Datamanager Clock Time

Hi All,

I’ve notice [ again ] that the ‘clock’ on the Datamanager Card in my Fronius Symo has drifted quite a lot. I was wondering if anyone else is / has experienced the same problem. It causes a particular problem when querying /solar_api/v1/GetArchiveData.cgi via the Fronius API

Circuit Board Version 2.4D
F/W 3.14.1-10

I used the Fronius inverter GUI to DISABLE and then [re]ENABLE the automatic time setting feature to reset the clock.

Status Code: 7
UAC: 237.6V
Inverter Time: 2019-12-03T08:29:57+08:00
Local Time: 2019-12-03T08:30:03+08:00
Delta Time: 6 Seconds
Inverter Temperature: C:

Status Code: 7
UAC: 237.8V
Inverter Time: 2019-12-03T08:35:03+08:00
Local Time: 2019-12-03T08:35:05+08:00
Delta Time: 2 Seconds
Inverter Temperature: 51C:

Status Code: 7
UAC: 237.6V
Inverter Time: 2019-12-03T08:40:06+08:00
Local Time: 2019-12-03T08:40:09+08:00
Delta Time: 3 Seconds
Inverter Temperature: 52C:

i have never paid attention… maybe this is why sometimes people have that missing recording every now and again

well it might be because the data manger clock when set to auto update, only changes the time when it gets to 3 or 4 seconds out, this time drift may be caused by the inverter line voltage and frequency changing at different times of the day ??? and it may only auto time at midnight as well


Yes. An incorrect clock time will effect retrieving data from the Fronius log file as opposed to the realtime data.

Jim - How would the clock know that it was 3 - 4 seconds out? I assume that the Datamanager card polls an NTP server somewhere on the Internet at a periodic interval. It’s possible that that they rely on grid frequency but they would have to cater for 50Hz or 60Hz. Possibly Fronius themselves mainitain that server. I could try a packet trace but may need to collect a lot of data to find any UDP 123 traffic.

Incidentally the time displayed on the inverter itself does NOT seem to reflect the time on the Datamanager card. They can be set independently!

Over the last 24 hours it has been 3-4 seconds out.

well i have a windows computer here with the same time drift problem it would make during the summer 2 min a day some days, i installed a second clock to keep better time, this checks the time every hour, BUT i have noticed it only changes the computer clock if there is more then 4 sec time difference.
on days when the solar output was low and the grid voltage stayed bellow 250 volts the old computer clock was spot on,just seemed to happen when high grid voltage was happening or on days when output and volts were swinging up and down- ie sunny then clouds back to sunny again. so i think the 4 sec out might be the allowable limit to save band with on the time keeping server fronius use. Jim

I hadn’t thought about it, so I just checked my Primo 6.
The datamanager clock is synchronised to within a second with ‘true’ time, despite not having been touched since it was turned on 1.5 years go.
I have it set to turn off overnight, and it fires back up when the sun provides enough power on the panels each morning.
I’m fairly confident It must be synchronising with an external time source somehow, possibly using NTP or SNTP to do this, but theres no setting or config to indicate this, or to tell it which NTP servers to use.

There is a “Set time automatically” checkbox and a “Time zone” field under Settings/General on the inverter web pages. Clearly it would use NTP like everything else in the modern world.


I would have thought that both the Primo and the Symo, which I have, both use the same method of setting the time; The in-built DataManager card. What the card uses to get / set the time is another question.

Perhaps - everything else in the modern world that uses NTP has a field to specify which NTP server to use, so it can be changed to use a local server. Using NTP to chime from Australia and every other country to a reference server in Austria makes little sense. In other devices ‘set time automatically’ means ‘query the browser and set the time to the time of the device running the browser this is visible in’ as a one-time-thing

I’ve been logging the time difference between the REAL time ( ntp ) and the inverter time using my Raspberry Pi. The horizontal axis of the graph is local time ( WST ). The difference so far is always +VE meaning that the inverter is lagging behind the real time. There is no doubt that there is some ‘JSON overhead’ in extracting the time so I would expect some delay.

I thought that I would provide an update to my earlier post. The internal clock on my Fronius inverter appears to be drifting further from my ntp disciplined Raspberry Pi over time.

In fact if I plot the average daily DELTA the picture becomes much clearer.