Gawd bless ya @OldSurferDude , that just about answered every question I have to date, I especially thank you for indicating whether the item named is a software or hardware product.
On reading into the Cerbo GX capabilities I was very impressed with its sophistication and, just as you said, I will have to break the complicated parts down into bite-sized pieces and build from there.
It started with an idea for a project, essentially to take data on battery state of charge (SoC) from the Cerbo GX and use an Arduino Nano or ESP8266 to build a strategy so that I would have sufficient hot water in the morning, consistent with having enough battery power left in the evening. Only on further inspection did it occur that the Node Red software built into the Cerbo GX could do this for me...and thus the possibility that a wireless hot water temperature sensor (transducer) could be fabricated to feed that data into the Cerbo GX; hence my path to here.
I've dabbled in programming in C, mainly through the Arduino IDE, and in a previous life part of my work involved programming PLCs for industrial automation, so I am somewhat familiar with 'tech', but I lost interest once most systems seemed to go Windows based. In the intervening years the 'tech' has moved on apace and has left me behind, which is why I've struggled to follow the jargon, akin to trying to fit the second piece in a large jigsaw puzzle. Once the fundamentals are there I'll catch on.

So please, kind contributors, be tolerant of the silly questions we newbies ask, we won't always be newbies, and I'll be back for sensors stuff once I've tamed the red-hot node and sorted out my LBQTTs

Best wishes....MM

Gawd bless ya @OldSurferDude , that just about answered every question I have to date, I especially thank you for indicating whether the item named is a software or hardware product.
On reading into the Cerbo GX capabilities I was very impressed with its sophistication and, just as you said, I will have to break the complicated parts down into bite-sized pieces and build from there.
It started with an idea for a project, essentially to take data on battery state of charge (SoC) from the Cerbo GX and use an Arduino Nano or ESP8266 to build a strategy so that I would have sufficient hot water in the morning, consistent with having enough battery power left in the evening. Only on further inspection did it occur that the Node Red software built into the Cerbo GX could do this for me...and thus the possibility that a wireless hot water temperature sensor (transducer) could be fabricated to feed that data into the Cerbo GX; hence my path to here.
I've dabbled in programming in C, mainly through the Arduino IDE, and in a previous life part of my work involved programming PLCs for industrial automation, so I am somewhat familiar with 'tech', but I lost interest once most systems seemed to go Windows based. In the intervening years the 'tech' has moved on apace and has left me behind, which is why I've struggled to follow the jargon, akin to trying to fit the second piece in a large jigsaw puzzle. Once the fundamentals are there I'll catch on.

So please, kind contributors, be tolerant of the silly questions we newbies ask, we won't always be newbies, and I'll be back for sensors stuff once I've tamed the red-hot node and sorted out my LBQTTs

Best wishes....MM

@nagelc Thank you for your reply. On reading from this site I indeed got the impression that it serves a narrow specific purpose, one in which I shall immerse myself in due course. My initial interest is educating myself in how data is 'packaged' for transport over the ether, and therefore whether various data from different transducers (sensors) share a common language.
My initial project seeks to garner data from several sources and combine them into a control strategy that will eneble me to better harvest the energy from my roof. The knowledge and experience gained will, naturally, be used to develop further projects, thus a sound knowledge of the fundamentals is ....... fundamental.
I will take your advice of searching elsewhere, but in the meantime if one of your members would kindly point me in the direction of a book or article on 'digital communications', 'ethernet comms made simple', or the like I would be greatful.

MM

Good evening all. I came here as one who has previously built and programmed simple devices with an Arduino back in 2020, now looking to implement some new project ideas and learn new skills.
Am I in the right place?
I have recently installed a battery storage system to augment my home solar PV. It has a Victron inverter and it works well, and there is a very interesting comms gadget attached via an ethernet cable called a Cerbo GX. This is Victron's connection to the internet and beyond. I noted that it has Node-Red installed within the Cerbo-GX, therefore I am interested in connecting new devices to it to enhance the functionality of the Solar-inverter-battery system.
I came here to read forum posts, tutorials and articles that will help me learn how to connect new sensors to the Cerbo-GX via its spare ethernet ports, however the jargon in just about every forum post makes it difficult for this newbie to comprehend. No doubt in time I'll learn what an MQTT thingie is (physical or virtual?), but until then please will someone guide me to an article, tutorial, or website that will allow me to learn the basics of 1) How to 'read' specific data over ethernet, such as battery state of charge or inverter temperature - all parameters I can display on the Cerbo-GX's display.
2) How to send data from elsewhere to the Cerbo-GX's ethernet port, and
3) An explanation of the data stream, ie is all ethernet data in the same format from whichever peripheral produces it.

I think that should do as a starter, apologies for the long-winded first post, at this stage I am ignorant of how much I don't know, but want to take the first steps.

Thanks for creating this site.....MM