I created a function that runs too slow! Can you help me?

[LuisEngineer]

Hi everyone!

I just created a FUNCTION to find the column number of a cell in other BOOK depending of two variables. For 100 cells it takes 3 minutes to calculate!

THIS IS MY CODE:

     
Option Explicit


Function ENCUENTRASEM(takt As Double, wagon As String) As Double

Dim col As Integer
Dim row As Integer
Dim res As Integer

Dim NumRows As Integer
Dim NumCols As Integer
NumRows = 370
NumCols = 148

res = -1
For row = 8 To NumRows
    For col = 5 To NumCols
    
        If Application.Workbooks("SHM_170720_0300_TSH_CHU_Takt-Schedule_V049").Worksheets("3.TAKT SCHEDULE").Cells(row, col).Value = wagon And Application.Workbooks("SHM_170720_0300_TSH_CHU_Takt-Schedule_V049").Worksheets("3.TAKT SCHEDULE").Cells(row, 1).Value = takt Then
            res = col
            Exit For
        End If
        
    Next col
    
        If res <> -1 Then
            Exit For
        End If
Next row

ENCUENTRASEM = res

End Function