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Modbus TCP

Cerbo GX ESS Mode 2 Intermittent Code 2 "Connection Error"

I have a Multiplus-II, SmartSolar MPPT, with a Cerbo GX for the brains. I've written an ESS mode 2 control program that runs on a dedicated Raspberry Pi. The program queries the Cerbo on a one-minute cycle using Modbus TCP, sleeping between queries, and gets an intermittent code 2 (Connection Error) communicating with the Cerbo several times over the course of a 24-hour day.

The error has shown up at all times of day and generally lasts for 10 minutes or less. I know the Raspberry Pi is still online because that's how I access it during the error. I know the Cerbo is still online because I can see it on the router. I suspect the Cerbo is not locked up or rebooting because it still feeds data to the VRM portal while the code 2 is going on. My program has code to retry querying the Cerbo up to four times over the course of 12.5 minutes -- all the retry loop does is reissue the "read register" request, it doesn't close or open the connection.

Any ideas? All firmware is current as of this date.

jm0278 asked
lifeingalicia answered ·

2 Answers

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?

mrrose83 asked
pvpax answered ·

1 Answer

Betriebszustand über Modbus auslesen

Moin in die Community,

ich bin neue in der Victron Welt.

Ich kommuniziere über einer Beckhoff-Steuerung via Modbus mit einem Cerbo CX. Ich habe mit drei MultiPlus II eine Drei-Phasen Netz aufgebaut.

Ich würden gern über Modbus auslesen ob sich die MultiPlus II im charger oder inverter Mode befinden. Ich habe in der Excel Tabelle nix dazu gefunden.

Hat vielleicht einer von euch eine Idee wie ich das erfassen könnte?

akoch asked
wengelhart commented ·

2 Answers

Use the "feedin excess solarcharger power" button with modbus?

I will find it clever to be able to switch the "feedin excess solarcharger power" button through modbus TCP to manage network injection from home automation.
Of course this will mean integrating it into the excel modbus table.
Is it possible to consider it?
Thank you in advance.



philoup asked
elvis answered ·

1 Answer

TCP Mod Bus Adresse for Critical Loads

Hallo ich suche nach der Mod Bus Adresse für die Critical Loads meines Multiplus II an einem Cerbo GX. Das MODbus TCP Register hab ich schon druchsucht leider ohne ergebnisse. Die ID für den Multiplus ist hoffentlich die 227? Oder?

Danke schon mal für euere Hilfe.

weisnet asked
weisnet answered ·

4 Answers

DVCC charge current limit - Compensating for DC loads

I have an off-grid system with a 24v 90Ah battery bank, a 1600VA multi plus, 2 100/50 MPPTs, a BMV, a CCGX and a large DC load (up to 90A). I want to limit the charge current to 45A. In the CCGX manual the DVCC section states that the DVCC current limit doesn't account for DC loads. I was wondering if there is any work around for this. The system will also have a PLC with capabilities to communicate using Modbus TCP and I open to implementing a custom control algorithm on the PLC if needed.

Will Clarke asked
mi-roberth answered ·

2 Answers

Comment connaitre la quantité d'energie (Kwh) transitant par les batteries ?


Dans la cadre d'une utilisation domotique, je récupère un certain nombres d'informations sur Home assistant via Modbus. Je souhaiterai récupérer les quantités d'énergie stockées et déstockées bar les batteries (en kWh, en Wh, ..., je connais déjà les puissances "instantanées" de charge et décharge en W)). Ces informations sont à priori disponibles mais pas avec le Bus-can.

Pouvez vous me confirmer, comme je l'ai lu sur le forum anglais, qu'il est possible d'installer un SmartShunt de le connecter en, de récupérer les informations sur les flux d’énergie mais de ne pas l'utiliser comme BMS ?

Existe-il un autre moyen d'accéder à ces informations ?

Ma configuration

  • Multiplus II 5000
  • Cerbo gx
  • Batteries pylontech


grichka asked
s3b answered ·

2 Answers

Enabling Modbus TCP in Cerbo GX triggers error due to access of address 40000

This has been asked before here, but there has been no real answer unfortunately so I am trying again.

I would like to use the Modbus TCP interface to read out and monitor various values of the system, which consists of:

  • 2x MultiPlus II 5000
  • Cerbo GX (firmware version 2.84)
  • 2x Freedom Won batteries
  • Fronius Primo 8.2

As soon as I enable the Modbus TCP service, there seems to be a device making a query for address 40000, which doesn't exist:


This request seems to happen about once per minute. Not sure which device has unit ID 126, but the IP address is the address of the Cerbo GX.

How can I turn off those invalid queries resulting in that error?

Thank you.

marcus-spranger asked
marcus-spranger commented ·

1 Answer

Virtuellen Schalter mit Modbus TCP ansteuern

In der Remote Konsole kann man unter Wechsekrichter/Umschalten folgende Einstellungen vornehmen: Aus, nur Ladegerät, nur Wechselrichter und Ein.

Ich möchte nun per Modbus TCP (via Loxone) zwischen nur Wechselrichter und Ein umschalten.

Der Grund ist das ewige hin und her zwischen Netzbezug und Lieferung bei Ein, welches bei einem gewissen Ladezustand nicht notwendig ist.

Meine Frage: gehe ich richtig in der Annahme, dass dies mit Register 3126 in "com.victronenergy.inverter" möglich ist.

Wenn ja, welche Befehle sind notwendig um den Mode umzuschalten?

office asked
solarlion answered ·

1 Answer

ABB / Fimer Trio 5.8 TL OUTD communication

I just got Easysolar 2 GX and can't get it to communicate with my old ABB inverter eth board. It doesn't show up in modbus tcp devices or in PV inverters. Should I be able to do this with Modbus TCP? They are in the same network, maybe I'm missing a setting somewhere? ABB is connected to AC in.

Kari Saaranen asked
Kari Saaranen answered ·

1 Answer

Have CerboGX read PV Power via modbus from an openWB


I have a SMA Sunny Boy 5000TL-21 Inverter that does not have an interface to Victron.

Visualization is done via SolarLog200 which is also not accessible by the GX.

I also have a Wallbox (openWB) that does read the pv power from the solarlog and provides the value on modbus TCP. Problem is, the GX device doesn't recognize the Wallbox.

Is there any way to have the GX read the PV Power?

modbus documentation:

I need register #400 read by the GX.


frame77 asked

0 Answers

CCGX - DVCC -> How to Limit Charge Voltage using ModBus-TCP

I've noticed the addition in DVCC the ability to limit the managed battery charge voltage to a value of my liking. I am very happy, that this is finally possible now.
Now, I would like to set this maximum charge voltage using Home Assistant.

Inside my Modbus TCP services, I have access to
According to CCGX-Modbus-TCP Register-list.xlsx, the only writing-enabled registers are the CCGX-relay-states.

Is there any possibility set the Maximum Charge Voltage per Modbus TCP from Home Assistant? If yes, what is the register of this service?

Michael Timler asked
lsgv commented ·

2 Answers

Zero feed-in with ESS and heating resistance for leftover power - best way to control the resistance (PWM, leading/trailing edge, ...)


We've built a system with Multiplus II / Cerbo GX, Pylontech batteries and a Fronius inverter - and as the goal is zero feed-in, we added some heating resistances to heat up rooms and water for showers etc. with leftover power.

A RaspberryMatic instance is reading the live values from the Cerbo GX via Modbus/TCP (really great how easy it is to read/set values btw!) and controlling three 1 kW heating resistances via an ESP32 (Arduino-like, providing web-controllable relays). Currently, this results in possible steps of 333W, 500W, 1000W, 1500W, 2000W, 3000W.

This gives the possibility to realize almost whatever you want between the live values (pv power, ac consumption, ESS SoC, daytime, ...) and the ESP32 outputs by creating RaspberryMatic applications or scripts.

The first results are great, but - yeah the regulation steps mentioned above are quite big. It would be better to be able to regulate between 0W and 3000W without any steps :-)

So the question is: What suits best for the MultiPlus, especially with regards to micro-grid capability? I suppose that leading/trailing edge regulation isn't really good as it will have a big impact on the sine wave. Full wave control also seems like a bad idea, as it will stress the MultiPlus' regulation and/or the batteries.

The softest approach (also trying not to stress the inverters semiconductors too much) seems to be PWM with MOSFETs, which the ESP32 could also control easily at higher frequencies. But it will probably require filters to avoid EMI/disturbances in the grid, even with the resistive loads here..

Any thoughts on this are welcome!

ips-ad asked
jamierobinson answered ·

1 Answer

Cogeneration (gas generator) and ESS

Hello , experts!

There is a task to design a system in which there will be a Gas Generator, Grid and ESS.
The house has a rated load power of 138 kW. The electricity supplier (GRID) can provide no more than 80 kW. The remaining 58 kW will be added (upon load request) by the Gas Generator. They will work synchronously. The task is to install ESS between the load and Grid+Gen. The composition will include Quattro 15000 - 12 pcs. , Fronius Eco 27 - 1 pc. , Symo 15 - 2 pcs. , Cerbo GX, GX-Touch, Battery (LiFePO4) 100Ah48V - 22 pcs.
The ESS in this system should support the load during Generator warm-up, Daytime PV compensation, Start and stop Generators on event (overload power exceeding 80kW), Shutdown non-priority load in case of SOC<50%, Transmit data via MODBUS about the load on each phase, SOC.. on the Industrial controller.
During the winter, the generators will operate around the clock. Heating will be provided by them.
Do you think it is possible to implement such a system with Victron? What do I need to pay attention to? If I gave little information - I will answer. Any advice! Thank you!

kuban-invertor asked
Kevin Windrem answered ·

1 Answer

SMA Inverters Missing In Device List


First Victron Installation and straight in at the deep end.

I have 6 SMA inverters all with static IP addresses. They all show up on the Cerbo GX and give production data. On the Cerbo I can see the VRM number for each. However 2 of the inverters do not show up in device list on VRM. I can see all of them in the advanced settings however the two I cannot see on device list only have 1 widget where as the others have 2. How can I resolve this? Also anyone able to help with getting information from the Cerbo over modbus?


Many Thanks





Jack asked
daba answered ·

7 Answers

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