Dear Guys. I'm use Modbus Read node from default library Modbus to read data from modbus Server. The connection was established and work Ok. But there is a small problem. when Connection is normal, Modbus Read will return layload normally with array result. But if because some of reasons, the s…

In your Modbus read node try enabling the option "Empty msg on Modbus fail" [image] Its not going to do exactly what you need which is all elements to be zero .. but it should produce an empty msg .. which can give you an indication of a failed connection. That msg can then be manipulated to wha…

I tried your solution, but it l also do not work

Add a debug node after the modbus node and show us what it shows when the connection fails.

Hi Colin When Rad Modbus or Modbus Flex getter lost connection, no message was shoed via debug.

You said in your first post that it keeps sending the old data

If you want to take action when no data are received then use a Trigger node. Set it to Send Original Message, Then Wait For 10 seconds, then Send whatever message you need. Then if there is a gap of 10 seconds in the data stream it will send the message you have configured.

Also, if you just need to update a display to show no data then you can tell the Trigger node to send the timeout message to the second output and use that output to send an appropriate value to the displays.

[image] Dear Sir I used function node in front of Modbus Flext getter. I mean that, when lost connection with server, no output payload.

Use a Trigger node as I suggested.

Connect the Trigger node to the output of the modbus node, obviously.

Modbus Read Node via Modbus TCP in Node Red

General

Colin 28 June 2026 10:23 16

Select the nodes that you showed the image of earlier, plus the Trigger node, then hit CTRL+E and click Export to Clipboard.

Then paste the flow here. In order to make flow usable it is necessary to surround it with three backticks (also known as a left quote or backquote ```)

``` 
   code goes here 
```

See this post for more details - How to share code or flow json

Topic		Replies	Views
Modbus TCP loosing connection to clients, does not reconnect General modbus	20	2031	7 November 2022
Possibly a bug in contrib-modbus or even in node-red core General modbus	6	176	20 May 2026
Node-red-contrib-modbus. Cannot recover TCP connection after server rebooting General	6	1718	4 January 2022
Modbus Not Reconnecting Industrial	3	544	21 April 2021
Node-red-contrib-modbus stop execution in case of connection issue General	4	202	28 December 2023

Modbus Read Node via Modbus TCP in Node Red

Related topics