question

mrrose83 avatar image
mrrose83 asked

Modbus stopt sometimes

I see that since the last update the cerbo stops sometimes the Modbus PV Inverter connection. It takes about 5min to reconnect the Website.


Somebody else monitors these?

Modbus TCP
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3 Answers
pvpax avatar image
pvpax answered ·

In my case the modbus connection does not come back until the next morning or I restart the inverter or at least its modbus tcp server. It usually happens at noon or in the early afternoon.

openWB also loses connection. It never did until I've set up Venus OS.


SMA STP 8.0 on latest firmware

Raspberry Pi with Venus OS large 2.09~14 (same behaviour with 2.87 standart build)

https://github.com/mitchese/shm-et340 installed and running

Multiplus II not yet connected.


openWB polls the pv inverter every 10 seconds, polling the data from Venus works but doesn't prevent the crashes either.

Venus OS seems to poll every single second. I guess this either is too often for the STP or maybe the connections are not closed correctly and lead to a kind of overflow.

Also strange: the inverter is listed twice in VRM device list but only once in remote console.


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cioringa avatar image
cioringa answered ·

I have the same problem, my Sma tripower keeps disapearing and apears only if i restart modbus server or inverter ... anyone have a fix for this ?

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bernd2 avatar image
bernd2 answered ·

I am using the open source library libmodbus from libmodbus.org to read out 8 different registers from an EasySolar-II GX with firmware 3.01 with a sampling interval of about 5 seconds. In this setup, the connection times out periodically about every 107 minutes.

However, a restart of the EasySolar-II is not needed, it is sufficient to reconnect via the

modbus_connect(...)

command. Would be interesting to find out the root cause of this...

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