480 lines
18 KiB
C++
480 lines
18 KiB
C++
/*
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* This program source code file is part of KICAD, a free EDA CAD application.
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*
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* Copyright (C) 2011 jean-pierre.charras
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* Copyright (C) 1992-2015 Kicad Developers, see change_log.txt for contributors.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, you may find one here:
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* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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* or you may search the http://www.gnu.org website for the version 2 license,
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* or you may write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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/* see
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* http://www.desmith.net/NMdS/Electronics/TraceWidth.html
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* http://www.ultracad.com/articles/pcbtemp.pdf
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* for more info
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*/
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#include <cassert>
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#include <cmath>
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#include <wx/wx.h>
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#include <wx/config.h>
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#include <pcb_calculator_frame_base.h>
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#include <pcb_calculator.h>
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#include <UnitSelector.h>
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#include <units_scales.h>
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extern double DoubleFromString( const wxString& TextValue );
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// Key words to read/write some parameters in config:
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#define KEYWORD_TW_CURRENT wxT( "TW_Track_Current" )
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#define KEYWORD_TW_DELTA_TC wxT( "TW_Delta_TC" )
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#define KEYWORD_TW_TRACK_LEN wxT( "TW_Track_Len" )
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#define KEYWORD_TW_TRACK_LEN_UNIT wxT( "TW_Track_Len_Unit" )
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#define KEYWORD_TW_RESISTIVITY wxT( "TW_Resistivity" )
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#define KEYWORD_TW_EXTTRACK_WIDTH wxT( "TW_ExtTrack_Width" )
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#define KEYWORD_TW_EXTTRACK_WIDTH_UNIT wxT( "TW_ExtTrack_Width_Unit" )
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#define KEYWORD_TW_EXTTRACK_THICKNESS wxT( "TW_ExtTrack_Thickness" )
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#define KEYWORD_TW_EXTTRACK_THICKNESS_UNIT wxT( "TW_ExtTrack_Thickness_Unit" )
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#define KEYWORD_TW_INTTRACK_WIDTH wxT( "TW_IntTrack_Width" )
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#define KEYWORD_TW_INTTRACK_WIDTH_UNIT wxT( "TW_IntTrack_Width_Unit" )
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#define KEYWORD_TW_INTTRACK_THICKNESS wxT( "TW_IntTrack_Thickness" )
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#define KEYWORD_TW_INTTRACK_THICKNESS_UNIT wxT( "TW_IntTrack_Thickness_Unit" )
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void PCB_CALCULATOR_FRAME::TW_WriteConfig( wxConfigBase* aCfg )
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{
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// Save current parameters values in config.
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aCfg->Write( KEYWORD_TW_CURRENT, m_TrackCurrentValue->GetValue() );
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aCfg->Write( KEYWORD_TW_DELTA_TC, m_TrackDeltaTValue->GetValue() );
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aCfg->Write( KEYWORD_TW_TRACK_LEN, m_TrackLengthValue->GetValue() );
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aCfg->Write( KEYWORD_TW_TRACK_LEN_UNIT, m_TW_CuLength_choiceUnit->GetSelection() );
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aCfg->Write( KEYWORD_TW_RESISTIVITY, m_TWResistivity->GetValue() );
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aCfg->Write( KEYWORD_TW_EXTTRACK_WIDTH, m_ExtTrackWidthValue->GetValue() );
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aCfg->Write( KEYWORD_TW_EXTTRACK_WIDTH_UNIT, m_TW_ExtTrackWidth_choiceUnit->GetSelection() );
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aCfg->Write( KEYWORD_TW_EXTTRACK_THICKNESS, m_ExtTrackThicknessValue->GetValue() );
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aCfg->Write( KEYWORD_TW_EXTTRACK_THICKNESS_UNIT, m_ExtTrackThicknessUnit->GetSelection() );
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aCfg->Write( KEYWORD_TW_INTTRACK_WIDTH, m_IntTrackWidthValue->GetValue() );
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aCfg->Write( KEYWORD_TW_INTTRACK_WIDTH_UNIT, m_TW_IntTrackWidth_choiceUnit->GetSelection() );
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aCfg->Write( KEYWORD_TW_INTTRACK_THICKNESS, m_IntTrackThicknessValue->GetValue() );
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aCfg->Write( KEYWORD_TW_INTTRACK_THICKNESS_UNIT, m_IntTrackThicknessUnit->GetSelection() );
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}
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void PCB_CALCULATOR_FRAME::OnTWParametersChanged( wxCommandEvent& event )
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{
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switch(m_TWMode)
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{
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case TW_MASTER_CURRENT:
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OnTWCalculateFromCurrent( event );
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break;
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case TW_MASTER_EXT_WIDTH:
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OnTWCalculateFromExtWidth( event );
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break;
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case TW_MASTER_INT_WIDTH:
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OnTWCalculateFromIntWidth( event );
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break;
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}
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}
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void PCB_CALCULATOR_FRAME::OnTWCalculateFromCurrent( wxCommandEvent& event )
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{
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// Setting the calculated values generates further events. Stop them.
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if( m_TWNested )
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{
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event.StopPropagation();
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return;
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}
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m_TWNested = true;
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// Update state.
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if( m_TWMode != TW_MASTER_CURRENT )
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{
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m_TWMode = TW_MASTER_CURRENT;
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TWUpdateModeDisplay();
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}
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// Prepare parameters:
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double current = std::abs( DoubleFromString( m_TrackCurrentValue->GetValue() ) );
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double extThickness = std::abs( DoubleFromString( m_ExtTrackThicknessValue->GetValue() ) );
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double intThickness = std::abs( DoubleFromString( m_IntTrackThicknessValue->GetValue() ) );
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double deltaT_C = std::abs( DoubleFromString( m_TrackDeltaTValue->GetValue() ) );
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// Normalize by units.
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extThickness *= m_ExtTrackThicknessUnit->GetUnitScale();
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intThickness *= m_IntTrackThicknessUnit->GetUnitScale();
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// Calculate the widths.
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double extTrackWidth = TWCalculateWidth( current, extThickness, deltaT_C, false );
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double intTrackWidth = TWCalculateWidth( current, intThickness, deltaT_C, true );
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// Update the display.
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TWDisplayValues( current, extTrackWidth, intTrackWidth, extThickness, intThickness );
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// Re-enable the events.
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m_TWNested = false;
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}
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void PCB_CALCULATOR_FRAME::OnTWCalculateFromExtWidth( wxCommandEvent& event )
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{
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// Setting the calculated values generates further events. Stop them.
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if( m_TWNested )
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{
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event.StopPropagation();
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return;
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}
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m_TWNested = true;
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// Update state.
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if( m_TWMode != TW_MASTER_EXT_WIDTH )
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{
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m_TWMode = TW_MASTER_EXT_WIDTH;
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TWUpdateModeDisplay();
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}
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// Load parameters.
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double current;
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double extThickness = std::abs( DoubleFromString( m_ExtTrackThicknessValue->GetValue() ) );
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double intThickness = std::abs( DoubleFromString( m_IntTrackThicknessValue->GetValue() ) );
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double deltaT_C = std::abs( DoubleFromString( m_TrackDeltaTValue->GetValue() ) );
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double extTrackWidth = std::abs( DoubleFromString( m_ExtTrackWidthValue->GetValue() ) );
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double intTrackWidth;
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// Normalize units.
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extThickness *= m_ExtTrackThicknessUnit->GetUnitScale();
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intThickness *= m_IntTrackThicknessUnit->GetUnitScale();
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extTrackWidth *= m_TW_ExtTrackWidth_choiceUnit->GetUnitScale();
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// Calculate the maximum current.
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current = TWCalculateCurrent( extTrackWidth, extThickness, deltaT_C, false );
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// And now calculate the corresponding internal width.
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intTrackWidth = TWCalculateWidth( current, intThickness, deltaT_C, true );
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// Update the display.
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TWDisplayValues( current, extTrackWidth, intTrackWidth, extThickness, intThickness );
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// Re-enable the events.
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m_TWNested = false;
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}
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void PCB_CALCULATOR_FRAME::OnTWCalculateFromIntWidth( wxCommandEvent& event )
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{
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// Setting the calculated values generates further events. Stop them.
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if( m_TWNested )
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{
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event.StopPropagation();
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return;
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}
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m_TWNested = true;
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// Update state.
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if( m_TWMode != TW_MASTER_INT_WIDTH )
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{
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m_TWMode = TW_MASTER_INT_WIDTH;
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TWUpdateModeDisplay();
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}
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// Load parameters.
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double current;
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double extThickness = std::abs( DoubleFromString( m_ExtTrackThicknessValue->GetValue() ) );
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double intThickness = std::abs( DoubleFromString( m_IntTrackThicknessValue->GetValue() ) );
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double deltaT_C = std::abs( DoubleFromString( m_TrackDeltaTValue->GetValue() ) );
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double extTrackWidth;
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double intTrackWidth = std::abs( DoubleFromString( m_IntTrackWidthValue->GetValue() ) );
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// Normalize units.
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extThickness *= m_ExtTrackThicknessUnit->GetUnitScale();
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intThickness *= m_IntTrackThicknessUnit->GetUnitScale();
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intTrackWidth *= m_TW_IntTrackWidth_choiceUnit->GetUnitScale();
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// Calculate the maximum current.
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current = TWCalculateCurrent( intTrackWidth, intThickness, deltaT_C, true );
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// And now calculate the corresponding external width.
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extTrackWidth = TWCalculateWidth( current, extThickness, deltaT_C, false );
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// Update the display.
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TWDisplayValues( current, extTrackWidth, intTrackWidth, extThickness, intThickness );
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// Re-enable the events.
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m_TWNested = false;
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}
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void PCB_CALCULATOR_FRAME::TWDisplayValues( double aCurrent, double aExtWidth,
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double aIntWidth, double aExtThickness, double aIntThickness )
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{
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wxString msg;
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// Show the current.
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if( m_TWMode != TW_MASTER_CURRENT )
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{
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msg.Printf( wxT( "%g" ), aCurrent );
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m_TrackCurrentValue->SetValue( msg );
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}
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// Load scale factors to convert into output units.
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double extScale = m_TW_ExtTrackWidth_choiceUnit->GetUnitScale();
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double intScale = m_TW_IntTrackWidth_choiceUnit->GetUnitScale();
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// Display the widths.
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if( m_TWMode != TW_MASTER_EXT_WIDTH )
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{
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msg.Printf( wxT( "%g" ), aExtWidth / extScale );
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m_ExtTrackWidthValue->SetValue( msg );
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}
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if( m_TWMode != TW_MASTER_INT_WIDTH )
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{
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msg.Printf( wxT( "%g" ), aIntWidth / intScale );
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m_IntTrackWidthValue->SetValue( msg );
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}
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// Display cross-sectional areas.
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msg.Printf( wxT( "%g" ), (aExtWidth * aExtThickness) / (extScale * extScale) );
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m_ExtTrackAreaValue->SetLabel( msg );
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msg.Printf( wxT( "%g" ), (aIntWidth * aIntThickness) / (intScale * intScale) );
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m_IntTrackAreaValue->SetLabel( msg );
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// Show area units.
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wxString strunit = m_TW_ExtTrackWidth_choiceUnit->GetUnitName();
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msg = strunit + wxT( " x " ) + strunit;
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m_ExtTrackAreaUnitLabel->SetLabel( msg );
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strunit = m_TW_IntTrackWidth_choiceUnit->GetUnitName();
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msg = strunit + wxT( " x " ) + strunit;
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m_IntTrackAreaUnitLabel->SetLabel( msg );
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// Load resistivity and length of traces.
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double rho = std::abs( DoubleFromString( m_TWResistivity->GetValue() ) );
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double trackLen = std::abs( DoubleFromString( m_TrackLengthValue->GetValue() ) );
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trackLen *= m_TW_CuLength_choiceUnit->GetUnitScale();
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// Calculate resistance.
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double extResistance = ( rho * trackLen ) / ( aExtWidth * aExtThickness );
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double intResistance = ( rho * trackLen ) / ( aIntWidth * aIntThickness );
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// Display resistance.
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msg.Printf( wxT( "%g" ), extResistance );
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m_ExtTrackResistValue->SetLabel( msg );
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msg.Printf( wxT( "%g" ), intResistance );
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m_IntTrackResistValue->SetLabel( msg );
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// Display voltage drop along trace.
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double extV = extResistance * aCurrent;
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msg.Printf( wxT( "%g" ), extV );
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m_ExtTrackVDropValue->SetLabel( msg );
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double intV = intResistance * aCurrent;
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msg.Printf( wxT( "%g" ), intV );
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m_IntTrackVDropValue->SetLabel( msg );
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// And power loss.
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msg.Printf( wxT( "%g" ), extV * aCurrent );
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m_ExtTrackLossValue->SetLabel( msg );
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msg.Printf( wxT( "%g" ), intV * aCurrent );
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m_IntTrackLossValue->SetLabel( msg );
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}
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void PCB_CALCULATOR_FRAME::TWUpdateModeDisplay()
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{
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wxFont labelfont;
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wxFont controlfont;
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// Set the font weight of the current.
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labelfont = m_staticTextCurrent->GetFont();
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controlfont = m_TrackCurrentValue->GetFont();
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if( m_TWMode == TW_MASTER_CURRENT )
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{
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labelfont.SetWeight( wxFONTWEIGHT_BOLD );
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controlfont.SetWeight( wxFONTWEIGHT_BOLD );
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}
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else
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{
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labelfont.SetWeight( wxFONTWEIGHT_NORMAL );
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controlfont.SetWeight( wxFONTWEIGHT_NORMAL );
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}
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m_staticTextCurrent->SetFont( labelfont );
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m_TrackCurrentValue->SetFont( controlfont );
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// Set the font weight of the external track width.
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labelfont = m_staticTextExtWidth->GetFont();
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controlfont = m_ExtTrackWidthValue->GetFont();
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if( m_TWMode == TW_MASTER_EXT_WIDTH )
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{
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labelfont.SetWeight( wxFONTWEIGHT_BOLD );
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controlfont.SetWeight( wxFONTWEIGHT_BOLD );
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}
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else
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{
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labelfont.SetWeight( wxFONTWEIGHT_NORMAL );
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controlfont.SetWeight( wxFONTWEIGHT_NORMAL );
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}
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m_staticTextExtWidth->SetFont( labelfont );
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m_ExtTrackWidthValue->SetFont( controlfont );
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// Set the font weight of the internal track width.
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labelfont = m_staticTextIntWidth->GetFont();
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controlfont = m_IntTrackWidthValue->GetFont();
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if( m_TWMode == TW_MASTER_INT_WIDTH )
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{
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labelfont.SetWeight( wxFONTWEIGHT_BOLD );
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controlfont.SetWeight( wxFONTWEIGHT_BOLD );
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}
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else
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{
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labelfont.SetWeight( wxFONTWEIGHT_NORMAL );
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controlfont.SetWeight( wxFONTWEIGHT_NORMAL );
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}
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m_staticTextIntWidth->SetFont( labelfont );
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m_IntTrackWidthValue->SetFont( controlfont );
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// Text sizes have changed when the font weight was changes
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// So, run the page layout to reflect the changes
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wxWindow* page = m_Notebook->GetPage ( 1 );
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page->GetSizer()->Layout();
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}
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/* calculate track width for external or internal layers
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*
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* Imax = 0.048 * dT^0.44 * A^0.725 for external layer
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* Imax = 0.024 * dT^0.44 * A^0.725 for internal layer
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* with A = area = aThickness * trackWidth ( in mils )
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* and dT = temperature rise in degree C
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* Of course we want to know trackWidth
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*/
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double PCB_CALCULATOR_FRAME::TWCalculateWidth( double aCurrent, double aThickness, double aDeltaT_C,
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bool aUseInternalLayer )
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{
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// Appropriate scale for requested layer.
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double scale = aUseInternalLayer ? 0.024 : 0.048;
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// aThickness is given in normalize units (in meters) and we need mil
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aThickness /= UNIT_MIL;
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/* formula is Imax = scale * dT^0.44 * A^0.725
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* or
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* log(Imax) = log(scale) + 0.44*log(dT)
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* +(0.725*(log(aThickness) + log(trackWidth))
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* log(trackWidth) * 0.725 = log(Imax) - log(scale) - 0.44*log(dT) - 0.725*log(aThickness)
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*/
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double dtmp = log( aCurrent ) - log( scale ) - 0.44 * log( aDeltaT_C ) - 0.725 * log( aThickness );
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dtmp /= 0.725;
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double trackWidth = exp( dtmp );
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trackWidth *= UNIT_MIL; // We are using normalize units (sizes in meters) and we have mil
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return trackWidth; // in meters
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}
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double PCB_CALCULATOR_FRAME::TWCalculateCurrent( double aWidth, double aThickness, double aDeltaT_C,
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bool aUseInternalLayer )
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{
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// Appropriate scale for requested layer.
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double scale = aUseInternalLayer ? 0.024 : 0.048;
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// Convert thickness and width to mils.
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aThickness /= UNIT_MIL;
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aWidth /= UNIT_MIL;
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double area = aThickness * aWidth;
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double current = scale * pow( aDeltaT_C, 0.44 ) * pow( area, 0.725 );
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return current;
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}
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void PCB_CALCULATOR_FRAME::TW_Init( wxConfigBase* aCfg )
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{
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int tmp;
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wxString msg;
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// Disable calculations while we initialise.
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m_TWNested = true;
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// Read parameter values.
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aCfg->Read( KEYWORD_TW_CURRENT, &msg, wxT( "1.0" ) );
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m_TrackCurrentValue->SetValue( msg );
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aCfg->Read( KEYWORD_TW_DELTA_TC, &msg, wxT( "10.0" ) );
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m_TrackDeltaTValue->SetValue( msg );
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aCfg->Read( KEYWORD_TW_TRACK_LEN, &msg, wxT( "20" ) );
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m_TrackLengthValue->SetValue( msg );
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aCfg->Read( KEYWORD_TW_TRACK_LEN_UNIT, &tmp, 0 );
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m_TW_CuLength_choiceUnit->SetSelection( tmp );
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aCfg->Read( KEYWORD_TW_RESISTIVITY, &msg, wxT( "1.72e-8" ) );
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m_TWResistivity->SetValue( msg );
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aCfg->Read( KEYWORD_TW_EXTTRACK_WIDTH, &msg, wxT( "0.2" ) );
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m_ExtTrackWidthValue->SetValue( msg );
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aCfg->Read( KEYWORD_TW_EXTTRACK_WIDTH_UNIT, &tmp, 0 );
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m_TW_ExtTrackWidth_choiceUnit->SetSelection( tmp );
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aCfg->Read( KEYWORD_TW_EXTTRACK_THICKNESS, &msg, wxT( "0.035" ) );
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m_ExtTrackThicknessValue->SetValue( msg );
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aCfg->Read( KEYWORD_TW_EXTTRACK_THICKNESS_UNIT, &tmp, 0 );
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m_ExtTrackThicknessUnit->SetSelection( tmp );
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aCfg->Read( KEYWORD_TW_INTTRACK_WIDTH, &msg, wxT( "0.2" ) );
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m_IntTrackWidthValue->SetValue( msg );
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aCfg->Read( KEYWORD_TW_INTTRACK_WIDTH_UNIT, &tmp, 0 );
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m_TW_IntTrackWidth_choiceUnit->SetSelection( tmp );
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aCfg->Read( KEYWORD_TW_INTTRACK_THICKNESS, &msg, wxT( "0.035" ) );
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m_IntTrackThicknessValue->SetValue( msg );
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aCfg->Read( KEYWORD_TW_INTTRACK_THICKNESS_UNIT, &tmp, 0 );
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m_IntTrackThicknessUnit->SetSelection( tmp );
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// Init formulas text
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msg = "<br>";
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msg << _( "If you specify the maximum current, then the trace "
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"widths will be calculated to suit." )
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<< "<br>" << _( "If you specify one of the trace widths, the maximum "
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"current it can handle will be calculated. The width "
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"for the other trace to also handle this current will "
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"then be calculated." )
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<< "<br>" << _( "The controlling value is shown in bold." ) << "<br><br>"
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<< _( "The calculations are valid for currents up to 35A "
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"(external) or 17.5A (internal), temperature rises "
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"up to 100 deg C, and widths of up to 400mil (10mm)." )<< "<br>"
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<< _( "The formula, from IPC 2221, is" )
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<< "<center><b>I = K * dT<sup>0.44</sup> * (W*H)<sup>0.725</sup></b></center>"
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<< _( "where:" ) << "<br><b>I</b> = "
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<< _( "maximum current in amps" )
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<< "<br><b>dT</b> = "
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<< _( "temperature rise above ambient in deg C" )
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<< "<br><b>W,H</b> = "
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<< _( "width and thickness in mils" ) << "<br>"
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<< "<b>K</b> = "
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<< _( "0.024 for internal traces or 0.048 for external traces" );
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m_htmlWinFormulas->AppendToPage( msg );
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// Make sure the correct master mode is displayed.
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TWUpdateModeDisplay();
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// Enable calculations and perform the initial one.
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m_TWNested = false;
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wxCommandEvent dummy;
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OnTWParametersChanged( dummy );
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}
|