IP addressinng

Hello all,

Greetings of the day

How I can set a static IP in a PLC?

I know how to give an IP to the PLC. All I need to know is using a router with internet access I need to give the static IP to it

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Amal Rank: 84

Asked 11 months ago

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Hi,

Before I try to help you, I have to know some things.

What kind of project you are working on? Pure educational? Private playing? The Watering system to the local fields? Small company? Big factory?

What is the worst thing who can happen if your machine fail or get mad? A puddle of water in the training lab? The garden door opens/closes unintended? Your fields are flooded, spilling away expensive seeds? Some machines get damaged? The factory exploding, wasting half of town with toxic liquids? (Not a bad joke. Things like this CAN happen if you let clueless people do dangerous work!)

Direct connecting PLC to the big bad internet is DANGEROUS. After connecting the PLC to the internet, the PLC can be accessed and disturbed by everyone from the net.

If the consequences are minor or nonexistent, you can do this. In this case I will try to explain or guide to do this.
If the consequences are major, man can also do this, but there have to be additional security work. Since you (apparently) not know the basics of networking, you are also not able to do security stuff. In this case I will not help, and you should really leave this to people wo know what they are doing.

Greetings
Stefan

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by Amal Rank: 84 on 3/11/2020 9:09:52 PM | Like (0) | Report

sir,
My project is simple I just need to get the data to my office area. Those data are not confidential. I'm using my PLC to get the readings of some meters and some relays that's all I need to do with that PLC. If in case of that kind of danger or something credential I can't do that because I'm a fresher in this area. If you can help me in this that will be very helpful for me

by Ordoban Rank: 30 on 3/12/2020 8:57:37 AM | Like (0) | Report

Ok, lets start.

Since ABB PLC does not know IPv6, we are bound to IPv4.
There are two kinds of IPv4 adesses.

Private IP address:
To give your devices in a private local network. You are free to chose this address, but to avoid confusion with Internet IP there are 3 areas reserved for private use:
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255

Internet IP address:
They are unique in the internet. As a private person you cannot get one directly, but usually your internet provider give one to your router.
(There are also internet provider who give private IP to there customers, in this case you are lost)

So, the router have two sides: the internet side and the private side. The router have one IP on each side.
The router does the translation between the private IP and the internet IP. By default this only works if the communication is started on the private side.
If the communication is started from the internet side, the router does not know how to translate the address ---by default---. (the translation process is called NAT https://en.wikipedia.org/wiki/Network_address_translation)
The PLC does not start the communication to the PC, its the PC who starts. So one way to make a communication to your PLC over the internet is to change the router settings.

The things you have to do:
1. Get access to the router settings.
2. Take a look at the IP addresses in this router. There should be a single public address.
3. Verify if the public address is inside a private address space. If this is the case you are lost.
4. Verify your router supports "port forwarding" (see https://en.wikipedia.org/wiki/Port_forwarding). If this is not the case, you lost.
5. Set up (or verify) your PLC to use the router as "gateway". There should be the routers private IP in the gateway setting of the PLC. If the PLC get its address dynamic from the router, this is the case by default.
6. Find out which ports to use for the PLC. Since I don't know your PLC, I have no idea about this. Maybe someone else can help?
For the first try we can also use a wide port range, or even forwarding the whole device. This should work, but increases the security risk.
7. Set up the port forwarding in the router. Create a relation between the PLC's ports and the PLC's IP. This is different for every router model, so I cannot describe this in detail. Just read the router manual, or goggle it.
8. On the PC side (assumed somewhere else in the internet) set up the routers internet address as the PLC's address.

There are two issues with this method:
- You are limited to one PLC. If you need more, you have to setup a VPN (see https://en.wikipedia.org/wiki/Virtual_private_network). A positive side effect of using a VPN is a far higher security. But it's complicated. Really.
- The internet IP of your router can change. They may change on every new connection of your router. They may change every 24 hours. So you have to look into the router every time you cannot connect to the PLC from the internet. But there is also a solution for this: Most routers supporting "dynamic dns" services. (See https://en.wikipedia.org/wiki/Dynamic_DNS)

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Ordoban Rank: 30

Answered 11 months ago

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