2 Replies Latest reply on Oct 20, 2015 7:19 AM by scotc

# Is there a way to use a logarithmic function to transform a results of UnDP?

Hi all - I have some devices where I am trying to monitor the optical light levels of the optics.  The UnDP returns results that are expressed in mW and I would love to display them as dBm.  I don't see a function for that in the transform results tool so I am trying:

formula = log({custom_poller_rxPower}/10000)*10 takes a returned value of 6285 and transforms to 6.285, acting like the log function isn't working.  I have validated the formula using Excel and it appears to work fine: LOG(6285/10000)*10 = -2.02.

Is this just a Solarwinds limitation?

Thanks,

Scot

• ###### Re: Is there a way to use a logarithmic function to transform a results of UnDP?

You may be able to use the taylor series expansion to approximate the dBm but the formula would look ridiculously complicated.  Unless you absolutely have to have the information stored in the database as dBm, I would use SQL to do the conversion on the front end.  Use the Report Writer app to pull the data with a query and display that info on a summary page using a report resource.  You can then use that same query, slightly modified, to create an alert for high dBm.  If you have other metrics you need, those can be combined into the query later on too.  So you can poll SNR and be able to calculate the noise floor then display all those things in one nifty table.

Matthew Hawks

Loop1 Systems

• ###### Re: Is there a way to use a logarithmic function to transform a results of UnDP?

Thanks Matthew.

I opened a case with TAC and they verified that LOG is not a function that is implemented.  I asked for a feature add and in the meantime, I am going to take the easier route of just alerting off of the mW levels. I am also saving the data so that historical charts are used and we can at least see when a change occurred.  It may not be the prettiest, but it will get the minimum job of alerting on low light levels accomplished.