VBA Code: Conversion Calculator of Pressure and Temperature Using Bisection Method

VBA Code use in Userform: First make Useform:

Change name

textbox1: txtPressure

ComboBox: cmbTemperature

textbox2: lblResult

Button Name

Calculate: btnCalculate

Reset: CommandButtonReset

Quit: CommandButtonQuit

Now Right click on UseFrom to View Code:

Now Copy and Paste this below Code:

Option Explicit

Private Sub UserForm_Initialize()

    ' Populate the temperature ComboBox

    cmbTemperature.List = Array("300", "400", "450", "500", "550", "600")

End Sub

Private Sub btnCalculate_Click()

    ' Handle input validation and perform the bisection method

    

    ' Input validation for pressure

    If Trim(txtPressure.Value) = "" Then

        MsgBox "Please enter a pressure value.", vbExclamation

        Exit Sub

    ElseIf Not IsNumeric(txtPressure.Value) Then

        MsgBox "Pressure must be a numeric value.", vbExclamation

        Exit Sub

    ElseIf CDbl(txtPressure.Value) < 0.001 Or CDbl(txtPressure.Value) > 1000 Then

        MsgBox "Pressure must be between 0.001 and 1000 bar.", vbExclamation

        Exit Sub

    End If

    

    ' Get selected temperature and assign corresponding Ke value

    Dim selectedTemperature As Integer

    selectedTemperature = CInt(cmbTemperature.Value)

    

    Dim Ke As Double

    Select Case selectedTemperature

        Case 300: Ke = 0.00434

        Case 400: Ke = 0.000164

        Case 450: Ke = 0.0000451

        Case 500: Ke = 0.0000145

        Case 550: Ke = 0.00000538

        Case 600: Ke = 0.00000225

    End Select

    

    ' Perform the bisection method

    Dim low As Double, high As Double

    low = 0

    high = 0.999

    

    Dim X As Double

    Dim i As Integer

    For i = 1 To 20

        X = (low + high) / 2

        If Abs((16 * X ^ 2 * (2 - X) ^ 2) / (27 * (1 - X) ^ 4 * txtPressure.Value ^ 2) - Ke) < 0.000001 Then

            lblResult = Format(X * 100, "0.0")

            Exit Sub

        ElseIf ((16 * X ^ 2 * (2 - X) ^ 2) / (27 * (1 - X) ^ 4 * txtPressure.Value ^ 2) - Ke) > 0 Then

            high = X

        Else

            low = X

        End If

    Next i

    

    ' Display result

     lblResult = Format(X * 100, "0.0")

End Sub

Private Sub CommandButtonReset_Click()

    ' Clear the input and result controls

    txtPressure.Text = ""

    cmbTemperature.Value = ""

    lblResult = ""

End Sub

Private Sub CommandButtonQuit_Click()

    ' Close the UserForm

    Unload Me

End Sub

Now we have to create a Start button in Excel which is used to start our Conversion Calculator.

After that Press ALT+F11, Then insert a module

Copy and Paste this Code:

Sub Button1_Click()

UserForm.Show

End Sub

Now save Excel file as Excel Macro-Enabled Workbook.

Now Just Click to Click here to Start button and then Enjoy your Calculator.😏