Unix time-based time stamps on PV array data

Calahonda52

I have this over in the RE section but said I will ask here as well.

PV array has Unix time-based time stamps on it

The time interval seems close to, but not exactly a minute so I wonder how to deal with that problem.

The excel sheet, attached, shows an overrun of 3 seconds in a 4 hour 1 minute period, math at Cell A241 I 241

I tried hh:mm but it truncates rather than round.

unknownlegend

Your excel formula is fine. I wouldn`t attempt rounding / correcting the human readable time you've translated to in excel.

It looks like a problem with the logging on the device itself. It may be attempting to write out on a 1 minute interval but due to processing lag (or whatever), it isn`t getting the interval perfect. I see it seems to start out with a big deviation, and normalizes towards 1 minute. May be that it sorts out ancillary processes on boot and then has more capacity for regular logging. Curious problem.

DublinDilbert

Does the system generating the data have a proper real time clock? They could have implemented the real time clock in software, so you would see that type of drift.

Calahonda52

DublinDilbert wrote: »

Does the system generating the data have a proper real time clock? They could have implemented the real time clock in software, so you would see that type of drift.

I don't know!
Its an 11kW array made up of 295 max power W panels, each with its own micro- inverter.

the excel tab says sungate and the name on the web browser is Letrika.

When the system was spec'ed, little or no attention was given to the back end so to speak. My guess is that the back end spend was cut back to max the number of panels in the Cap-Ex, a bit like leaving out the silencers in a MHRV system when budget becomes an issue