%It is presumed that QuickField is already started, the problem coil.pbm is opened.

pkg load windows %load windows package to enable COM

%relay parameters
x_out = 0.010;       %pull out position. m
x_in = 0.006;        %pull in position, m
m_mass = 0.0045;     %plunger weight, kg
k = 4;               %spring constant, N/m
x_spring_free = 0.015;     %spring free would be position, m

%initial conditions
t_time = 0;         %time, s
x_position = x_out; %plunger position, m
v_speed = 0;        %plunger speed, m/s

%integration time step, s
dt_time_step = 0.005;
%maximal integration time, s
max_time = 0.2;

%plot initial position
plot(t_time,x_position,'-or','MarkerSize',2);
%add axis labels and title to the plot
xlabel('Time t, sec.');
ylabel('Position x, m');
title('Plunger position vs. time');
hold all


while (t_time<max_time) & (x_position>x_in)

    theForce = getQfForceX(x_position); %electromagnetic force    

    theForce += (x_spring_free - x_position)*k; %add spring force    

    v_speed += theForce/m_mass * dt_time_step; %calculate acceleration and speed

    x_position += v_speed * dt_time_step; %calculate plunger position

    t_time += dt_time_step;
    
%plot x-position
    plot(t_time,x_position,'-or','MarkerSize',2);
    hold all
end