Connection setup Docker container linux

[runtimevic]

Hello,
I'm looking for documentation on how to create a Docker container on Linux with a small example to communicate with ads-client.
If possible, I'd prefer not to use a ads-router, or is it mandatory to use routing in a Docker container with Linux?

Best regards Víctor.

[crishoj]

You mean how to get TwinCAT to run in a virtual machine?

Jakob Sagatowski has a video you might find useful: https://www.youtube.com/watch?v=mbQSRNMJRz8l

[runtimevic]

You mean how to get TwinCAT to run in a virtual machine?

Jakob Sagatowski has a video you might find useful: https://www.youtube.com/watch?v=mbQSRNMJRz8l

Hello @crishoj

Is it possible to create a container on a Linux host without an ads-router?

[crishoj]

Is it possible to create a container on a Linux host without an ads-router?

I have not tried this myself, but I think it is equivalent to Setup 3 in the diagram here:

[jisotalo]

I have done this in the past and it works but requires some work to set up.

See the following for some info

• https://github.com/Beckhoff/TF6000_ADS_DOTNET_V5_Samples/tree/main/Sources/DockerSamples
• https://github.com/Beckhoff-USA-PM/AAG_Beckhoff_RT_Linux_Containers_Examples/blob/main/ADS/HostAdsRouterSetup/HOST_CONNECTION_ADSROUTER_GUIDE.md

Basically your docker network needs to have ADS router running (container like this) with different router port than 48898, e.g. 48900. Then the clients in docker network need to connect to that router, which then forwards packets outside of the docker network.

To connect to a different router (port 48900), use settings routerAddress and routerTcpPort

Unfortunately I don't have any direct example and I don't really have time to create one.

[runtimevic]

I have done this in the past and it works but requires some work to set up.

See the following for some info

• https://github.com/Beckhoff/TF6000_ADS_DOTNET_V5_Samples/tree/main/Sources/DockerSamples
• https://github.com/Beckhoff-USA-PM/AAG_Beckhoff_RT_Linux_Containers_Examples/blob/main/ADS/HostAdsRouterSetup/HOST_CONNECTION_ADSROUTER_GUIDE.md

Basically your docker network needs to have ADS router running (container like this) with different router port than 48898, e.g. 48900. Then the clients in docker network need to connect to that router, which then forwards packets outside of the docker network.

To connect to a different router (port 48900), use settings routerAddress and routerTcpPort

Unfortunately I don't have any direct example and I don't really have time to create one.

Hello @jisotalo ,
So, to get an app working in a Docker container communicating with a PLC using ads-client node.js,
do I need to create another container that acts as a router with the links you provided?
Therefore, is setup 3 not valid for Docker?
Sorry to ask again, I just want to be clear on this.

[jisotalo]

Yes - if I recall correctly. It might be possible to run one ads-client connection directly from docker but I'm not sure.

Issue is that the TwinCAT router only accepts loopback connections from localhost, not docker network (it will reject them). That's why the router is usually needed.

Again - I might be wrong. I have only used with docker using a separate router inside docker network.

[runtimevic]

Yes - if I recall correctly. It might be possible to run one ads-client connection directly from docker but I'm not sure.

Issue is that the TwinCAT router only accepts loopback connections from localhost, not docker network (it will reject them). That's why the router is usually needed.

Again - I might be wrong. I have only used with docker using a separate router inside docker network.

Hi @jisotalo ,
Thank you so much for your response.
We will conduct our tests and report back...

[victordm-dev]

It works with a Docker Linux container without a router in Docker.
The issue can be closed...

[jisotalo]

Great! Could you please paste the docker and ads-client configs here? It would be super helpful.

Thanks!

[victordm-dev]

dockerfile:

FROM node:20-slim

WORKDIR /app

COPY package*.json ./
RUN npm install

COPY . .

CMD ["node", "--env-file=.env.docker", "index.js"]

---

docker-compose.yml

version: '3.8'

services:
  ads-client-app:
    build: .
    container_name: ads-client-app
    restart: unless-stopped
    env_file:
      - .env.docker
    network_mode: host
    # network_mode: bridge (si host no funciona, vuelve a bridge)

---

index.js

const { Client } = require('ads-client');

const client = new Client({
    localAmsNetId: process.env.LOCAL_AMS_NET_ID || '192.168.0.10.1.1',
    localAdsPort: parseInt(process.env.LOCAL_ADS_PORT) || 32750,
    targetAmsNetId: process.env.PLC_AMS_NET_ID || '192.168.0.102.1.1',
    targetAdsPort: parseInt(process.env.TARGET_ADS_PORT) || 851,
    routerAddress: process.env.PLC_IP || '192.168.0.102',
    routerTcpPort: parseInt(process.env.ROUTER_TCP_PORT) || 48898,
    rawClient: false,           // Permite conexión sin validar el runtime del PLC
    allowHalfOpen: true,       // Permite conexión aunque el PLC esté en config mode
    timeoutDelay: 10000,       // Timeout aumentado a 10 segundos
    hideConsoleWarnings: false // Mostrar todos los warnings para debug
});

async function main() {
    try {
        console.log('Intentando conectar al PLC...');
        console.log(`Router: ${process.env.PLC_IP || '192.168.0.102'}:${process.env.ROUTER_TCP_PORT || 48898}`);
        console.log(`Target AMS Net ID: ${process.env.PLC_AMS_NET_ID || '192.168.0.102.1.1'}:${process.env.TARGET_ADS_PORT || 851}`);
        
        await client.connect();
        console.log('✓ Conectado al PLC');
        
        // Verificar el estado del sistema
        const state = await client.readPlcRuntimeState();
        console.log('Estado del PLC:', state);
        
        // Bucle para leer y escribir
        setInterval(async () => {
            try {
                // Leer el valor actual
                const data = await client.readValue('MAIN.counter');
                console.log('Valor leído:', data.value);
                
                // Sumar 1 y escribir el nuevo valor
                const nuevoValor = data.value + 1;
                await client.writeValue('MAIN.counter', nuevoValor);
                console.log('Valor escrito:', nuevoValor);
            } catch (err) {
                console.error('Error en el bucle:', err.message);
            }
        }, 2000); // Ejecutar cada 2 segundos
        
    } catch (err) {
        console.error('❌ Error de conexión:', err.message);
        console.error('Detalles:', err);
        console.log('\nVerifica:');
        console.log('1. El PLC está encendido y accesible en la red');
        console.log('2. El firewall permite el puerto 48898');
        console.log('3. El AMS Net ID del PLC es correcto');
        console.log('4. TwinCAT está en modo RUN (o usa rawClient/allowHalfOpen)');
        process.exit(1);
    }
}

// Manejar desconexiones
client.on('connectionLost', () => {
    console.log('⚠️  Conexión perdida. Intentando reconectar...');
});

client.on('disconnect', () => {
    console.log('ℹ️  Desconectado del PLC');
});

main();

---

Edita el archivo en el PLC: C:\TwinCAT\3.1\Target\StaticRoutes.xml --> TwinCAT 4024

C:\Program Files (x86)\Beckhoff\TwinCAT\3.1\Target\StaticRoutes.xml --> TwinCAT 4026

<RemoteConnections>
    <Route>
        <Name>Docker-Container</Name>
        <Address>192.168.0.10</Address>
        <NetId>192.168.0.10.1.1</NetId>
        <Type>TCP_IP</Type>
    </Route>
</RemoteConnections>

.env.docker

PLC_IP=192.168.0.102
PLC_AMS_NET_ID=192.168.0.102.1.1
LOCAL_AMS_NET_ID=192.168.0.10.1.1
LOCAL_ADS_PORT=32750
TARGET_ADS_PORT=851
ROUTER_TCP_PORT=48898

[jisotalo]

Thanks!