question

Serge Della Signora avatar image
Serge Della Signora asked

Energy Meter ET112 + Cerbo GX

Hello,

It is recommended in the ET112 manual to use an RS485 to USB cable. This is what I'm going to do to be Ok.

But I read at the bottom of page 4 (pdf): "The red, green and brown wire coming out of the USB to RS485 cable are not used. Note: You can wire on a RJ45 plug which can plug into the front of either RJ45 socket of the Energy meter, it has the same pin out. "

It is understood that it is to lengthen the cable.

I'm curious and my question is in two parts:

- what are the two RJ45 sockets on the front of the ET112 for?

(Matthis replied in another post that these are not ethernet sockets).

- can we connect an ET112 and a Cerbo GX in RJ45 to RJ45 (Cerbo's BMS-Can socket)?

Thank you in advance for your answers which may help other people.

Kind regards

Energy Meter
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5 Answers
michelg avatar image
michelg answered ·

Hi Serge ! May be a picture is worth a thousand words...

20200914-144529.jpg


20200914-144529.jpg (300.8 KiB)
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betaoil avatar image
betaoil answered ·

I made my own rj45 and plugged it in to the front, you can work out the pins quiet easily

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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

"can we connect an ET112 and a Cerbo GX in RJ45 to RJ45 (Cerbo's BMS-Can socket)?"

No definitely not, the ET112 must go via the Victron RS485 to USB adapter, with the USB end plugged into the Cerbo GX.

It is possible to crimp an RJ45 plug to the the orange, yellow and black wires of the RS485 to USB adapter, and plug that RJ45 into the ET112, but it is not recommended - just another potential thing to go wrong (bad crimp, wrong pins, etc).

It is recommended to use the clearly labelled pin terminal connections below (as shown in the manual and @MichelG's image.

Generally speaking in a Victron installation those RS485 RJ45 sockets on the front of the ET112 are not used.

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Serge Della Signora avatar image
Serge Della Signora answered ·

Thank you Michel and Guy for your answers.

My question was mostly based on curiosity and I think a lot of people have wondered about these sockets on the front of the ET112.

It is necessary to stay on the good old method of the screw terminal block which is safe instead of risky to destroy the Cerbo GX and / or the ET112.

The photo is also very good because in the pdf manual it is necessary to enlarge the image a lot to see the wires on the screw terminal block.

Very good weekend to you.

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patricknl avatar image
patricknl answered ·

If you use a long cable to run the ET112/340 to a GX device it's best to use an sFTP cable (shielded fully shielded twisted pairs). These are the best shielded cables out there. This reduces chatter and noise on the communications line.


I'm running a 12m Cat7 sFTP cable without any hickups whilst the other meter on the stock 1.8m RS485-USB cable sometimes fails.

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sales-1 avatar image sales-1 commented ·
I've been going round and round with this. Using 15m of Cat 6 cable have tried using terminators as suggested in manual with NO JOY... Very frustrating. Am I missing something in the set up? The Manual says that the ET112 will just show up in the Energy Meter Tab. Help would be appreciated.
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richh avatar image richh sales-1 commented ·
Hi, did you manage to get a connection. I'm having the same issues. ET112 is approx 12m from cerbo gx, had a swa cable with cat5 cable built in, but ET112 would not show up.

I have tried 120ohm resistors at the ET112 end, no change, shortened the USB cable to 20cm, no change.

Bought a new 15m screened Cat7 cable and ran separately away from all power cables, still not showing up on display.

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usernamepasswordbs avatar image usernamepasswordbs richh commented ·
I've got a non-screened alarm-type cable of about 30m and it works fine. Check the usb is not plugged into the 3rd usb socket of the cerbo. Also the 3 wires are correct at the ET112.
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richh avatar image richh usernamepasswordbs commented ·
Hi, checked all the connections, all correct, also used the ET112 software and where the usb which plugs into the cerbo, is plugged into my laptop, I can see et112 working and check all tbe settings, plug it back into the cerbo gx, still not showing up, so et112 is working and connections from it to the usb are working.

Lost as to what is the problem.

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daza avatar image daza richh commented ·
Have you tried checking the continuity of the ethernet cable making sure that you get continuity from one end to the other on all your single ethernet cables
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richh avatar image richh daza commented ·
Hi, the cable must be fine as I can use the Carlo Gavazzi software and see the meter working, when the usb is plugged into the cerbo gx, it does not recognise it, I've tried both the middle and outer USB port, the screen uses the last port next to the hdmi port.
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usernamepasswordbs avatar image usernamepasswordbs richh commented ·
Only guessing and maybe this has been already suggested but look in RemoteConsole/Settings/Energy Meters and take a screenshot of the settings and post it up here. Someone might be able to spot something awry.
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daza avatar image daza richh commented ·

I would check your connections on the ET112 are actually making contact with the ET112 terminals and that the correct colour per number on the ET112 are used also check the connections from the RS485-USB cable to the Ethernet cable are connected and to the proper corresponding cable/colour that Victron recommend

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smine avatar image smine commented ·
Hi, always good to use some ferrite beads on the Cerbo GX side. I install them on each incoming cable, on the Cerbo GX. And it isn’t even a bad idea to install one on the other end of the cables too…

All the best.

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eamonno avatar image eamonno commented ·
Hi Patrick….. I’m trying to connect two ET112s (AC & PV). Both are 15m from the Cerbo. How did you connect your Cat7 cable, please?
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2mas avatar image 2mas eamonno commented ·

Have you tried putting 2 ET112 on one Cerbo?

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l81ker avatar image l81ker 2mas commented ·
yes, it works fine. two ways to do it.


1. string them in series (you need to change the address of the second one using Carlo Gavazzi software)

or
2. connect each with it's own USB back to the cerbo.

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