'Sub relay_control()

'It is presumed that QuickField is already started, the problem coil.pbm is opened.
'The plunger is placed in x=0 position
'LabelMover file relay.qva is opened


if (MsgBox("1. Start QuickField and open coil_problem.pbm" & chr(13) & "2. Open relay_control.qva in LabelMover." & chr(13) & "3. Press OK button.",1) <> 1 ) then
WScript.Quit() 
end if

'relay parameters
Dim x_out			' As Double
Dim x_in			' As Double
Dim m_mass		' As Double
Dim k			' As Double
Dim x_spring_free 		' As Double

x_out = 0.01        		' pull out position. m
x_in = 0.006        		' pull in position, m
m_mass = 0.0045     	' plunger weight, kg
k = 4.0               		' spring constant, N/m
x_spring_free = 0.015     	' spring free would be position, m


'initial conditions
Dim t_time 		' As Double
Dim x_position 	 	' As Double
Dim v_speed 		' As Double

t_time = 0.0    		' time, s
x_position = x_out  		' plunger position, m
v_speed = 0.0         		' plunger speed, m/s

'integration time step, s
Dim dt_time_step		' As Double
dt_time_step = 0.005



Dim theForce		' As Double
Dim max_time		' As Double
max_time = 0.2        		' maximal integration time


While (t_time < max_time) And (x_position > x_in)
' electromagnetic force
    theForce = getQfForceX(x_position)
' add spring force
    theForce = theForce + (x_spring_free - x_position) * k
' calculate acceleration and speed
    v_speed = v_speed + theForce / m_mass * dt_time_step
' calculate plunger position
    x_position = x_position + v_speed * dt_time_step
    t_time = t_time + dt_time_step

''''''''''''''
'output results are stored in LabelMover
''''''''''''''
Wend

'End Sub


Function getQfForceX(x_position)
'calculate force in QuickField
'It is presumed that QuickField is already started, the problem is opened.
'The plunger is placed in x=0 position
'LabelMover file relay.qva is opened


' 0. hook LabelMover (QuickField tool)
' 1. specify plunger position
' 2. get the force
Dim qlm			' As qlm.SimpleInterface
Set qlm = CreateObject("qlm.SimpleInterface")

' 1. specify plunger position
Call qlm.SetVariation (0, x_position)
' 2. get the force
Call qlm.Solve
getQfForceX = qlm.GetResult(0)
' each step is stored in LabelMover
End Function