question

matt1309 avatar image
matt1309 asked

Ct clamp over ip ethernet.

Anyone know of a analog to TCP/IP transmitter/receiver?

Ct clamps are £15

Em24 £200+

So anyone know of a solution of sending ct signal over ip and then back so I can send it over ethernet. With parts less then £185....


Thanks,

Matt

Energy Meter
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9 Answers
matt1309 avatar image
matt1309 answered ·

If anyone stumbles upon this is the future. I ended up going with ET112 and buying Rs485 to TCP server and client adapters (I think i got them from pihut, waveshare ones, Nothing special but seem to be working fine for transfering meter data other ethernet (TCP not just a cat5/6 wire as i also use the wire for internet connection in shed).

I did try reading into transfer ct clamp signal via a raspi or arduino to the shed via internet and then simulating CT clamp at the shed side but it was above my knowledge level so i bit the bullet and paid the painfully expensive price for ET112 meter.

4 comments
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fox1980 avatar image fox1980 commented ·
Hi Matt

I have purchased the same equipment from PI Hut, can you tell me what setting up was required on a software level to get this working please as I guess it is not plug and play.


Thanks

Dave

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matt1309 avatar image matt1309 fox1980 commented ·

Hi Dave @Fox1980


Snippet of my sender and receiver waveshare settings below.


Connect et112 into the sender and sender to your Internet/router.

Similarly on the waveshare receiver plug this into network And then a into a rs485 to usb device on the receiver. The USB then into your cebos gx/raspi. This will then show up as a normal direct rs485 device.

I would setup static ip for both your sender and receiver in your router. As you can see mines 192.168.3.110 and 111

If you get disconnections of the meter tweak with the reconnect settings in waveshare to get it to auto reconnect quickly in the event there's Disconnects.


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matt1309 avatar image matt1309 fox1980 commented ·

Server screenshot-20221112-214217-chrome.jpg

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matt1309 avatar image matt1309 fox1980 commented ·

Client screenshot-20221112-214203-chrome.jpg

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lifeingalicia avatar image
lifeingalicia answered ·

Victron does not recommend it but you can extend the clamps with high end headphone extensions. I use a 3 meter one works fine. I read a comment someone using a 30 meter extension probably extreme.

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matt1309 avatar image
matt1309 answered ·

Thanks for the response. I'd spotted a few of those posts that mention that method.


I was looking more to convert the signal to TCP/IP. I think others have jerry rigged other IP/ethernet meters to be read by venus os. For me the inverter is in shed. Shed has power run to it and ethernet. Running an additional rs485 cable would mean 100m of digging. I found an rs485 to tcp converter on pihut. Going to try my luck with one of those.

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raymiller avatar image
raymiller answered ·

You might try to use the spare pairs in the existing cable, LAN cables usually only use 2 of the 4 pairs in the cable. Using an RJ45 splitter at either end of the cable can give you access to the spare pairs.

The downside is the coupling between the two sets of pairs which may cause interference with the signal quality but maybe worth a shot to test it out.

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lifeingalicia avatar image
lifeingalicia answered ·
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matt1309 avatar image matt1309 commented ·

@Lifeingalicia Hey i ended up using two of the below items. One as a "sender" (aka a client) and one as a receiver (aka a server). To go RS485 -> LAN -> RS485 to the Cerbos/(raspi in my case). Works well and allows me to still have internet at the shed where inverter is rather than using the cat6 i burried for RS485 alone.


Industrial Serial Server - RS485 to RJ45 Ethernet– The Pi Hut

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chrisp avatar image chrisp matt1309 commented ·
Hi thanks alot for your comment. Was just seeing if I could pick your brains. Sounds as if I’ve got a similar problem.


Solar array is a fair distance from the main income. Where I need to get a ct meter on the mains.


I can’t run a cable. But I do have a switch Lan connection at both ends. Did you manage to connect the ct then run it down the Lan after ? Or how did you do it in the end. Been told couldn’t use the lan because of the current. Any advice would be great thanks alot Chris

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matt1309 avatar image matt1309 chrisp commented ·

Hi @Chrisp

I resorted to using RS485 to TCP/IP converts. So ET112 to RS485 to TCP/IP converter as a sender. However there may be better options for you now.


if you go my route there's two options.

1. write a custom driver in python to get the TCP/IP data into Venus os (there's probably templates on github for this).

Or

2. You get a second RS485 to TCP/IP converter to go back to rs485 (what i did)

ie a sender and receiver over lan.


RS485toTCP <-> LAN <-> TCPtoRS485 -> gx device.


I didn't realise the custom driver was possible at the time so I bought 2 RS485 to TCP/IP adapters (from waveshare) and configured as above.

One to convert rs485 to TCP/ip and then another to convert back from TCP/IP to Rs485 to go into gx device via rs485 to usb connector (as though the et112 was going directly into gx device).

The solution is not perfect and does disconnect for a few seconds every so often but it's reliable enough for me.

The waveshare devices have timeout settings to help auto reconnect quickly in the event the connection is lost. I've been tweaking them overtime and the impact of a disconnection is minimised now.

Personaly if i was doing it again i'd try run another cat6 and use ct (et112 has lag)

Another option I've seen on the forum (but not used/tested) is using shelly power monitors on incoming grid supply and custom venus os drivers to get the data into gx device.

If you go waveshare route i can share the settings I have if useful.

The shelly power monitor option might be worth a research though, seems quite good. I've not used or tested this though: GitHub - fabian-lauer/dbus-shelly-3em-smartmeter: Integrate Shelly 3EM smart meter into Victron Energies Venus OS

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chrisp avatar image chrisp matt1309 commented ·

Hi Matt, hope your well just wanted to double check guessing gx is in this case the inverter.


Ct clamp into ET112 -RS485toTCP <-> LAN <-> TCPtoRS485 -> ET112 gx device



Hope that makes sense.


Thanks a lot Chris

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matt1309 avatar image matt1309 chrisp commented ·
If you have GX model inverter then yes, otherwise would be an external device like a cerbo gx or raspi running venus os.


I believe others have had success not using the TCPtoRS485 and reading the data via TCP in the GX device but this does need custom driver/python knowledge.
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lifeingalicia avatar image
lifeingalicia answered ·

@matt1309 Thanks for the info good to know

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gazza avatar image
gazza answered ·

I also looked at this @matt1309 . As I see it most of the complexity is in converting the output of the CT clamp into RS485 Modbus, since it is the current that is conveying the info, rather than just a voltage? There are Current to RS485 converters (or even CT clamps that output RS485 modbus encoded data), however they are not cheap either! I thought about using a "matched" burden resistor to get the same voltage as would be seen at the Victron GX input then making an A-to-D radio link and then converting D-to-A at the shed end just to plug directly into the CT clamp extension socket to "simulate" the CT input?

However, In the end I did buy an ET112 and built a simple radio link (868MHz), I didn't use the TCP/IP approach as getting WiFi alone to my shed was tortuous and flaky. It also wasn't easy to provide an ethernet connection at my consumer unit.... so, I did this:-
https://community.victronenergy.com/questions/148423/et112-communication-link.html

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adam-kramer avatar image adam-kramer commented ·
@Gazza I am looking to implement something similar to this at my house. Please hit me up on LinkedIn if able, I'd like to potentially purchase a setup like the one you described. /adam-m-kramer. Thanks
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gazza avatar image
gazza answered ·

Hi Adam. Did you mean the 868Mhz/ET112 option that I D.I.Y'd ? I am not a big Linkedin user but happy to swop email or use WhatsApp... ? Not sure there is a way to do private messages via VRM community ? The heart of the radio link that I used was based around this:- https://www.ebay.co.uk/itm/275242487267?var=575513259567

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dmsims avatar image
dmsims answered ·

Simple way of doing this is to use a Shelly 1EM (with the added advanatge of being able to use a second CT if you have an EV). No converters and no lag!

screenshot-2023-07-20-112424.png


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