67b8af5ea2
From the c172p-team https://github.com/c172p-team/c172p/releases/tag/version%2F2020.1 Commit 5c870e4559434393c6985ae8ae4c11132a3d2030
542 lines
16 KiB
Text
542 lines
16 KiB
Text
##
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# Procedural model of a Cessna 172S electrical system. Includes a
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# preliminary battery charge/discharge model and realistic ammeter
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# gauge modeling.
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#
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##
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# Initialize internal values
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#
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var vbus_volts = 0.0;
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var ebus1_volts = 0.0;
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var ebus2_volts = 0.0;
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var ammeter_ave = 0.0;
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##
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# Battery model class.
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#
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var BatteryClass = {};
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BatteryClass.new = func {
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var obj = { parents : [BatteryClass],
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ideal_volts : 24.0,
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ideal_amps : 30.0,
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amp_hours : 3.1875,
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charge_percent : getprop("/systems/electrical/battery-charge-percent") or 1.0,
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charge_amps : 7.0 };
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setprop("/systems/electrical/battery-charge-percent", obj.charge_percent);
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return obj;
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}
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##
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# Passing in positive amps means the battery will be discharged.
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# Negative amps indicates a battery charge.
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#
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BatteryClass.apply_load = func (amps, dt) {
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var old_charge_percent = getprop("/systems/electrical/battery-charge-percent");
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if (getprop("/sim/freeze/replay-state"))
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return me.amp_hours * old_charge_percent;
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var amphrs_used = amps * dt / 3600.0;
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var percent_used = amphrs_used / me.amp_hours;
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var new_charge_percent = std.max(0.0, std.min(old_charge_percent - percent_used, 1.0));
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if (new_charge_percent < 0.1 and old_charge_percent >= 0.1)
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gui.popupTip("Warning: Low battery! Enable alternator or apply external power to recharge battery!", 10);
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me.charge_percent = new_charge_percent;
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setprop("/systems/electrical/battery-charge-percent", new_charge_percent);
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return me.amp_hours * new_charge_percent;
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}
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##
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# Return output volts based on percent charged. Currently based on a simple
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# polynomial percent charge vs. volts function.
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#
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BatteryClass.get_output_volts = func {
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var x = 1.0 - me.charge_percent;
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var tmp = -(3.0 * x - 1.0);
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var factor = (tmp*tmp*tmp*tmp*tmp + 32) / 32;
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return me.ideal_volts * factor;
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}
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##
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# Return output amps available. This function is totally wrong and should be
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# fixed at some point with a more sensible function based on charge percent.
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# There is probably some physical limits to the number of instantaneous amps
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# a battery can produce (cold cranking amps?)
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#
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BatteryClass.get_output_amps = func {
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var x = 1.0 - me.charge_percent;
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var tmp = -(3.0 * x - 1.0);
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var factor = (tmp*tmp*tmp*tmp*tmp + 32) / 32;
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return me.ideal_amps * factor;
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}
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##
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# Set the current charge instantly to 100 %.
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#
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BatteryClass.reset_to_full_charge = func {
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me.apply_load(-(1.0 - me.charge_percent) * me.amp_hours, 3600);
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}
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##
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# Alternator model class.
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#
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var AlternatorClass = {};
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AlternatorClass.new = func {
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var obj = { parents : [AlternatorClass],
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rpm_source : "/engines/active-engine/rpm",
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rpm_threshold : 800.0,
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ideal_volts : 28.0,
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ideal_amps : 60.0 };
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setprop( obj.rpm_source, 0.0 );
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return obj;
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}
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##
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# Computes available amps and returns remaining amps after load is applied
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#
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AlternatorClass.apply_load = func( amps, dt ) {
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# Scale alternator output for rpms < 800. For rpms >= 800
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# give full output. This is just a WAG, and probably not how
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# it really works but I'm keeping things "simple" to start.
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var rpm = getprop( me.rpm_source );
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var factor = rpm / me.rpm_threshold;
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if ( factor > 1.0 ) {
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factor = 1.0;
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}
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# print( "alternator amps = ", me.ideal_amps * factor );
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var available_amps = me.ideal_amps * factor;
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return available_amps - amps;
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}
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##
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# Return output volts based on rpm
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#
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AlternatorClass.get_output_volts = func {
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# scale alternator output for rpms < 800. For rpms >= 800
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# give full output. This is just a WAG, and probably not how
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# it really works but I'm keeping things "simple" to start.
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var rpm = getprop( me.rpm_source );
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var factor = rpm / me.rpm_threshold;
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if ( factor > 1.0 ) {
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factor = 1.0;
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}
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# print( "alternator volts = ", me.ideal_volts * factor );
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return me.ideal_volts * factor;
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}
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##
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# Return output amps available based on rpm.
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#
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AlternatorClass.get_output_amps = func {
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# scale alternator output for rpms < 800. For rpms >= 800
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# give full output. This is just a WAG, and probably not how
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# it really works but I'm keeping things "simple" to start.
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var rpm = getprop( me.rpm_source );
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var factor = rpm / me.rpm_threshold;
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if ( factor > 1.0 ) {
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factor = 1.0;
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}
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# print( "alternator amps = ", ideal_amps * factor );
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return me.ideal_amps * factor;
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}
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var battery = BatteryClass.new();
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var alternator = AlternatorClass.new();
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var reset_battery_and_circuit_breakers = func {
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# Charge battery to 100 %
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battery.reset_to_full_charge();
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# Reset circuit breakers
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setprop("/controls/circuit-breakers/master", 1);
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setprop("/controls/circuit-breakers/flaps", 1);
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setprop("/controls/circuit-breakers/pitot-heat", 1);
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setprop("/controls/circuit-breakers/instr", 1);
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setprop("/controls/circuit-breakers/intlt", 1);
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setprop("/controls/circuit-breakers/navlt", 1);
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setprop("/controls/circuit-breakers/landing", 1);
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setprop("/controls/circuit-breakers/bcnlt", 1);
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setprop("/controls/circuit-breakers/strobe", 1);
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setprop("/controls/circuit-breakers/turn-coordinator", 1);
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setprop("/controls/circuit-breakers/radio1", 1);
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setprop("/controls/circuit-breakers/radio2", 1);
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setprop("/controls/circuit-breakers/radio3", 1);
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setprop("/controls/circuit-breakers/radio4", 1);
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setprop("/controls/circuit-breakers/radio5", 1);
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setprop("/controls/circuit-breakers/autopilot", 1);
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if (getprop("/fdm/jsbsim/bushkit") == 4) {
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setprop("/controls/circuit-breakers/gear-select", 1);
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setprop("/controls/circuit-breakers/gear-advisory", 1);
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setprop("/controls/circuit-breakers/hydraulic-pump", 1);
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}
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}
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##
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# This is the main electrical system update function.
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#
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var ElectricalSystemUpdater = {
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new : func {
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var m = {
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parents: [ElectricalSystemUpdater]
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};
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# Request that the update function be called each frame
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m.loop = updateloop.UpdateLoop.new(components: [m], update_period: 0.0, enable: 0);
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return m;
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},
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enable: func {
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me.loop.reset();
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me.loop.enable();
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},
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disable: func {
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me.loop.disable();
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},
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reset: func {
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# Do nothing
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},
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update: func (dt) {
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update_virtual_bus(dt);
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}
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};
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##
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# Model the system of relays and connections that join the battery,
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# alternator, starter, master/alt switches, external power supply.
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#
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var update_virtual_bus = func (dt) {
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var serviceable = getprop("/systems/electrical/serviceable");
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var external_volts = 0.0;
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var load = 0.0;
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var battery_volts = 0.0;
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var alternator_volts = 0.0;
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if ( serviceable ) {
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battery_volts = battery.get_output_volts();
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alternator_volts = alternator.get_output_volts();
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}
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# switch state
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var master_bat = getprop("/controls/switches/master-bat");
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var master_alt = getprop("/controls/switches/master-alt");
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if (getprop("/controls/electric/external-power"))
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{
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external_volts = 28;
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}
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# determine power source
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var bus_volts = 0.0;
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var power_source = nil;
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if ( master_bat ) {
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bus_volts = battery_volts;
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power_source = "battery";
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}
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if ( master_alt and (alternator_volts > bus_volts) ) {
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bus_volts = alternator_volts;
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power_source = "alternator";
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}
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if ( external_volts > bus_volts ) {
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bus_volts = external_volts;
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power_source = "external";
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}
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#print( "virtual bus volts = ", bus_volts );
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# bus network (1. these must be called in the right order, 2. the
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# bus routine itself determins where it draws power from.)
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load += electrical_bus_1();
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load += avionics_bus_1();
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# swtich the master breaker off if load is out of limits
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if ( load > 55 ) {
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bus_volts = 0;
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}
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# system loads and ammeter gauge
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var ammeter = 0.0;
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if ( bus_volts > 1.0 ) {
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# ammeter gauge
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if ( power_source == "battery" ) {
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ammeter = -load;
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} else {
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ammeter = battery.charge_amps;
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}
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}
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# print( "ammeter = ", ammeter );
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# charge/discharge the battery
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if ( power_source == "battery" ) {
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battery.apply_load( load, dt );
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} elsif ( bus_volts > battery_volts ) {
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battery.apply_load( -battery.charge_amps, dt );
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}
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# filter ammeter needle pos
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ammeter_ave = 0.8 * ammeter_ave + 0.2 * ammeter;
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# outputs
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setprop("/systems/electrical/amps", ammeter_ave);
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setprop("/systems/electrical/volts", bus_volts);
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if (bus_volts > 12)
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vbus_volts = bus_volts;
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else
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vbus_volts = 0.0;
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return load;
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}
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var electrical_bus_1 = func() {
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var bus_volts = 0.0;
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var load = 0.0;
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# check master breaker
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if ( getprop("/controls/circuit-breakers/master") ) {
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# we are feed from the virtual bus
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bus_volts = vbus_volts;
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}
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#print("Bus volts: ", bus_volts);
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# Air-cond
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if ( getprop("/controls/circuit-breakers/aircond-pwr") ) {
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setprop("/systems/electrical/outputs/aircond", bus_volts);
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load += bus_volts / 57;
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} else {
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setprop("/systems/electrical/outputs/aircond", 0.0);
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}
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# Flaps
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if ( getprop("/controls/circuit-breakers/flaps") ) {
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setprop("/systems/electrical/outputs/flaps", bus_volts);
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load += bus_volts / 57;
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} else {
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setprop("/systems/electrical/outputs/flaps", 0.0);
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}
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# Pitot Heat Power
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if ( getprop("/controls/anti-ice/pitot-heat" ) ) {
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setprop("/systems/electrical/outputs/pitot-heat", bus_volts);
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load += bus_volts / 28;
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} else {
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setprop("/systems/electrical/outputs/pitot-heat", 0.0);
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}
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# Instrument Power: ignition, fuel, oil temperature
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if ( getprop("/controls/circuit-breakers/instr") ) {
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setprop("/systems/electrical/outputs/instr-ignition-switch", bus_volts);
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if ( bus_volts > 12 ) {
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# starter
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if ( getprop("controls/switches/starter") ) {
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setprop("systems/electrical/outputs/starter", bus_volts);
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load += 24;
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} else {
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setprop("systems/electrical/outputs/starter", 0.0);
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}
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load += bus_volts / 57;
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} else {
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setprop("systems/electrical/outputs/starter", 0.0);
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}
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} else {
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setprop("/systems/electrical/outputs/instr-ignition-switch", 0.0);
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setprop("/systems/electrical/outputs/starter", 0.0);
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}
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# Interior lights
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if ( getprop("/controls/circuit-breakers/intlt") ) {
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setprop("/systems/electrical/outputs/instrument-lights", bus_volts);
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setprop("/systems/electrical/outputs/cabin-lights", bus_volts);
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load += bus_volts / 57;
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} else {
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setprop("/systems/electrical/outputs/instrument-lights", 0.0);
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setprop("/systems/electrical/outputs/cabin-lights", 0.0);
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}
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# Landing Light Power
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if ( getprop("/controls/circuit-breakers/landing") and getprop("/controls/lighting/landing-lights") ) {
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setprop("/systems/electrical/outputs/landing-lights", bus_volts);
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load += bus_volts / 5;
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} else {
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setprop("/systems/electrical/outputs/landing-lights", 0.0 );
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}
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# Taxi Lights Power
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# Notice taxi lights also use landing lights breaker. It is not a bug.
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if ( getprop("/controls/circuit-breakers/landing") and getprop("/controls/lighting/taxi-light" ) ) {
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setprop("/systems/electrical/outputs/taxi-light", bus_volts);
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load += bus_volts / 10;
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} else {
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setprop("/systems/electrical/outputs/taxi-light", 0.0);
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}
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# Beacon Power
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if ( getprop("/controls/circuit-breakers/bcnlt") and getprop("/controls/lighting/beacon" ) ) {
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setprop("/systems/electrical/outputs/beacon", bus_volts);
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load += bus_volts / 28;
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} else {
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setprop("/systems/electrical/outputs/beacon", 0.0);
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}
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# Nav Lights Power
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if ( getprop("/controls/circuit-breakers/navlt") and getprop("/controls/lighting/nav-lights" ) ) {
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setprop("/systems/electrical/outputs/nav-lights", bus_volts);
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load += bus_volts / 14;
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} else {
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setprop("/systems/electrical/outputs/nav-lights", 0.0);
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}
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# Strobe Lights Power
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if ( getprop("/controls/circuit-breakers/strobe") and getprop("/controls/lighting/strobe" ) ) {
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setprop("/systems/electrical/outputs/strobe", bus_volts);
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setprop("/systems/electrical/outputs/strobe-norm", (bus_volts/24));
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load += bus_volts / 14;
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} else {
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setprop("/systems/electrical/outputs/strobe", 0.0);
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setprop("/systems/electrical/outputs/strobe-norm", 0.0);
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}
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# Turn Coordinator and directional gyro Power
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if ( getprop("/controls/circuit-breakers/turn-coordinator") ) {
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setprop("/systems/electrical/outputs/turn-coordinator", bus_volts);
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setprop("/systems/electrical/outputs/DG", bus_volts);
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load += bus_volts / 14;
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} else {
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setprop("/systems/electrical/outputs/turn-coordinator", 0.0);
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setprop("/systems/electrical/outputs/DG", 0.0);
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}
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# Gear Select Power
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if ( getprop("/controls/circuit-breakers/gear-select") ) {
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setprop("/systems/electrical/outputs/gear-select", bus_volts);
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load += bus_volts / 5;
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} else {
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setprop("/systems/electrical/outputs/gear-select", 0.0);
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}
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# Gear Advisory Power
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if ( getprop("/controls/circuit-breakers/gear-advisory") ) {
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setprop("/systems/electrical/outputs/gear-advisory", bus_volts);
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load += bus_volts / 2;
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} else {
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setprop("/systems/electrical/outputs/gear-advisory", 0.0);
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}
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# Hydraulic Pump Power
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if ( getprop("/controls/circuit-breakers/hydraulic-pump") ) {
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setprop("/systems/electrical/outputs/hydraulic-pump", bus_volts);
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load += bus_volts / 40;
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} else {
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setprop("/systems/electrical/outputs/hydraulic-pump", 0.0);
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}
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# register bus voltage
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ebus1_volts = bus_volts;
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# return cumulative load
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return load;
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}
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var avionics_bus_1 = func() {
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var bus_volts = 0.0;
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var load = 0.0;
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# we are fed from the electrical bus 1
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var master_av = getprop("/controls/switches/master-avionics");
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if ( master_av ) {
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bus_volts = ebus1_volts;
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}
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load += bus_volts / 20.0;
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# Avionics Fan Power
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#setprop("/systems/electrical/outputs/avionics-fan", bus_volts);
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# Audio Panel 1 Power
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if ( getprop("/controls/circuit-breakers/radio1") ) {
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setprop("/systems/electrical/outputs/audio-panel[0]", bus_volts);
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} else {
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setprop("/systems/electrical/outputs/audio-panel[0]", 0.0);
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}
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# Com and Nav 1 Power
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if ( getprop("/controls/circuit-breakers/radio2") ) {
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setprop("/systems/electrical/outputs/nav[0]", bus_volts);
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setprop("systems/electrical/outputs/comm[0]", bus_volts);
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} else {
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setprop("/systems/electrical/outputs/nav[0]", 0.0);
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setprop("systems/electrical/outputs/comm[0]", 0.0);
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}
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# Com and Nav 2 Power
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if ( getprop("/controls/circuit-breakers/radio3") ) {
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setprop("/systems/electrical/outputs/nav[1]", bus_volts);
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setprop("systems/electrical/outputs/comm[1]", bus_volts);
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} else {
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setprop("/systems/electrical/outputs/nav[1]", 0.0);
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setprop("systems/electrical/outputs/comm[1]", 0.0);
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}
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# Transponder Power
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if ( getprop("/controls/circuit-breakers/radio4") ) {
|
|
setprop("/systems/electrical/outputs/transponder", bus_volts);
|
|
} else {
|
|
setprop("/systems/electrical/outputs/transponder", 0.0);
|
|
}
|
|
|
|
# DME and ADF Power
|
|
if ( getprop("/controls/circuit-breakers/radio5") ) {
|
|
setprop("/systems/electrical/outputs/dme", bus_volts);
|
|
setprop("/systems/electrical/outputs/adf", bus_volts);
|
|
} else {
|
|
setprop("/systems/electrical/outputs/dme", 0.0);
|
|
setprop("/systems/electrical/outputs/adf", 0.0);
|
|
}
|
|
|
|
# Autopilot Power
|
|
if ( getprop("/controls/circuit-breakers/autopilot") ) {
|
|
setprop("/systems/electrical/outputs/autopilot", bus_volts);
|
|
} else {
|
|
setprop("/systems/electrical/outputs/autopilot", 0.0);
|
|
}
|
|
|
|
|
|
# return cumulative load
|
|
return load;
|
|
}
|
|
|
|
##
|
|
# Initialize the electrical system
|
|
#
|
|
|
|
var system_updater = ElectricalSystemUpdater.new();
|
|
|
|
# checking if battery should be automatically recharged
|
|
if (!getprop("/systems/electrical/save-battery-charge")) {
|
|
battery.reset_to_full_charge();
|
|
};
|
|
|
|
system_updater.enable();
|
|
|
|
print("Electrical system initialized");
|
|
|