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Venus GX - Modbus TCP - incorrect values for "User yield"?


I am connecting via Modbus TCP to a local Venus GX.
Everything works fine except for the readout value of Register 790 - "User Yield"

The "Victron Connect" app shows the CORRECT values and the readout works as expected
BUT the
2nd MPPT charger connected to VE.Direct 2 port. show different value.

According to the "CCGX-Modbus-TCP-register-list.xlsx"

Unit ID /DeviceInstance Remark
245 258 CCGX VE.Direct 2 port, Venus GX VE.Direct 1 port (ttyO2)
243 260 Venus GX VE.Direct 2 port (ttyO4)

I compared the readout via QMod Master and here are the results .
the first charger shows the correct value via Modbus:


The 2nd one shows different values:


According to the register list:

Address Type Scalefactor Range
790 uint16
10 0 to 6533.6

The readout value is at least 1 digit to short!
The value should have been ~ 72670 or so

This is not critical
but I was wondering if this is just a "small bug" in the
ModBus TCP mapping on the "Venus GX" ?

As far as I can tell, all the other values seem to give the correct values!

Can anyone confirm this behavior or am I wrong here?

Best regards

juergen pflug asked

0 Answers

Multiplus-II loud humming without load, Error 8/11 when set to charger/inverter mode - dead ?

this is kind of a simplified question of my previous post, after some investigations.

I have a 3-phase ESS with 3x Multiplus-II 5kVA, no loads connected, external control, pylontech battery set.I use it to store excess solar produe and do grid assist. Main grid is always connected and able to provide 20kVA total (3 phases). I use an ET-340 to measure net grid in/outflow and command the ESS via Modbus/TCP as needed.

Very simple installation - connected to my internal grid for grid assist only on AC-In. to say that again, nothing connected to AC out.

The system only worked for a few days (less than 30 days definitely). Now it is dead.
Here is the sequence of events:
- overload error on one inverter (L1) (how can that happen, with connected grid)
few days later,
- "BMS Internal Error Alarm: Alarm" (and batteries dont charge any more)
persistent, followed by
- Low Battery Alarm (no wonder, batteries are eventually depleted)
followed by
- VE.Bus Error: VE.Bus Error 8: Ground relay test failed

and since, the system is in error state, and not working.
Batteries eventually switched off, unpowering their hub (as it is run from the 48V), so now, no battery pack any more (but that can be seen as normal and to be solved separately)

When set to "on", the Multiplusses try to connect to the Grid, but give up immediately and show a blink code (one different than the two others) which is not explained in the victron app.

I assume that one or two of the Multiplus-II 5kVA devices are broken, but as my provider wants to be paid to check them i rather ask community here for your opinion :)

.. if i set the multiplus-II switch to "I" (charge only), they engage with the grid (you can hear the relay) but then one hums very loud and agressively.
.. if i set the multiplus-II switch to "II", they try to engage with the grid but switch off more or less immediately, i assume with that error 8, and they disturb the grid enough to kick the SMA inverter connected before them off the grid.

Here are 3 short video clips (sorry for the moving camera in video 2, i tried to capture the sound/humming better).

Video 1: Behavior when starting up as charger only: (waiting form mains, should be ok)
Video 2: Behavior/humming when connected as charger: (only #1 is humming)
Video 3: Behavior when having tried to connect in switch setting "On"

Anyone able to diagnose this ?

Thanks for your assistance


jacola asked
dgnevans commented ·

2 Answers

ESS Modbus TCP AcPowerSetpoint, why is needed to be written every 60 seconds?

Currently, I have a Multi, Venus and BMV, I am controlling the ACpowersetpoint with Modbus TCP. I am working with ESS mode 2. Is it necessary to write the power set point every minute? why?

diego quintero asked

0 Answers

Multiplus - modbus - grid tie solar 3ph - use spare energy

Hi, I have a house with a 4kW GT system on FIT on phase A

I have added a 12kW array which I am planning to split over phase B and C.

I want to use a multiplus II as a smart inverter/charger from a lithium battery to store excess energy from any phase.

My supplier meter is net metering (non smart). So what I (think I) need is my own net metering meter which talks to the Multiplus and tells it to charge or discharge the battery to keep the import/export at zero. However this will only be pulling off one phase. This is why I need the external meter. If I am exporting 1kW on phase B and C (for example), with no import, but the Multiplus is on phase A, it can still import 2kW on phase A with no supplier charges.

I have researched Modbus meters but I just wondered if anyone had done anything similar - presumably I need an interface between the Modbus and the Multiplus to convert Net Export Power into Victron charge now Power.

I will have a zappi car charger and a DHW store system to soak up the excess energy. Ideally this would be priority order

1. Car (if present)

2. House batt

3. DHW cylinder

4. Export.

Although I would be willing to always do House first if that is less complicated (the zappi and DHW system will communicate internally but I don't know if they would communicate with the Victron).

I believe delays can be programmed such that the Victron could have a shorter delay on start up than the Zappi which would ensure the house batt gets priority over the car.

Of course as the car isn't always there I thought that would be best if the car got first dibs as hopefully if its a sunny day the house would get a chance later after the car leaves.

I should be good for producing approaching 16000kWh per year with this system (the 1year old original 4kW array made close to 4000 in a year and the 12kW array is less shaded)

My background is Marine - off grid so use a lot of Victron products. I have used R pi a bit so I guess this or Arduino could maybe be a useful interface if there isn't a premade solution available.

Thanks in advance


olly12383 asked
Catraz commented ·

2 Answers

ET340 via Modbus/TCP ?

Hello, i am new to Victron and want to set up a larger battery system 3 phase etc.
ET340 is already installed, but it is far away from the battery location, unsuitable to run long 485 connections.

Is there a way, has someone experience, to convince the GX controller to use Modbus/TCP to talk with the ET340 (via a modbus/TCP to RTU bridge of course),

Has anyone experience in or tried to bridge Modbus/RTU over IP (wifi, ethernet etc) ?


jacola asked
DayAndNight answered ·

1 Answer

Venus GX Modbus TCP forwarding Solaredge PV production?

Hi !

I'm using openWB to charge my EV. Unfortunately the Solaredge PV inverter allows only one concurrent TCP connection.

That means if the GX device is talking to the Solaredge the communication to the openWB is blocked.

But I've seen in the Modbus TCP menu of the (Venus-)GX that there is an entry for the SE PV inverter. I checked so far the documentation of the GX but without success.

Can anybody explain me what this means? May be I can use it to retrieve the production of the SE via the GX device.


Thanks !


deichel asked
deichel edited ·

2 Answers

multiple solaredge inverters with multiplus 2

Good Morning,

I have a system with 1 Solarege 3,5kW and Multiplus 2 with battery. All works well together. I read the solaredge PV data into the Victron VRM (Solaredge Register 811) with TCP Modbus like explained by Victron.

But now I want to install a second Solaredge Inverter (3 Phase). How can I get the second PV production value into my Victron sytem, either the sum of both, or each one?

Victron installation manual only offers to read out the device ID 126. Is it possible to add addtional pv production systems? I think this option will be interesting for many people.

thank you.


gnagflow asked
gabe answered ·

2 Answers

Can I use the command "Input Power 1" for apparent power AND active power?

Hello Victron users and experts,

I hope you have some experiences in using Modbus-TCP commands. Perhaps my question is very simple to you. I found command "Input power 1" in the Modbus-TCP Register list and have to know something about the dbus-unit "VA or Watts". Do you know if I can request both types of power (apparent / active) ?

Thank you for your answer, because I'm not sure.

Manuel M. asked

0 Answers

Venus GX - GPS Speed Units


I have changed the units used for GPS speed to mph from m/s using Remote Console. It still shows as m/s when viewing from the VRM dashboard and the ModbusTCP states that the units are m/s in the spreadsheet. Does this unit change not transmit through to VRM and ModbusTCP?

Rob Howdle asked
Rob Howdle answered ·

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

0 Answers

Multiplus II and Fronius Symo 10.3 - Modbus Questions.

I am designing a 10 kW PV no break supply system including 3 x MP II's (ESS AC PV on ACout 1), whereby I will have extra PV available at times. I have the availability to thermally bank any excess, when certain conditions are met, through my home automation system.

I have looked at the MODBUS map but cannot determine which of the fields will give me total PV output from the Fronius.

Any help on which fields I require to initiate a control command when PV output is greater than total load requirements, would be greatly appreciated.

Dee Ess asked
Dee Ess answered ·

3 Answers

Venus GX and Modbus

Hi all,

I'm trying to use Venus GX to communicate with my Siemens PLC. At Venus GX I am using VE. Direct 1 and VE. Direct 2. At Siemens' TIA PORTAL, we established the Data type, Start Address and UNIT. However, I couldn't establish the connection. So I used a Modbus Scanner to see if I was really getting the information from Venus yet I can't access any modbus messages from the device. I used the data as Holding Register, I have already activated the Modbus function of the device and I don't know what is missing.

Thank you in advance

FFGG asked
cchiappes commented ·

1 Answer

Venus Modbus System Values and Control

Hi i have carried out a number installations using the Venus unit combined with Multiplus, Smart solar and BMV units. We poll the Venus unit with no problems for all data from the three Victron units with no problem. It is the Venus system value registers that seem to be hit and miss.

Unit ID 100 with registers ranging from 800-866

The attached screen shot shows all system values as 0 and the control for relay 1 does not operate, and yet on other occassions and values will be populated and the relay (address 806) has worked.

Within the Venus conus config i have tried automatic, BMV and Multiplus for Battey monitoring undet the system setup, but none of them make a difference.

Currently running the latest firmware v2.51

Has any body else experianced this? And how did you fix it?


s18mat asked

0 Answers

Janitza UMG604E connected by modbus to 6 Quattro48/8000 for self-consumption system


This is the setup I am thinking of for a costumer running several PV plants. We want to add batteries for pure self consumption and charge only when PV is feeding to the grid. For that reason we want to get the current of every line from a already existing Janitza UMG 604 E via modbus TCP. Is this working? Where to read about the setup? Thanks in advance! Answers in German also welcome

Marco Steurer asked

0 Answers

MPPT to Venus GX Using USB

Hi, have just connected an MPPT to a Venus GX, using USB, to then read across ModbusTCP, but the device instance reports as 288 (258 if connected to VE.Direct 1). This instance isn't referenced in the Modbus mapping table. Can it still be read using Modbus? It shows up fine in VRM.



Rob Howdle asked
Rob Howdle answered ·

1 Answer

modbus TCP & multiplus-ii GX

I want to take control of my multiplus-ii GX in ESS mode 3

The usage is througth the MOdbus TCP protocol on LAN

Does LAN refer to Ethernet input, Wifi input or both

michelP asked
Jonatanjensen answered ·

1 Answer

EM24 via Modbus - understanding the energy values

I started to use Modbus to read some data from EM24 and am little bit confused about the numbers. Maybe someone can help me to interpret them.

When looking at the display of EM24 or alternatively on CCGX a see an "AC total" of 3775.8 kWh. In which modbus register can I find this value ?

I'm asking because when I read the modbus registers 2622 through 2626 ('Energy from net' for L1,L2,L3) I get a total of 6832 kWh. The total of 'Energy to net' is 6646 kWh

Pirx asked
Pirx edited ·

0 Answers

Start generator via ModBusTCP on Quattro


Is it possible to start/stop the generator on a Quattro using ModbusTCP? It looks like this is register 3223 from the spreadsheet (CCGX-Modbus-TCP-register-list-2.23.xlsx) , but I have no idea which id this corresponds to and they all fail. It is listed as com.victronenergy.genset in the dbus-service-name.

I am using ModbusTcpClient on a local Raspberry Pi to do this from Python.



miketuk asked
uniport commented ·

2 Answers

Connect Venus GX to PRTG(Paessler AG)

Hello all,

Is there a way to connect my Venus GX to my PRTG using MIB? Or any other way?

samatcomm asked
mvader (Victron Energy) answered ·

1 Answer

Control the Venus GX controller true Modbus tcp/ip with commands like charge/discharge


We are working on a project to charge/discharge a battery by using a PLC. We have seen that the Venus GX supports Modbus tcp/ip but it is not clear to us whether it is possible to control the controller via this protocol. Here we think of for example:

- Charging the battery

- Discharging the battery

- Charging speed of the battery

- Battery Discharge Rate

So we want to get the intelligence out of the controller and control it from the PLC. Is this possible?

Thanks in advance for your efforts!

Student_Remko asked
AnaF answered ·

4 Answers

How to view Color Controller data on VRM portal and also collect data on an external device via modbus?

Is it possible to view inverter data on vrm portal and also have the color controller send data to another external device via modbus. The color controller only seems to have one ethernet port. If I use this ethernet port to send data to the external device, is there a way to also view this data on vrm portal (say via wifi or some other way?)

Bhagyashree Shelke asked
Rob Howdle answered ·

1 Answer

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
Guy Stewart (Victron Community Manager) answered ·

1 Answer

Modbus TCP unit ID Multiplus II GX

What is the Modbus TCP unit ID for the Multiplus II GX ?



MBM asked
osaether edited ·

1 Answer

MPPT with modbus


I got a MPPT 150/85 MC4 hooked up, and I want to get data from it with modbus TCP.
My modbus connection works, as I can get other data, like register 840 etc,
but nothing from the PV system.

I tried registers:
- pv voltage (776)
- yield today (784)

But empty response. Am i missing something?

betz asked
Rob Howdle answered ·

2 Answers

Fronius Galvo 2.5-1 and Multi 5.0 problems with zero feed in and frequency shift

Hello I have a multiplus 5.0/Venus/Fronius Galvo Grid-connected solar backup system. It Is connected to the local grid and must not feed power back to the grid.

I have set up both systems as described in literature (modbus, ip settings, etc) and added the self consumption hub assistant. The fronius appears in the venus menu and everything seems fine at first.

however, sometimes the fronius is temporarily pushing power onto the grid (up to 1000W for up to 10 seconds) and then resetting itself. This happens when the daytime loads are small and the battery backup is 100%. The fronius will turn on, push power to grid and reset again and again. This also seems to be overcharging the batteries. The whole control system seems very sluggish.

I dont understand why the fronius seems slow to respond to frequency shifting. I feel like I am not using the right assistant for this application. I have read everything about fronius and victron on this website a bunch but just cant get the system to respond right in all situations.

I want to understand better the control mechanism. It seems that while the grid is available the victron multi and venus should be controlling the fronius via modbus, and when the local grid goes down it should switch to frequency control. Am I right? Why cant the venus just control via modbus the whole time? Which assistant would this use?

Alternatively, can I just use a fronius smart meter and separate the two systems? Anyone have experience with this?

Thanks for the any help.


etarkleson asked
etarkleson answered ·

5 Answers

Best pratice deployment with Venus Gx, bnv702 and multiple mppt charge controller

It seems that there are a few topics that covers multiple mppt etc.

I Just Wonder, Whats the best pratice setup if you have

Venus Gx

2 Smart solar mppt 100/35




Im particulary conserned about :

-making the charge controllers play well i sync

-Utilize common voltage and temp sence from the bmv702

Is there available any illustrations, White papers etc.


Jgy67 asked
NET4Gpve answered ·

2 Answers

Getting WattHours from grid meter


Currently I can only see KwH from the grid meter (one of the ET112's). Even though uint32 counters are used, I can still only see 1/10th of a KwH. This document that I have says that the scale should be 100 (the modbus register sheet, version 2.20) - how can I enable this or get a wH value ?

Thanks !

dewitpj asked
dewitpj commented ·

1 Answer

How to cut off current generated by inverters in mode 3

Hi everybody,

We are considering the possibility of installing 3 units of Multiplus II 48/3000/35-32 with one battery in a tertiary building in Spain.

The idea woud be that these 3 Multiplus II, would act as reversible chargers / inverters working in mode 3 and, thus, following the power setpoints established by an external control loop through Modbus TCP. This is for R&D purposes and we only want to make a pilot proving that it is feasible to store electrical energy during night (low kWh price) and use it inside the building during day (high kWh price). Economical profitability is not the focus in this pilot.

AC-IN terminals of the Multiplus II units would be connected to the bars of the main switchboard in the building by means of a 4-pole contactor (among other switchgear). See diagram:


AC-OUT terminals will be idle, that is, although you can see some wiring and switchgear in the diagram to enable future connection of critical loads, this only would happen prior to reconfiguration of ESS to mode 1 (Keep batteries charged) for the multis to act as a UPS. Again, for the purpose of my question, no critical loads will be connected, AC-OUT terminals will be idle, and configuration will be in mode 3 (external control).

Contactor -K1 in the diagram will be governed by an INDEPENDENT system which will monitor energy going through a grid meter and will open the contactor whenever the power generated by inverters is being fed back to the public grid.

The thing is that I don't know how to size contactor -K1 in the diagram. I can see that sizing should take into account two cases:

a) When charging battery, I can assume that current will not exceed 32 A in any case, according to the Multiplus II datasheet.

b) When inverting, I assume that the maximum current through the contactor will be 3000VA/230V= 13 A. But my concern is that here the inverters are working as a CURRENT SOURCE rather that as a voltage source because they are following the Modbus TCP power setpoint.

Therefore, my questions are:

1. Could it be the case that the inverters "push harder" when they see contactor's opening? Would it be enough to put a contactor with rated current of 32 A (Utilization catetory AC-1) to account for case (a) or should I put a contactor with higher rated current (or harder utilization category) to account for case (b)?

2. How long will it take for inverters to realize that they cannot fulfill the power setpoint in the Modbus TCP map and stop trying?

3. Can this situation be harmful for the inverters?

4. In the end, which will be the error status of inverters? Will I be able to rearm them through Modbus TCP or only on-site?

Thank you very much in advance (and sorry for the length of the question).

Angel asked
Boekel commented ·

2 Answers

Maximum data rate for Mode 3 external control


When using the Modbus external control capability of the inverters I have noticed that when the control data is sent more than twice per second, the response of the inverters rather than being faster they are much slower with some times not even responding.

I guess this could also be somehow related to the ramping restrictions on the inverters, but is there any data rate limitation when using an external setpoint over Modbus that we should be aware of?


egs.ust asked
Markus edited ·

1 Answer

Assistance needed regarding writable registers of CCGX


i have a configuration of 3 one phase 3KVA Quatro Victron inverter/cahrger that are connected with one Colour Control GX interface. Following the registry map (CCGX-Modbus-TCP-register-list-2.12.xlsx) I managed to communicate with CCGX via ModbusTCP and to collect all the measured values. In the register list there are also some writable parameters like "flags" and "switch position". I am able to control register 33 (switch position) through writing 1,2,3 or 4 in the register, but writing to the other writable registries (like 22,38,39) is ineffective. Is there any restriction through the configuration of Victron that doesn't allow writing to these registers?

Laz asked
Angie commented ·

2 Answers


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