# Ned-red work as modbus tcp server communicate with scada application
**URL:** https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205
**Category:** General
**Tags:** modbus
**Created:** [5 June 2026 17:07 UTC](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205 "2026-06-05T17:07:09Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@Boy\_co\_don](https://discourse.nodered.org/u/Boy_co_don)
#### Post date: [5 June 2026 17:07 UTC](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205/1 "2026-06-05T17:07:09Z")
Dear Expert
I want to buid node-red as Modbus TCP server to communicate with SCADA.
I need Node-red Mobus TCP server send data to SCADA via FC4 and FC2. And receive command from SCADA with FC3/FC6 and FC1/FC5.
I tried do with Modbus server in contrib modbus tcp pạkage, it seem not support FC4 and FC2
DO anyone have solution
Many thank
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [5 June 2026 17:19 UTC](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205/2 "2026-06-05T17:19:34Z")
Can't the scada system do MQTT?
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [6 June 2026 17:52 UTC](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205/3 "2026-06-06T17:52:42Z")
> [@Boy\_co\_don](#):
>
> I need Node-red Mobus TCP server send data to SCADA via FC4 and FC2
> [@Boy\_co\_don](#):
>
> I tried do with Modbus server in contrib modbus tcp pạkage
To send data (FC2/FC4) to a SCADA is a client like node-red-contrib-modbus
A Server (Slave) sits passively, listening on a specific port (usually 502), waiting for the a Client (Master) to ask for data or command it to change a state.
---
### Author:  [@Boy\_co\_don](https://discourse.nodered.org/u/Boy_co_don)
#### Post date: [7 June 2026 10:40 UTC](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205/4 "2026-06-07T10:40:40Z")
Thank for your reply.
My scada application connected to Node-red via Modbus TCP OK.
I uses Function before input of Modbus Server block like Picture with code: msg.payload = { 'value': [10, 20, 30, 40, 50, 60, 70, 80, 90], 'register': 'input', 'address': 0, 'disableMsgOutput': 0 }; return msg;
With above Code, I can only transmit one Function code into Modbus Server block.
How can I transit multiple fuctioncode value into Modbus server block at the same time?
Many thank
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [7 June 2026 11:03 UTC](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205/5 "2026-06-07T11:03:32Z")
> [@Boy\_co\_don](#):
>
> I tried do with Modbus server in contrib modbus tcp pạkage, it seem not support FC4 and FC2
Looking at the readme for node-red-contrib-modbus it seems that the server function is being split out into node-red-contrib-modbus-flex-server, but since that has not been updated for a year I don't know whether it is working. You could try that.
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [7 June 2026 11:07 UTC](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205/6 "2026-06-07T11:07:10Z")
You did not answer my question asking whether the SCADA system can communicate using MQTT. That would be much easier than trying to simulate a modbus slave device in node-red.
---
### Author:  [@Boy\_co\_don](https://discourse.nodered.org/u/Boy_co_don)
#### Post date: [7 June 2026 11:25 UTC](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205/7 "2026-06-07T11:25:04Z")
Dear sir
Scada only use modbus or iec60870-5-104
---
### Author:  [@Boy\_co\_don](https://discourse.nodered.org/u/Boy_co_don)
#### Post date: [7 June 2026 11:26 UTC](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205/8 "2026-06-07T11:26:23Z")
Dear sir
Do you know other package can work as modbus tcp server?
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [7 June 2026 11:28 UTC](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205/9 "2026-06-07T11:28:28Z")
> [@Boy\_co\_don](#):
>
> Do you know other package can work as modbus tcp server
No, have you tried the other one I suggested?
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [5 September 2026 11:29 UTC](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205/10 "2026-09-05T11:29:13Z")
This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.