Cerbo GX Max amount of AC Energy Meters via RS485. VRM Dashboard Display & Data

Q&A and troubleshooting
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1

Hello Community,

I’m seeking clarity on how many RS485 meters can be connected to a Cerbo GX via a USB RS485 Modbus USB adapter, or multiple USBs if required.

I note in the Victron documentation it recommends to use separate USB adapters for each meter. Also mentions something about only meters configured as Modbus ID:1 or ID:2 will be detected?

I understand with Modbus RS485 is theoretically possible to have upto 32 meters each with own ID at full load? Easy to set individual IDs on models with displays.

I have only installed max of 2 meters on any system to date, single USB with ID 1 & 2, and a terminating 120ohm traitor at end with no problems.

Reason asking is have a project in which a Grid Parallel Victron based Storage system is to be considered, however there is already existing Grid-Tied Solar PV x 2 systems and a Wind Turbine Generator

Layout as below. Note no battery storage installed yet. All generation devices 3-phase.

Screenshot_20250827-221019
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I am wondering is it possible to install a Cerbo GX along with 4 X meters, e.g. Carlo Gavazzi EM530 as above, to get an understanding of site generation and usage with a view of installing a battery system at a later date. Would this work?

Meter 1 to monitor Grid Import & Export. Meter role set as Grid

Meter 2 to monitor PV system 1, role set as PV Inverter.

Meter 3 to monitor PV system 2, role set as PV Inverter as a above.

Meter 4 for wind turbine. Maybe set role as Generator?

Screenshot_20250827-223913
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Has anyone connected more than 2 x Energy Meters via RS485?

Alternatively to RS485 RTU has anyone use more than 2 X network connected Modbus TCP meters each with own IP address? Is that possible ot again does the 2 limitation become a factor?

Also has anyone implemented a Quattro setup with Grid and Generator and also a Grid-Tied / AC-Coupled PV Inverter. Keen to see how this is displayed visually on the new GUI. Can you see power of all 3 simultaneously?

Without having any Multiplus or quattro or battery storage installed, in curious to know if setup correctly would the Cerbo GX display and summarise import, export, PV generation, wind Generation (as Generator) and calculate load usage correctly?

Also wondering if 2 meters are connected as same role, does the Victron algorithms summate the data?

E.g. if 2 PV inverters and let’s say one is doing 10kW and one 20kW would 30kW be displayed?

Screenshot_20250827-222644
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Any advice welcome

2

I note In the documentation it states a GX device can be used with energy meters initially to collect data to enables system to be sized to requirements.

Screenshot_20250827-230831
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If anyone has done this with multiple meters would welcome feedback on how well it worked.

3

We have commenced a trial installing a Cerbo GX along with 2 Carlo Gavazzi Energy meters on a project site to asses power and energy usage from grid and performance of an existing Solar PV array.

Meter 1 EM530 with 100A CTs, set as Grid

Meter 2 EM540 65A direct connect, set as PV inverter

All works well, and dashboard is perfect on the connected Touch 70 display or via remote console, where measured Grid, measured PV and calculated load is correct.

However having a strange issue on VRM where the Grid meter seems to be duplicated and there is no power flow dashboard!

See images.

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PXL_20251009_134221955
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Now the VRM screenshot

Screenshot_20251009-224433
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Any ideas?

Thanks

6

Hi. I noticed this question as I have a similar problem I’ve just run into. I have a working ET112 meter on a Victron USB 485 connected to Cerbo. I have fitted another 3 EM111 AV81 meters to the board. I want to set them up as PV inverter, EV charger and Heat pump. I have confirmed they all work individually using the adaptor and I can also get them working on Modbus address 2. I am unable to get them to be recognised on address 3 and above though.

Is this a hard limitation that only addresses 1 and 2 are polled by the Cerbo, so it won’t even try address 3 and above. In this case, I assume the fix would be to add another USB to 485 adaptor so I would be using adaptor 1 address 1 for grid meter, adaptor 1 address 2 for EV, adaptor 2 address 1 for PV and adaptor 2 address 2 for Heatpump.

Ideally, I just wanted to use addresses 1,2,3,4 for the same setup just want to know if this is a non starter and I need the extra adaptor or if anyone has had success with an alternative setup?

7

Yes the cerbo only uses adress 1 and 2, so you need 2 usb converters for 4 meters

8

Thanks Marc for the swift reply appreciate it I’ve ordered another victron usb adaptor.

9

Finally got around to installing this.

Now have 2 victron usb 485 adaptors. An ET112 mixed with an EM111 on one adaptor. And two EM111 on the other. Took a bit of faffing to get working two of the EM111 were used and the parity had been changed from odd/no to even. They didn’t work at all like this even with them both set to even.

Also one of them refused to work when set to odd. In the touchscreen menu is a manual reset option. Did this and it sprang to life perhaps it turns off modbus if it detects a duplicate node address.

Anyway all 4 meters now working. Thanks