Once you sign in you will be able to subscribe for any updates here

ET340 RS485 to USB connection problems

Looking for some assistance on getting an ET340 working with a CCGX, CCGX is V1.74 does this support ET340 as menu looks to be different to what manuals indicate. I'm using 5M USB to RS485 Victron cable, no interference across installation, orange,yelow and black as instructed, CCGX does not see ET340 at all, plugged into USB host port on CCGX, no red or green flashing light (only on initial plugging in, then only get a solid red led (not the traffic led). Tried connecting ET340 to a Win 7 home PC with Carlo UCS7 software but that doesn't appear to work either. Have tried multiple USB ports, various USB to RS485 cables that I have on hand, linked in 120Ohm resistor on ET340. No luck at all, thinking I have something DOOB but thought I'd throw it out there for advice.

surefk asked

0 Answers

Is it possible to send data via RS 485 from a GX-device?

We would like to power a PCU (https://leica-geosystems.com/products/leica-pegasus-trk/product-overview/control-unit) from a battery pack that is monitored by a BMV712 and a Venus GX. The PCU needs information about state of charge off the battery and voltage. This can only be send to the PCU via RS 485. Is there a possibility to send information via RS485 from a Venus GX to the PCU? Or can we better change to a raspberry Pi with Venus OS installed?

leenderthameete asked

0 Answers

Possibility to change EM540 modbus driver to read consuption with higher resolution

I just found out, that the modbus RTU (RS485) driver for the EM540 energy meter in the current venus OS 3.00~14 is reading the register address 0x0034 (kWh (+) TOT) with the length of 4 bytes (INT32) as the total energy (Value weight: kWh*10). The resolution is 0.1kWh. This seems to be a small resolution for small households as for example the hourly consumption is around 0.2-0.3 kWh. So in the VRM portal the statistic is relative coarse...

My suggestion is not to read register 0x0034 but 0x5000 with 8 bytes length (INT64) as the total energy (Value weight: Wh) instead. This would give a resolution of 0.001kWh and would be much more accurate.

I got these information from the Carlo Gavazzi EM540 communication protocol PDF available from the internet. Could that change be implemented in future versions?

And as the duty cycle for the rs485 bus with 9600baud is quite high for the high speed update rate of the EM540, would it be a possibility to add a higher baud rate option? E.g. 57600 baud?

christiangurk asked
christiangurk edited ·

0 Answers

Energy Meter ET112 communication link

Like many before I have been challenged by installing an ET112 "grid meter" at mains AC entry point when my whole solar setup is in an outbuilding around 40m away. Hard wired communication back to a Multiplus 2 GX is just way too complicated, and would require laying underground conduit to hide cable runs across a large parking area. I did consider the Zigbee option, however, from my experience of trying to get a decent extended WiFi signal to my outbuilding I am not even sure the Zigbee would guarantee a solid connection (it is effectively a wireless mesh system operating on the same 2.4GHz as WiFi. At that frequency passing through 3x 25cm solid walls over the distance required is probably on the edge of operation?).

My thoughts turned to a RS485 radio link. At this stage I know I am subject to scrutiny and I make no guarantees that this would suit everybody's situation. If I could I would go for a hard-wired link... but I can't. I absolve myself from all liability if anyone decides to copy my project.

I have done some projects with LoRa in the UK so the available 868MHz band is well known to me. I stumbled across a RS485 transceiver board on ebay (....don't you just love it?), made by our friends in a different time zone. So, I purchased 2 of these boards to play around with. They use FSK modulation and make the board in 433/868 MHz versions (check your country rules!!). Ideally they run on 5v and the manufacturers claim a free air (line of sight) range of 500m. They appear to do what they claim.

The next part of the puzzle is the link to the GX device. Victron "recommend" FTDI UART chip based serial communication by implication (....that is what their standard connection cables seem to be based on?). There are 2 other UART chip devices in general circulation the CH340 and the CP2102(SiliconLabs). From what I have found the Victron equipment does not natively communicate with CH340 devices (you need the drivers installed). The CP2102 chip works with a Venus GX I have on a raspberry pi system and also with Multi 2 GX (which effectively has a Venus inside). I have not tested with Cerbo GX but there is no reason to assume it will be different since the software is all Linux based?

The USB to RS485 device I bought was the DSD Tech SH-U10. Which is a dongle that plugs into my raspberry pi. Be aware that this will not fit within the Multiplus 2 removeable protection panel over cable entry. You could just get a USB extender cable so that the dongle is outside or, as I am going to do, buy the DSD Tech SH-U10L which comes as a connection dongle on the end of a USB cable... much neater solution.

The transceiver uses less than 30mA at 5V so at the Victron end mine is powered off the DSD SH-U10. However, I have built small mains powered 5V DC power supplies into my devices so that I can run the radio link off a fused spur at my consumer unit end. In fact I used the opportunity at the grid entry point to install a Mains isolator between electricity board meter and house consumer unit in a small secondary consumer unit (designed for garages/outhouses etc). That also neatly houses the ET112 meter, since there was no space left in the main consumer unit.

So, that's it. I 3D printed some ABS boxes for neatness and to keep it housed safely. Although I only "need" the power supply at one end I have just printed the same box at both ends. I have played around with different cable options and have decided that standard internal BT telephone cable is a good option, it is just 2x twisted-pairs within the same cable. Of course this has not been tested to extreme but it has been soak tested for a week or so and appears to connect flawlessly?



gazza asked
gazza edited ·

0 Answers

Carlo Gavazzi EM111 feed-in feedback loop


I recently installed an EM111 Carlo Gavazzi meter to monitor my grid connection point to limit my grid feed-in.

To make the meter work, I had to change the meter parameter "Measure" to "b", such that reverse power flow would read as -ve and forward as +ve. When set up like this, the Victron system works perfectly.

However, after a couple days, I am finding this "Measure" parameter changes itself back to mode "a". When it does this, all power, even feeding-in to the grid, is labelled as a +ve power flow. The Victron sees energy being consumed, and then raises it's feedback to combat it. The system is actually feeding in this power, so this results in a positive feedback loop until the Victron maxes out.

Would Victron be resetting this parameter via the modbus RTU? I have seen no indication in the EM111's manuals that they would self-reset, so I am at a loss. Any help would be greatly appreciated!

My system is as follows:


Quattro 10KVa

EM111 connected to RS485-USB adaptor in CCGX

2x 150/45 BlueSolar MPPTs

400Ah 48v Lithium CANBus Battery Set.

andyandy26 asked

0 Answers

Intergration Of Victron Cerbo and Solaredge Meter

Intergration Of Victron Cerbo and Solaredge Meter

SE meter operates on RS485

Ebrahim Railoun asked

0 Answers

EM24 with Backlight


is there a special version of the EM24 (RS-485) Energy Meter with backlight available? The one I got here unfortunatly dosn't seem to have backlight. Maybe CG has a special version with backlight compatible with victron?


steffenp asked

0 Answers

ET340 at single phase system (L1) and PV at L2 - RS485 communication breaks at night


I run a grid connected ESS system:

MultiPlus II (48/3000), CCGX, ET340 meter connected via Victron RS485 to USB interface.

1kWp PV system and BMZ li-ion battery.

I use a ET 340 meter: All house loads via L1 and PV production on L2 ("Single phase dual function" as shown here: https://www.victronenergy.com/live/energy-meters:et340).

Multi Plus II is connected at AC in.

The system runs well during day times. But at night/early morning the meter looses connection to the CCGX (via RS485 adapter) and doesn't reconnect automatically. Both grid and PV power aren't not available anymore and the system stops operating (no charging or discharging).

After a restart of the CCGX the system runs well again (until next night).

Any idea how to fix this problem.

Many thanks, Bernd Lienemann

junk asked

0 Answers

Top Contributors - Community Supporters

Alexandra avatar image Alexandra 243 Answers & Comments
nickdb avatar image nickdb 161 Answers & Comments
Matthias Lange - DE avatar image Matthias Lange - DE 150 Answers & Comments
kevgermany avatar image kevgermany 147 Answers & Comments
klim8skeptic avatar image klim8skeptic 138 Answers & Comments
JohnC avatar image JohnC 94 Answers & Comments
steffen-graap avatar image steffen-graap 69 Answers & Comments