src/Instrumentation/vertical_speed_indicator.cxx

   1 // vertical_speed_indicator.cxx - a regular VSI.
   2 // Written by David Megginson, started 2002.
   3 //
   4 // This file is in the Public Domain and comes with no warranty.
   5
   6 #include <simgear/math/interpolater.hxx>
   7
   8 #include "vertical_speed_indicator.hxx"
   9 #include <Main/fg_props.hxx>
  10 #include <Main/util.hxx>
  11
  12
  13 VerticalSpeedIndicator::VerticalSpeedIndicator ( SGPropertyNode *node )
  14     : _internal_pressure_inhg(29.92),
  15       name("vertical-speed-indicator"),
  16       num(0),
  17       static_port("/systems/static")
  18 {
  19     int i;
  20     for ( i = 0; i < node->nChildren(); ++i ) {
  21         SGPropertyNode *child = node->getChild(i);
  22         string cname = child->getName();
  23         string cval = child->getStringValue();
  24         if ( cname == "name" ) {
  25             name = cval;
  26         } else if ( cname == "number" ) {
  27             num = child->getIntValue();
  28         } else if ( cname == "static-port" ) {
  29             static_port = cval;
  30         } else {
  31             SG_LOG( SG_INSTR, SG_WARN, "Error in vertical-speed-indicator config logic" );
  32             if ( name.length() ) {
  33                 SG_LOG( SG_INSTR, SG_WARN, "Section = " << name );
  34             }
  35         }
  36     }
  37 }
  38
  39 VerticalSpeedIndicator::VerticalSpeedIndicator ()
  40     : _internal_pressure_inhg(29.92)
  41 {
  42 }
  43
  44 VerticalSpeedIndicator::~VerticalSpeedIndicator ()
  45 {
  46 }
  47
  48 void
  49 VerticalSpeedIndicator::init ()
  50 {
  51     string branch;
  52     branch = "/instrumentation/" + name;
  53     static_port += "/pressure-inhg";
  54
  55     SGPropertyNode *node = fgGetNode(branch.c_str(), num, true );
  56     _serviceable_node = node->getChild("serviceable", 0, true);
  57     _pressure_node = fgGetNode(static_port.c_str(), true);
  58     _speed_node = node->getChild("indicated-speed-fpm", 0, true);
  59
  60                                 // Initialize at ambient pressure
  61     _internal_pressure_inhg = _pressure_node->getDoubleValue();
  62 }
  63
  64 void
  65 VerticalSpeedIndicator::update (double dt)
  66 {
  67                                 // model taken from steam.cxx, with change
  68                                 // from 10000 to 10500 for manual factor
  69     if (_serviceable_node->getBoolValue()) {
  70         double pressure = _pressure_node->getDoubleValue();
  71         _speed_node
  72             ->setDoubleValue((_internal_pressure_inhg - pressure) * 10500);
  73         _internal_pressure_inhg =
  74             fgGetLowPass(_internal_pressure_inhg,
  75                          _pressure_node->getDoubleValue(),
  76                          dt/6.0);
  77     }
  78 }
  79
  80 // end of vertical_speed_indicator.cxx