Communication between two fx30 modules via TCP/IP or MQTT or Modbus idk

Hello, I currently need to find a solution to make two sierra fx30 modules communicate with each other (TCP/IP or MQTT or Modbus) permanently in order to be able to report when one of the two stops responding (loss of connection, no longer on the network, etc).
The problem is that I have no idea how to do this as it is not in my area of expertise.
I have read a lot of documentation but all the solutions talk about serial port… My modules are in Ethernet and have no serial port!
How can I do it ? Thank you in advance for your help.

I can’t download other node. I have to use ONLY basic node…

Does this device run node-red?

Or does it have MQTT connectivity? (link please)

Or does it list modbus in its manuals? (link please)

Yes both modules run node-red, I already program on them and I already use Modbus for one of my flow.
I'll send you the documentation of the module in question.

Do you have an MQTT broker running on one of them or somewhere else on the network?

Mmmh, I think yes, I send you the technical manuel but is in french

Then it is very easy to pass values between them.

Do a simple test...


Add an mqtt in node
Subscribe to test topic
Connect that to a debug node


Connect on inject node to an mqtt out node, set the topic to test

Both units MQTT nodes should connect to the same broker.

Pressing the inject node on unit 2 should make the value appear on unit 1

I feel really stupid haha but how can I have the @ of the mqtt broker ??


If all you need to do is to check that they are connected and basically functioning you may be able to use Ping. Assuming they respond to ping that is.

You have to put the IP address of your broker in there. Where are you running the broker?

Yes I know that but I have to program a flow who can do that automatically with basic node. So I search a solution with MQTT but I know nothing of this protocol.

This will tell you everything you need to know about MQTT. MQTT Essentials - All Core Concepts explained

You can use Ping with basic nodes. node-red-node-ping.

I can't instal new nodes... Don't know why but my node-red don't have the manage palette :upside_down_face:

Can you run ping using an exec node?

I don't have an exec node either...
I've already looked into this and obviously it would be much easier that way

Looks like MQTT will be the easiest then, provided you have the MQTT nodes that is, and that you have somewhere to install the broker (probably Mosquitto).

I ask myself if it's possible to do a system of communication with SMS between two modules (they have SIM and phone number).
But if it's impossible yes I'll do this with MQTT.
Thanks for your advice :slight_smile:

Or you could just use http requests in each direction.

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