Dear, and tell me how to DUDE the natural logarithm in functions, the fact is that the equipment gives the SNMP value RX number of which the formula can already calculate the logarithm
10 * LN (oid ("iso.org.dod.internet ......")) / LN (10) -40
WiKi said to use Excel spreadsheet formulas
if use LN i got error "unundefined function LN"