under Windows 3.1/95/NT. In this program the user specifies the Windows directory and the DOS directory and which types of files to convert. It is not recommended to convert the support files for standard components.
3. USING ATPDRAW
This chapter lists some of the functionality
in ATPDraw. Much more information is found in the Userís Manual .
Fig. 3 shows the main window in ATPDraw, with some open circuit windows and the Selection menu to the right.
Figure 3. Main window in ATPDraw, showing selection menu at right.
From the Selection menu the user selects components to insert into the circuit. This menu pops up when clicking the right mouse button in an empty area of a circuit window. To select and move an object, simply press and hold down the left mouse button on the object while moving the mouse. Release the button and click in an empty area to unselect and confirm the new position. The object is then moved to the nearest grid point (10 pixels resolution). Overlapping components will produce a warning.
Selected objects or a group can be rotated by clicking on it with the right mouse button. Other object manipulation functions, such as undo/redo and clipboard options can be found in the Edit menu as well as on the tool bar.
Selection of a group of objects for moving can be done in three ways: 1) Holding down the Shift key while left-clicking on an object adds it to the current group. 2) Holding down the left mouse button in an empty area and drag will draw a rectangular outline around the desired objects. 3) Double-clicking the left mouse button in an empty area enables the creation of a polygon shaped region. Corners are created with left button clicks and the region is enclosed with a right click. Objects within the drawn region become a group. An object and a group of objects are moved and edited the same way.
It is possible to draw much larger circuits than shown on the screen in normal zoom mode. The circuit world is 5000x5000 pixels. The user can move around in this world using the window scrollbars or by dragging the view rectangle in the Map Window. The Map Window (shortcut key: M) gives a view of the whole circuit world and a rectangle showing the current circuit window position. Selected objects do not follow the scrollbars or the map window but stay fixed on the screen. Thus, usage of the e.g. scrollbars will move a selected group in the circuit world.
Components and component nodes can be opened for editing. If the user right-click or left double-click on an unselected component or node, either the Component or the Node dialog box will appear where component or node attributes and characteristics can be edited. Click on the Help button to get component specific help, and press F1 to get general help on the dialog box. Default component attributes are stored in support files. Access to create and customise support files is provided under Objects in the main menu. Node names should normally be specified in the Node dialog box, and only nodes of special interest need to be named. ATPDraw handles the whole node naming process.
Components are connected if their nodes overlap or if a connection is drawn between the nodes. To draw a connection between nodes, click on a node with the left mouse button. A line is drawn between that node and the mouse cursor. Click the left mouse button again to place the connection (clicking the right button cancels the operation). The gridsnap facility helps overlapping the nodes. Connected nodes are given the same name by the Make Names and Make File options in the ATP menu. Nodes can be attached along a connection as well as at connection end-points. A connection should not unintentionally cross other nodes (what you see is what you get). A warning for node naming appears during the ATP file creation if a connection exists between nodes of different names, or if the same name has been given to unconnected nodes. Connections can be selected as any other objects. To resize a connection, click on its end-point with the left mouse button, hold down and drag. If several connections share the same node, the desired connection to resize must be selected first. Selected connection nodes are marked with squares at both ends of the selection rectangle. Connections from a 3-phase node are visualised as thick.
Three phase nodes are given the extensions
A/B/C (or D/E/F) automatically by ATPDraw. Rotation of the phase sequence
is possible by usage of special transposition objects. A special
object handles connections between 3-phase and single-phase sub-circuits.
These special objects are found under the Probes&3-phase field
in the Selection menu.
3.2 Main menu contents
Table 1 list the contents of the main menu in ATPDraw.
Tab. 1 Main menu contents
|Main menu field||Contents|
|File||Load and save circuit files, import/export circuit files, create postscript and Metafile/Bitmap files.|
|Edit||Circuit editing; Copy/paste/delete/duplicate, select, move label, copy graphics to clipboard etc.|
|View||Tool bar, status bar and comment line on/off, zoom, refresh, and view options.|
|ATP||Create node names, make ATP file, edit ATP file, ATP file settings (miscellaneous cards and file formats: high/low precision, file sorting etc.). Edit batch jobs and execution of programs/ATP.|
|Objects||Edit support files (default values, min/max limits, icon and help file). Create new support files for Models and User Specified Objects.|
|Tools||Icon editor, help file editor, text editor, options (various program settings).|
|Window||Arranging of the circuit windows. Map window.|
|Help||About box and Windows help file system.|
3.3 Mouse clicks
Tab. 2 contains a summary of the various actions taken dependent on mouse operations. The left mouse button is generally used for selecting objects or connecting nodes; the right mouse button is used for specification of object or node properties.
Tab. 2 Mouse operations in ATPDraw.
- node dialog
|Selection menu +
|Resize connection||Select group
3.4 Give data to components
Clicking on an unselected object with right mouse button
(or left double click) will perform the input window (Open component dialog
box). The input window has almost the same layout for all components.
3.4.1 Ordinary components
An example of an input window is shown in figures 4 and 5. In this window the user must specify the required component data. Click on Help to get help on the specific component and press F1 to get general help on the dialog box functionality. The nonlinear branch components have in addition to the normal Attributes page also a Characteristic page where the nonlinear characteristic and some include file options are specified. (The MOV object is special since an internal arrdat routine is called to perform an exponential fitting of the specified current and voltage points.)
Figure 4. Example of open component dialog box (input window), MOV arrester. Attributes page is common for all components.
Figure 5. Example of open component dialog box (input window), MOV arrester. Characteristic page is special to nonlinear branches.
The Attribute page of the Open Component dialog box in fig. 4, contains besides the DATA and NODE fields (which are explained in the help file, with reference to the RuleBook ), a Group No field (which is used in ATP files sorting), a Label field (written on the screen), a Comment field (written in the ATP-file), an Output group (for branch output request (column 80)) and a Hide button (object not written to ATP-file). Both carriage return, tab or the mouse can be used to move the cursor between input fields. (Exiting the input window by selecting OK will turn off the red color used for the object to indicate that no data has been given. This is selectable under View|Options.)
On the Characteristic page of the Open Component
dialog box in fig. 5, the user specifies a characteristic for non-linear
components. Each new pair of input values is specified in the two fields
at the top of the page. When you press the Enter key in the rightmost field
or select the Insert button, the current input values are transferred
to the table below. To delete from the table, select one or more lines
by pressing and holding down the left mouse button
while you drag the mouse cursor up or down. Release the mouse button and
select the Remove button. The up and down arrow buttons can be used
to change the table position of the currently selected line one step up
or down. The File section at the bottom of the page contains an
where you can specify the name of a standard text file containing input
characteristic values. If the 'Include characteristic' button is checked,
this file will be referenced in an $INCLUDE statement in the ATP file rather
than including each of the value pairs from the points table.
3.4.2 General transformer
A new 3-phase saturable transformer model is added which allows three windings and selection of type of coupling and reluctance. The component dialog box of this transformer is shown in Fig. 6.
Fig. 6. General 3-phase transformer component dialog.
The tertiary winding can be turned on or off by checking
the 3-wind. button. Checking the 3-leg core button turns the transformer
into a TRANSFORMER THREE PHASE type with high homopolar reluctance, which
is specified instead of magnetization losses. Handling of the magnetization
characteristic is equivalent to the older 2-winding transformer components.
Checking the RMS button enables specification of the saturation characteristic
in RMS values for current and voltage on the Characteristic page. A conversion
to flux-current values is performed internally in ATPDraw. If the button
is not checked flux-current values should be entered. Four types of winding
couplings are supported; Wye, Delta lead, Delta lag, and D11. Icons visualize
the selected coupling with red letters indicating the terminal (A, B, and
C) and blue roman numbers indicating the leg number (I, II, and III). Selecting
the Y-coupling the neutral point of the winding becomes available in the
circuit drawing. The internal node of the saturation characteristic is
available outside of the transformer (indicated with red connection).
3.4.3 Universal machines
The handling of electrical machines has been updated substantially. Several universal machines are allowed with global specification of initialization method and interface. Synchronous machine (type 1), two types of induction machines (type 3 & 4), DC machine (type 8) and a single-phase machine (type 6) are supported. The universal machineís component dialog box is shown in fig. 7. The user enters the machine data in five pages. On the General page some general data like stator coupling and the number of d and q axis coils are specified. The Global data are set on the UM page found under ATP|Settings/UM (automatic/manual initialization, compensation/prediction method, SI/pu units). On the Magnet. page the flux/inductance data with saturation are specified. On the Stator and Rotor pages the coil data are given, and under Init the initial conditions.
Fig . 7. Synchronous machine type 3 component dialog.
The General page adapts the selection of machine type. If a DC machine (phase 8) or a single phase machine (type 6) the Stator coupling group is removed. For the other machine types the user can select the type of stator coupling (Y, Dlead, or Dlag). If Y-coupling is specified a neutral node appears in the drawing and a Neut field under Node data as shown in fig. 7 (right). If a induction machine type 4 is selected the Rotor coils group is removed and 0-d-q quatities should be specified under the Rotor page. If a single phase machine (type 6) is selected the number of d-axis coils is fixed to unity. The total number of rotor coils (d- plus q-axis) is restricted to 3 due to memory limitation in the internal ATPDraw data structure (36 data total). The Rotor and Init pages adapt the specification under Rotor coils.
On the Magnet. page the user can specify the saturation
characteristics of the universal machine. LMUD and LMUQ are the unsaturated
common inductance in the d- and q-axis respectively. The type of saturation
can be specified by the radio buttons in the Saturation group. Selecting
None will remove the 6 input fields to the right. The selection symm should
be used for uniform air gaps and in such case only the d-axis values are
enabled (JSATD=5 in Rulebook).
LMSD and LMSQ are the saturated common inductance, FLXRD and FLXRQ are the residual flux at zero current, and FLXSD and FLXSQ are the flux where saturation occurs.
The Stator page is equal for all machine types. On this page the stator winding resistance and inductance are specified in Park transformed quantities (0-d-q system).
The Rotor page adapts the number of rotor coils specified in fig. 7. In this page the resistance and inductance is specified for each rotor coil. First all the d-axis coils is listed then the q-axis coils. A total number of 3 coils is allowed due to memory restrictions in the data structure of ATPDraw. For type 4 induction machines the rotor coils must be specified in Park transformed quantities (0-d-q axis). For this type of machine the Rotor coils group is removed.
The Init page adapts the type of initialization under ATP|Settings/UM. The quantities required for automatic initialization adapt the selected machine type. If manual initialization is selected the current in the stator must be specified in 0-d-q axis quantities along with the current in the various rotor coils (type 4 machine: 0-d-q axis quantities). First the d-axis coils are listed then the q-axis coils, corresponding to the number of rotor coils selected in fig. 6. In addition the initial rotor velocity and position must be specified.
The circuit drawing adapts the specification of stator coupling and initialization automatically. When manual initialization is selected the two source nodes BUSM (torque source) and BUSF (field source is removed). FieldA is the positive node of the field while FieldB is the negative or neutral point.
The universal machine also has a special output group.
TQOUT: 0=nothing, 1=air-gap torque, 2=+d-axis common flux, 3=+d-axis magnetizing current.
OMOUT: 0=nothing, 1=rotor shaft speed, 2=+q-axis common flux, 3=+q-axis magnetizing current.
THOUT: checked= torque angle (elec. rad. for type 1 machines) or rotor position (mech. rad).
CURR: checked=output of all coil currents.
3.4.4 Other types
Some other components have minor different dialog boxes.
These are systematic/statistic switches, harmonic source, type 94 model
components, and general TACS transfer function.
3.5 Node names
Names can be given to all the component's node in the
window in fig. 4, but generally the user has little control here. It is
thus often much better to wait until the circuit construction is finished
before specifying node names. Clicking on a node with the right mouse button
will perform the open node dialog box shown in fig. 8.
|Standard and User Specified Objects||Models and TACS||Synchronous machine nodes|
In the dialog boxes in fig. 8 the user can specify a node name, ground the node or choose to display its name on the screen. Nodes not given names by the user will get default ATPDraw names and are display as red unless the No Data Warning option has been switched off under View|Options. Nodes connected together or overlapping will get the same name automatically (what you see is what you get!!!). If the user specifies two different node names to connected nodes, ATPDraw will make the user aware of this during the ATP-file generation process (compilation). Also nodes not connected together, but given the same name by the user results in a warning during this compilation.
Nodes are connected together in two ways:
The user can select components, give data, perform edit operations in any order. But it is generally advisable for a beginner to let the node naming process be the last step in building up a circuit. This is to avoid undesirable multiple node names (which is corrected by ATPDraw automatically, but still results in irritating warning messages). The user should try to give names to as few nodes as possible. Selecting ATP|Make names will compile the circuit and give ATPDraw names to unspecified nodes (this is also done automatically is ATP|Make file is selected).
ATPDraw also supports 3-phase objects. These are similar
to ordinary single phase objects, except for the handling of node names.
Three-phase nodes have only 5 characters available for the name. The characters
A, B and C (or even D, E and F) are added by ATPDraw. The phase order can
be changed by special transposition objects found under the Probes &
3-phase field in the selection menu. The master node (having phase
sequence ABC or DEF) is determined by placing an ABC reference or
reference object on that particular node. Normal ABC 3-phase circuits
without transposition does not need such object attached. The phase sequence
of the node is written at the bottom of the Open node dialog box (fig.
8) after selecting ATP|Make names or ATP|Make file.
3.6 Creating an ATP-file
The ATP file is created by selecting ATP|Make file. However, the miscellaneous data cards and the file formats must first be specified. This is done under the ATP|Settings. Three miscellaneous data cards are supported; Simulation (dT, Tmax, Xopt and Copt), Integer and Switch cards. Under the File format page the user can select precision mode and ATP-file sorting criteria.
After selecting ATP|Make file the file save dialog box appears where the user must specify an ATP file name (ATPDraw suggests a default name similar to the circuit file or the last file name used). The file generation process is fast, but the node name compilation can take some time.
ATPDraw can not read ATP files. The internal information needed by ATPDraw is stored in a circuit file. Make sure to save the file under File|Save or File|Save as. The ATP settings are stored in the circuit file.
4. ADVANCED USAGE
Besides the standard components, the user can create his own User Specified Objects and use MODELS. This process requires knowledge about Data Base Modularization and the MODELS language respectively. The process normally consists of two steps:
The user can at any time edit standard components with
Component or Objects|Edit TACS.
Available components in ATPDRAW
Usage of MODELS is possible in ATPDRAW. The user can add his own MODELS "procedures" to the program.
This section lists some of the new facilities introduced in ATPDraw since version 1.0 for Windows was launched in June 1997. These are basically improved handling of Models, direct execution of executable and batch files from ATPDraw and new and improved components.
A. Improved handling of MODELS
Version 1.2 of ATPDraw for Windows is capable of reading a mod-file directly, examine its input, output and data variables, and creating an appropriate circuit objects automatically. A mod-file is a text file in the MODELS  language describing the actual model starting with MODEL <ModelName> and ending with ENDMODEL. The mod-file must be stored in <ModelName>.mod. Maximum 12 input+output variables are allowed along with 36 data variables. As default, input nodes are basically positioned on the left side of the icon and the outputs on the right. Indexed variables are not allowed. Below, the header of a mod-file is shown. When reading this file, ATPDraw performs a message box shown in Fig. 9.
V1 -- Voltage on positive side
V2 -- Voltage on negative side
iczn -- Current [Amps]
Pset -- Power setting [MJ/ms]
Eset -- energy setting [MJ]
fdel -- firing delay [ms]
fdur -- firing duration [ms]
power -- power into ZnO [W]
trip -- gap firing signal[0 or 1]
energy -- energy into ZnO [J]
tfire -- prev fire time [s]
vcap -- voltage difference [V]
If the user clicks on Yes in
Fig. 9, left, the edit support file dialog box will appear where the user
primarily can edit the icon, change node positions and set new default
values for input type (current/voltage etc.). If the user selects No,
the default ATPDraw object is drawn in the circuit window directly, as
shown in Fig. 9, right.
Fig. 9. Left: Read .mod file dialog box.
Right: Default model object (flash_1.sup).
Version 1.2 of ATPDraw also supports RECORD of model variables. This option is found under ATP|Settings/Record page as shown in Fig. 10.
In the list box under Model, all models in the active circuit are listed. When selecting a model in this box its variables are listed in the list box under Variable. When selecting a variable here a default alias name appears in Alias. Edit this name and click on Add to record the variable. The Alias name can be changed by selecting an item in the Record list box and type in a new name. The record list is stored in the circuit file, but it does not follow the circuit when using the clipboard or the export group option.
Fig. 10. Record of model variables.
B. Direct execution of ATP/TPPLOT
The user can specify programs to execute directly from ATPDraw. The option is found under ATP|Edit batch jobs as shown in Fig. 11, left. In this window the user can select a name for the batch job (under Name), which file to execute (under Launch file), and what kind of file to send as parameter when calling this program (under Parameter). Selecting Current ATP under Parameter will send the name of the latest generated ATP file as parameter. When selecting File, the user has to specify a file to send when later launching the batch job. The specified batch jobs appear in the main menu under ATP as shown in Fig. 11, right. They are stored in the atpdraw.ini file.
Fig. 11. Left: The Edit batch job window Right: ATP menu.
C. More components
All the older circuit objects of version 1.0 are supported in the new version, but some of them has been removed from the Selection menu and replaced by other more general components. The old objects can still be used in the circuit and are found under User Specified|Files.. in the /SUP or /TAC directories if absolutely required. They are supported internally in ATPDraw and will produce the correct output. Old circuit files will of course still contain these objects. The objects added to ATPDraw in the new version are listed in tab. 3.
Tab. 3. New components in ATPDraw.
|Selection menu||Component file||Icon|
L(i) Type 96
Transp. lines (Ö
1 phase , 3 phase
Cigre load 1/3 ph
Several generalised components have been introduced.
Fig. 12. Type 94 component dialog box.
ATPDraw now supports Harmonic Frequency Scan, as shown in Fig. 13. Under Simulation type the user can switch between time domain, frequency scan, and harmonic (HFS). The various new output formats from ATP is also supported and selectable under Output. A new harmonic source is also introduced with a component dialog box as shown in Fig. 14, along with some new frequency dependent loads.
Fig. 13. Selecting type of simulation.
Fig. 14. Harmonic source component dialog box.
The handling of electrical machines
has been updated substantially. Several universal machines are allowed
with global specification of initialisation method and interface. Synchronous
machine (type 1), two types of induction machines (type 3 & 4), DC
machine (type 8) and a single-phase machine (type 6) are supported. The
user enters the machine data in five pages in the component dialog box.
On the first some general data like stator coupling and the number of d
and q axis coils are specified. The Global data are set under the
page in Fig. 13. On the Magnet. page the flux/inductance data with
saturation are specified. On the Stator and Rotor pages the
coil data are given, and under Init the initial conditions.