IP Addresses & Solar Panels: How Does It Work?
In the world of the Internet of Things (IoT), everything and anything is being connected to the internet: Not just smartphones and PCs, but also televisions, refrigerators, and inverters. Online monitoring of solar panels has many advantages, but it can sometimes go wrong. In this article, we try to explain how routers and IP addresses work, and what you can do if communication doesn't run smoothly.
All devices that communicate with each other must have their own unique identification code to ensure that the data reaches the right destination. For example: You are sitting behind the computer and typing in the website address of The Solar Factory. The data from The Solar Factory must travel from the server, via the internet, to your home, and then be displayed on your PC at home, not on your daughter’s iPad who is browsing Instagram.
The devices are all uniquely identified thanks to the IP address (IP stands for Internet Protocol). Each device, whether it’s a PC or an inverter, must have its own IP address to be found within a network.
4 Groups of Numbers
IP addresses consist of 4 groups of numbers with periods in between, such as: 80.63.141.25. The numbers range from 0 to 255, but do not exceed this. The reason for this is that computers use these numbers in binary form (meaning translated to only 1s and 0s), and the maximum length of these numbers in binary form is 8 digits. The highest number in binary form is therefore: 11111111, which equals 255 in decimal.
We have 4 numbers ranging from 0 to 255 to create IP addresses, but with billions of devices now in the world, there are never enough unique IP addresses for every device. So, what now?
Local Networks
To solve this problem, the internet is divided into many smaller local networks (LAN, which stands for Local Area Network). Every household with an internet connection has such a LAN. The modem/router serves as the gateway to the outside and has its own unique IP address on the internet, but the devices within the house have an IP address that is unique only within the house. The modem/router is the one that knows which device has which IP address, and directs all information to the right address.
An example: You are sitting behind the PC and typing the address of The Solar Factory. This means you are requesting your computer to bring up the website. The computer sends this request to the router, which is the gateway to the outside. The router sends the request outside, to the server where The Solar Factory’s website is hosted. The server then sends the website data back to the router, which in turn sends it back to the computer from where the request came.
The Router Has Two IP Addresses
The IP addresses within your home network look very different from those outside of it. For example, your PC might have IP address 192.168.0.5 and send a request to the router with the IP address 192.168.0.1. The request reads: "Please send the website of Zonnefabriek to me, the computer with address 192.168.0.5." The router, as the gateway for the home, has two different IP addresses: One is visible only within the house, and the other is visible from outside (from the internet). Let’s say the latter is 80.93.42.11. The router’s request to the Zonnefabriek website will then be: "Please send the website of Zonnefabriek to me, the router with address 80.93.42.11." The Zonnefabriek server sends the requested website to the router, which then knows it needs to forward it to the computer with address 192.168.0.5. And that’s how the website appears on your computer screen.
All devices within the local network need to have a unique IP address within that network and must be able to communicate with the router to get data from the home to the internet and vice versa. The router is usually the one that determines which device gets which address. When a new device is added to the network, and it connects to the router, the router decides which IP address to assign to the new device. This assignment of IP addresses by the router is called DHCP (Dynamic Host Control Protocol), making life easier. For example, you don’t have to choose which IP address your iPad should get; the router will decide that for you.
DHCP: The Router Is the Boss
This is also how inverters work: An inverter installed in your home will be connected to the router, either through a network cable or via a wireless Wi-Fi connection. The router detects a new device in the home and assigns it an IP address to ensure smooth communication. The router is the boss; if a new device is added, it can reassign IP addresses and give everyone a new IP address.
As long as the inverter has a valid IP address, it can send data through the router to the internet so you can monitor the performance remotely. However, sometimes the router "forgets" that there’s an inverter in the network. This means the inverter doesn't get an IP address, and no data transfer is possible. If this happens with a PC, simply turning it off and on again will make the router recognize the device and assign an IP address. The same applies to inverters: turning the device off and on usually solves the issue quickly.
But if the problem keeps recurring, it can be frustrating to keep resetting the inverter each time. In such cases, you might choose to set a fixed IP address for the inverter: The router will no longer be in charge and must accept that the inverter always has the same IP address within the local network. This way, communication won’t break down so easily.
Static IP Address: Remember It Well!
Setting a static IP address requires some effort but is manageable. So, why not always do it? The problem is that inverters last much longer than routers! If you’ve set a static IP address for the inverter that works with a specific router, it might not work with a new router. This means if the router is replaced (because it broke down or because you changed your internet provider), the inverter’s IP address will need to be changed. And that could be a hassle down the line!
That’s why at Zonnefabriek, we are cautious about setting static IP addresses. However, if communication issues happen too often, we’d be happy to help you explore all possible solutions. Setting a static IP address could be one of them. You can learn more about this on the SMA service page. Just don’t forget to write down the IP address you set! It could come in handy years later when you get a new router!
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