from win32com.client import Dispatch

R3 = Dispatch("SAP.Functions")
R3.Conn.System = 'xxx'
R3.Conn.Client = '100'
# other values needed to pass to R3.Conn
R3.Conn.logon #here is the problem

from win32com.client import Dispatch

Functions = Dispatch("SAP.Functions")

Functions.Connection.Client = "000"
Functions.Connection.ApplicationServer = "your server"
Functions.Connection.Language = "EN"
Functions.Connection.User = "you"
Functions.Connection.Password = "your pass"
Functions.Connection.SystemNumber = "00"
Functions.Connection.UseSAPLogonIni = False

if (Functions.Connection.Logon (0,True) == True):
    print("Logon OK")
    RfcCallTransaction = Functions.Add("RFC_READ_TABLE")
    strExport1 = RfcCallTransaction.exports("QUERY_TABLE")
    strExport2 = RfcCallTransaction.exports("DELIMITER")
    strExport3 = RfcCallTransaction.exports("ROWSKIPS")
    strExport4 = RfcCallTransaction.exports("ROWCOUNT")
    tblOptions = RfcCallTransaction.Tables("OPTIONS")
    #RETURNED DATA
    tblData = RfcCallTransaction.Tables("DATA")
    tblFields = RfcCallTransaction.Tables("FIELDS")


    strExport1.Value = 'AGR_DEFINE'
    strExport2.Value = ";"
    strExport3.Value = 0
    strExport4.Value = 10

    if RfcCallTransaction.Call == True:
        print ("Function call successful")
        #print (tblData.RowCount)
        j = 1
        while j < tblData.RowCount:
            print (tblData(j,"WA"))
            j = j + 1