Option Explicit

Type uab4: ab(0 To 3) As Byte: End Type
Type uab8: ab(0 To 7) As Byte: End Type

Type uFlt: f    As Single: End Type
Type uDbl: d    As Double: End Type

Function Byte2Sng(ab() As Byte) As Single
    Dim ub      As uab4
    Dim uf      As uFlt
    ub.ab(3) = ab(0)
    ub.ab(2) = ab(1)
    ub.ab(1) = ab(2)
    ub.ab(0) = ab(3)

    LSet uf = ub
    Byte2Sng = uf.f
End Function

Function Hex2Sng(ByVal s As String) As Single
   
    Const sPad  As String = "00000000"
    Dim i       As Long
    Dim ub      As uab4
    Dim ab(0 To 3) As Byte

    s = Replace(s, " ", "")
    If Len(s) > 8 Then Exit Function
    If Len(s) < 8 Then s = Right(sPad & s, 8)

    For i = 0 To 3
        ab(i) = CByte("&H" & Mid(s, 2 * i + 1, 2))
    Next i

    Hex2Sng = Byte2Sng(ab)
End Function