Hi,
I have an ET340 installed and want to connect it to a Cerbo GX.
I expected that I could connect them together using an Ethernet cable. But whatever input I use on the Cerbo GX the ET340 is not detected.
What am I doing wrong?
Best regards Maarten
Hi Maarten,
looks to me as if you were connecting the ET340 Modbus directly to the Cerbo CAN. I did not check the pin assignment, but anyways these are different physical layers, so I do not think this will work.
For reference, I looked at these documents: ET340 and Cerbo GX.
To be continued, because I am not allowed to add more than 2 links.
And I am not allowed to reply two times without some delay 
What you need is probably described here: Energy Meter Manual, section 2.2.1. You need a USB to RS485 Serial Converter - some electronics, not only a simple cable.
Best Regards,
Klaus
The RJ45 ports on the ET340 are RS485, just like the screw terminals at the bottom of the device, they are all in parallel. Any RS485-to-USB adapter should work.
Theres also all sorts of network cables available, for example S/FTP, means that the cable is shielded by braiding already
Thnx for all your replies. @chrigu @Klaus
I will look for a RS485-to-usb adapter.
@chrigu The cable I used is a CAT-6 shielded ground cable.
But because it is next to a 3 phase ground cable, plus 2 other 1 fase current bearing ground cables, I added the external “faraday cage” and connected it to ground in the junction box (meterkast in Dutch, don’t know if the English term is correct that I used). Hopefully enough to not have interference.
I have a generic usb-rs485 converter and connected the orange wire from the cat5 cable to B, the orange/white wire to A and the brown wire to GND. I also switched A an B around. According the the table in the ET340 manual. But I cannot discover the device in the modbus TCP/udp device section.
Firmware version of ET340= 4.32
TCP modbus enabled
Tried all USB ports
Converter is blinking when in USB port, so it is receiving power.
What am I doing wrong?
Why you don’t just use the original cable:
And wire it like it is described in the manual?
https://www.victronenergy.com/media/pg/Energy_Meter_ET340/en/installation-and-configuration.html#UUID-a8f6666a-c43a-5d66-6b6a-af04bb06313d
Earlier reply said ‘any’ converter should work. And this would be a 3 euro converter from AliExpress. Worth a try if any converter should work. So if anyone has used one an it works I would like to know how.
Otherwise I will have to buy an original one of course.
In the old community we had a few reports that cheap converters doesn’t work well.
Ordered the one you suggested to avoid alot of hassle and problems in the future. Thnx for the tip
Bought an original cable.
Checked the Ethernet cable with a cable tester, tested good, so Ethernet cable is 100%.
Still no joy, ET340 not found in the ‘modbus TCP/UDP device’ scan.
Tried all usb ports, and both “ethernet” ports on the ET340.
Any tips?
Hello,
you need to connect the RS485 wire directly on the ET340 like the picture below…
The RJ45 port are used only to chain units together…
Xavier.
Ow really, that was not clear for me. Will do that
You don’t like to read manuals?
The link to the Victron manual was posted a few times.
This is from the original manual of the ET340:
It is not that I don’t read manuals, it is that the manuals are not clear enough and different depending on which you look at. Or I am to dumb, that is also a possibility 
In the Dutch manual at least, I did not find it clear that I cannot connect through the ethernet port, and in that manual they clearly state to use the orange, orange/white, and brown cable.
It says suggested wire color if you use a normal network cable to extend the RS485
You need to connect it to pin 4, 5 and 8 whatever color that is in your wire.
@M_Lange A question: Are you saying that I can use the ethernet port on the ET340 but need to connect the USB converter to different pins on the Ethernet wire?
Because Xabi said those ports are only used to chain multiple units together.
Because when I have to connect the eth wires to the terminal outputs I could potentially use any twisted wire pair from the cable to connect the et340 with the usb converter.
I never used that RJ45 ports, only the screw terminals 8/9/10, but I guess if you use the correct pins it should work.
On that adapter try move orange to 4 and yellow to 5.
Helo,
let’s have some reading …
or
Energy Meter ET340 manual (solarmarkt.ch)
In Fact this is not written…(So I’m wrong) but the RS485 is availble on port 8-9-10…
Pin to connect thru the RJ45 plug.
Xavier
One other interesting point … installing the Carlo Gavazzi app on the computer could help to check the Setup or cheng some setup too…
And you have to connect it to the computer with the RS485 adapter…
here the one I use to have on my differents setups
on one RV
