Dear all.  
I am having some problems configuring the MQTT network and would like to request specialized support:  
My hardware configuration is as follows:  PLC - S7-1200 - CPU 1214C DCDCDC (6ES7 214-1AG40-0XB0), version 4.6 The CPU's IP is 192.168.0.10. TIA V18. 
I will be communicating with some devices via MQTT using IP 143.8.167.27 and port 1883. However, since I am having problems with the block, I have chosen to use the MQTT Explorer software and set the IP range to 192.168.0.15 to ensure that it works.  
My first question is about the IP ranges. Is it possible for me to have the PLC in the 192.168.0.10 range and the connection device in the 143.8.167.27 range. Are both cables connected to a Siemens managed switch (Scalance)?  
I have completed the entire creation of the LMQTT_Cliente block and I believe that the DB will configure the block, but every time I activate the block enable, the status output remains at code 16#7002 for 5 seconds and after that time it changes to 16#8620.  
The following are the parameters that I configured:  
Enable = True; 
Subscribe = True; 
hwid = 0; connid = 2; 
broker = '192.168.0.15'; 
port = 1883; keepAlive = 10; 
clientidentifier = 'comunicacao'; 
mqtttopic = 'Broker'; 
receivetopic = 'Broker'; 
 
Thank you

Hi,

You're encountering a couple of issues here.

hwid

Your hwid is 0 if i remember it should be automatic but i never trust automatic selection, it could be better to make sure and define your profinet hwid.

MQTT

You are talking about devices but you never talked about the brocker, are you aware that MQTT communication can't be done without a brocker ? You talked about MQTT on the PLC, some “devices” and MQTT Explorer wich are all clients.

IP Range

Your PLC is on the 192.168.0.x subnet, while the device you are trying to reach (143.8.167.27) is in a completely different network (public IP). A switch even a managed Siemens Scalance one  cannot route traffic between different IP subnets.

To connect to 143.8.167.27, you would need a router or a Layer 3 device that can handle routing between your local 192.168.x.x network and the public or different subnet (143.8.x.x). 

Status Codes

• 16#7002 – "Follow-up call during active FB processing"
  This is normal and just indicates that the MQTT block is currently active and trying to establish a connection.
• 16#8620 – "Connection establishment timeout"
  This means the client (your PLC) is trying to connect to the broker but gets no response in time.

You might want to read this : https://support.industry.siemens.com/cs/de/en/view/109780503

Hello. It's been a big challenge.

hwid

Yes. I've tried both possible modes. Now I've adjusted it to hwid 64

MQTT

Yes. The Broker I use is Mosquitto to make the connection. It's working when I fill in the host with test.mosquitto.org. However, when I enter the IP that I'm going to test the system with, 192.168.0.15, it doesn't connect and gives me a timeout error. I'm not using a username or password.

IP Range

This IP (143.8.167.27) would be configured in the future. But thank you for the observation regarding traffic between subnets. I'll analyze this issue carefully.

Status Codes

Yes. The statuses are very clear. However, I can't stabilize the connection with the Mosquitto Broker when I direct the host to the IP 192.168.0.15

Thank You.

Hi again,

Just to eliminate all ambiguity and pinpoint the issue, I’d like to confirm the following three specific tests:

MQTT Explorer → 192.168.0.15:
Does MQTT Explorer successfully connect to the Mosquitto broker running at this IP?

PLC → test.mosquitto.org:
You mentioned this worked just confirming, the PLC connects successfully to the public Mosquitto broker?

PLC → 192.168.0.15:
This is the one currently failing.

Hi again,

Just to eliminate all ambiguity and pinpoint the issue, I’d like to confirm the following three specific tests:

Ok.

MQTT Explorer → 192.168.0.15:
Does MQTT Explorer successfully connect to the Mosquitto broker running at this IP?

No.

PLC → test.mosquitto.org:
You mentioned this worked just confirming, the PLC connects successfully to the public Mosquitto broker?

Yes.

PLC → 192.168.0.15:
This is the one currently failing.

Yes.

Additional Information is that the connection test ( ping ) also does not work with the IP 192.168.0.15. configured in MQTT block.

I'm creating a new software and I'll leave te only MQTT block in for testing.