# \#modbus

**URL:** https://discourse.nodered.org/tag/modbus/13.md

[Latest](https://discourse.nodered.org/latest.md) · [Categories](https://discourse.nodered.org/categories.md) · [Tags](https://discourse.nodered.org/tags.md)

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## [Modbus server Address assigning issue](https://discourse.nodered.org/t/modbus-server-address-assigning-issue/101478)

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**Author:** [@aminulhaq](https://discourse.nodered.org/u/aminulhaq)\
**Replies:** 1\
**Last updated:** [13 August 2026 12:15 UTC](https://discourse.nodered.org/t/modbus-server-address-assigning-issue/101478 "2026-08-13T12:15:38Z")

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Hi i am using node-red-contrib-modbus 5.4 and use modbus server and wientek tk8071ip hmi as modbus tcp/ip the connection is happend perfectly i have set holding register at numeric display on hmi with address 4x01 to 4x0…

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## [Building the tool I wish existed – SCADA-System in Node-RED](https://discourse.nodered.org/t/building-the-tool-i-wish-existed-scada-system-in-node-red/100545)

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**Author:** [@reflink](https://discourse.nodered.org/u/reflink)\
**Replies:** 4\
**Last updated:** [2 August 2026 11:03 UTC](https://discourse.nodered.org/t/building-the-tool-i-wish-existed-scada-system-in-node-red/100545 "2026-08-02T11:03:46Z")

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Hi everyone, I work as a refrigeration technician in Sweden, and for the last 3 to 4 months I’ve been building my own SCADA-style system with Node-RED. The reason is simple: most existing products are far too expensive…

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## [Modbus Read Node via Modbus TCP in Node Red](https://discourse.nodered.org/t/modbus-read-node-via-modbus-tcp-in-node-red/101365)

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**Author:** [@Boy\_co\_don](https://discourse.nodered.org/u/Boy_co_don)\
**Replies:** 15\
**Last updated:** [28 June 2026 10:23 UTC](https://discourse.nodered.org/t/modbus-read-node-via-modbus-tcp-in-node-red/101365 "2026-06-28T10:23:41Z")

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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 r…

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## [Modbus TCP connection to node red replying with errors](https://discourse.nodered.org/t/modbus-tcp-connection-to-node-red-replying-with-errors/101241)

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**Author:** [@joeltackie](https://discourse.nodered.org/u/joeltackie)\
**Replies:** 1\
**Last updated:** [11 June 2026 21:16 UTC](https://discourse.nodered.org/t/modbus-tcp-connection-to-node-red-replying-with-errors/101241 "2026-06-11T21:16:38Z")

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I am to connect node-red to a modbus server on the same network (LAN) Using node-red-contrib-modbus palette I keep getting this error; As shown in image 1 {"enc":true,"type":"error","data":{"name":"Error","message":"P…

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## [Ned-red work as modbus tcp server communicate with scada application](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205)

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**Author:** [@Boy\_co\_don](https://discourse.nodered.org/u/Boy_co_don)\
**Replies:** 8\
**Last updated:** [7 June 2026 11:28 UTC](https://discourse.nodered.org/t/ned-red-work-as-modbus-tcp-server-communicate-with-scada-application/101205 "2026-06-07T11:28:28Z")

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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…

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## [Modbus RTU transparent proxy](https://discourse.nodered.org/t/modbus-rtu-transparent-proxy/101147)

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**Author:** [@RobStockley](https://discourse.nodered.org/u/RobStockley)\
**Replies:** 3\
**Last updated:** [30 May 2026 00:14 UTC](https://discourse.nodered.org/t/modbus-rtu-transparent-proxy/101147 "2026-05-30T00:14:19Z")

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Does anyone here have an example, or can put me in touch with someone, with a working example of Modbus RTU transparent proxy using RPi and Node-Red? I'd like to monitor RS485 metering data. Increased latency will not be…

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## [Modbus value display problem](https://discourse.nodered.org/t/modbus-value-display-problem/101117)

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**Author:** [@jlt57](https://discourse.nodered.org/u/jlt57)\
**Replies:** 3\
**Last updated:** [25 May 2026 08:59 UTC](https://discourse.nodered.org/t/modbus-value-display-problem/101117 "2026-05-25T08:59:25Z")

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Hello everyone, I'm having a problem with Modbus and data display. (I'm a beginner, but I think I understand the basics of Node-RED.) When I send a query of several words to a PLC, the data arrives correctly (in an ar…

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## [Struggling with Modbus RTU timing over TCP](https://discourse.nodered.org/t/struggling-with-modbus-rtu-timing-over-tcp/101084)

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**Author:** [@Christopher.Scott](https://discourse.nodered.org/u/Christopher.Scott)\
**Replies:** 1\
**Last updated:** [21 May 2026 10:12 UTC](https://discourse.nodered.org/t/struggling-with-modbus-rtu-timing-over-tcp/101084 "2026-05-21T10:12:29Z")

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I'm trying to integrate a IoT-SS101 with my Node-RED setup. Does anyone have the correct JSON flow for handling the polling interval? Here is the device manual: https://valtoris.com/wp-content/uploads/2025/11/1CH-RS232-4…

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## [Possibly a bug in contrib-modbus or even in node-red core](https://discourse.nodered.org/t/possibly-a-bug-in-contrib-modbus-or-even-in-node-red-core/100877)

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**Author:** [@Roman\_P](https://discourse.nodered.org/u/Roman_P)\
**Replies:** 6\
**Last updated:** [20 May 2026 14:32 UTC](https://discourse.nodered.org/t/possibly-a-bug-in-contrib-modbus-or-even-in-node-red-core/100877 "2026-05-20T14:32:58Z")

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Hi! I need to sequentially poll several Modbus IDs connected to the same serial-to-TCP gateway. Because this gateway is a bit buggy and sometimes fail to manage poll queue (TCP to RS-485) in a propper manner, I'm forced…

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## [Trying to figure out modbus](https://discourse.nodered.org/t/trying-to-figure-out-modbus/100915)

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**Author:** [@txrocks](https://discourse.nodered.org/u/txrocks)\
**Replies:** 11\
**Last updated:** [20 May 2026 00:47 UTC](https://discourse.nodered.org/t/trying-to-figure-out-modbus/100915 "2026-05-20T00:47:22Z")

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I am trying to figure out how to move forward from where I am at. I can get the modbus registers when I click timestamp. I can not tell exactly which ones are which, these ones should all be read. Other modbus setups …

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## [Modbus server - strange debug mesage](https://discourse.nodered.org/t/modbus-server-strange-debug-mesage/101031)

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**Author:** [@juntiedt](https://discourse.nodered.org/u/juntiedt)\
**Replies:** 1\
**Last updated:** [15 May 2026 09:06 UTC](https://discourse.nodered.org/t/modbus-server-strange-debug-mesage/101031 "2026-05-15T09:06:11Z")

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As you can see on the picture, my proxy server for solar inverters works but I continously get this error mesage: "Is Not A Valid Memory Write Message To Server" Any idea how to get rid of it?

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## [Which node is the best suit if I am using ZLAN5407-M to transmit the data from power meter?](https://discourse.nodered.org/t/which-node-is-the-best-suit-if-i-am-using-zlan5407-m-to-transmit-the-data-from-power-meter/101013)

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**Author:** [@Champion](https://discourse.nodered.org/u/Champion)\
**Replies:** 0\
**Last updated:** [14 May 2026 03:16 UTC](https://discourse.nodered.org/t/which-node-is-the-best-suit-if-i-am-using-zlan5407-m-to-transmit-the-data-from-power-meter/101013 "2026-05-14T03:16:39Z")

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Currently I am using ZLAN (RS485 to Ethernet adapter) to transmit the data from the power meter to node red, I would like to know the which node to use to receive the data in NodeRed. Should I use Modbus Getter Node or …

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## [ENRON Modbus Server node for Node-RED](https://discourse.nodered.org/t/enron-modbus-server-node-for-node-red/101005)

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**Author:** [@RobAxt](https://discourse.nodered.org/u/RobAxt)\
**Replies:** 0\
**Last updated:** [13 May 2026 14:37 UTC](https://discourse.nodered.org/t/enron-modbus-server-node-for-node-red/101005 "2026-05-13T14:37:32Z")

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Hi everyone, While working on a project that required ENRON Modbus support, I looked for an existing Node-RED node that could act as an ENRON Modbus server, but I could not find one that matched what I needed. So I cre…

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## [Hi everyone,  I’m working on a Node-RED flow where I need to read the same parameter from multiple Modbus slaves (Slave IDs 1 to 100)](https://discourse.nodered.org/t/hi-everyone-i-m-working-on-a-node-red-flow-where-i-need-to-read-the-same-parameter-from-multiple-modbus-slaves-slave-ids-1-to-100/100634)

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**Author:** [@adarshi](https://discourse.nodered.org/u/adarshi)\
**Replies:** 6\
**Last updated:** [24 March 2026 17:06 UTC](https://discourse.nodered.org/t/hi-everyone-i-m-working-on-a-node-red-flow-where-i-need-to-read-the-same-parameter-from-multiple-modbus-slaves-slave-ids-1-to-100/100634 "2026-03-24T17:06:26Z")

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Requirements: Read the same register/parameter from each slave (IDs 1 → 100) Optimize the flow for low CPU utilization Ensure efficient polling (avoid unnecessary load or blocking) Insert/store each slave’s data into an…

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## [How to get data from the F8926-GW Indoor Gateway by using Node Red?](https://discourse.nodered.org/t/how-to-get-data-from-the-f8926-gw-indoor-gateway-by-using-node-red/100602)

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**Author:** [@Champion](https://discourse.nodered.org/u/Champion)\
**Replies:** 10\
**Last updated:** [23 March 2026 02:37 UTC](https://discourse.nodered.org/t/how-to-get-data-from-the-f8926-gw-indoor-gateway-by-using-node-red/100602 "2026-03-23T02:37:49Z")

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I am connecting the F8926-GW to a IPC, I would like to ask is here anyone know how to use Node Red to get data from F8926-GW?

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## [NodeRed Dashboard and Modbus control delay / problems](https://discourse.nodered.org/t/nodered-dashboard-and-modbus-control-delay-problems/99977)

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**Author:** [@Daks](https://discourse.nodered.org/u/Daks)\
**Replies:** 1\
**Last updated:** [18 December 2025 11:04 UTC](https://discourse.nodered.org/t/nodered-dashboard-and-modbus-control-delay-problems/99977 "2025-12-18T11:04:27Z")

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Hey all, Currently im working on a project with SMA inverters (uses Sunspec registers), where im building a node-red enviornment to read and control. Below is my SMA inverter configuration along with what the dashboard…

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## [Modbus multi reading based on DB table of IP addresses](https://discourse.nodered.org/t/modbus-multi-reading-based-on-db-table-of-ip-addresses/99845)

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**Author:** [@Felix](https://discourse.nodered.org/u/Felix)\
**Replies:** 0\
**Last updated:** [2 December 2025 16:44 UTC](https://discourse.nodered.org/t/modbus-multi-reading-based-on-db-table-of-ip-addresses/99845 "2025-12-02T16:44:48Z")

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Hi all, do you have any knowledge, how to read from modbus TCP devices, based on DB table?? I have an example, which I have accumulated it by scripts from the web. Some things I have changed, but I think that is not cor…

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## [Modbus TCP failed / Proxmox LXC](https://discourse.nodered.org/t/modbus-tcp-failed-proxmox-lxc/99567)

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**Author:** [@monardfr](https://discourse.nodered.org/u/monardfr)\
**Replies:** 5\
**Last updated:** [3 November 2025 13:31 UTC](https://discourse.nodered.org/t/modbus-tcp-failed-proxmox-lxc/99567 "2025-11-03T13:31:51Z")

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Hi, I get the following error when trying to retrieve PT100 probe values via Modbus TCP (using modbus contrib). Client -\> fsm failed state after sending Get More About It By Logging TCP@192.168.1.201:8887 default Unit…

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## [Data length error, expected x got y (x \> y)](https://discourse.nodered.org/t/data-length-error-expected-x-got-y-x-y/99153)

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**Author:** [@BairDev](https://discourse.nodered.org/u/BairDev)\
**Replies:** 2\
**Last updated:** [25 September 2025 07:26 UTC](https://discourse.nodered.org/t/data-length-error-expected-x-got-y-x-y/99153 "2025-09-25T07:26:42Z")

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We can communicate with a device at /dev/ttyAMA0. It uses ModBus RTU, 9600 baud rate. But when I try to read data according to the documentation of the device I am getting the error: "Data length error, expected 7 got…

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## [Problems with node-red-contrib-modbus 5.43.0 after upgrading to Node-Red 4.1.0](https://discourse.nodered.org/t/problems-with-node-red-contrib-modbus-5-43-0-after-upgrading-to-node-red-4-1-0/98709)

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**Author:** [@ftaddia](https://discourse.nodered.org/u/ftaddia)\
**Replies:** 1\
**Last updated:** [21 August 2025 12:14 UTC](https://discourse.nodered.org/t/problems-with-node-red-contrib-modbus-5-43-0-after-upgrading-to-node-red-4-1-0/98709 "2025-08-21T12:14:48Z")

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Node-Red version: 4.1.0 NodeJS version: 22.18.0 Hi, I'm also asking here in the forum to see if I'm the only one having this problem or if there are other people. This is the issue I've already opened in the node-spec…

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## [Modbus to mySQL flow suggestions](https://discourse.nodered.org/t/modbus-to-mysql-flow-suggestions/98531)

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**Author:** [@BambosD](https://discourse.nodered.org/u/BambosD)\
**Replies:** 27\
**Last updated:** [7 August 2025 06:33 UTC](https://discourse.nodered.org/t/modbus-to-mysql-flow-suggestions/98531 "2025-08-07T06:33:40Z")

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Hello everyone, i’m trying to log some values from modbus devices to the mySQL node. the flow is not very clear to me as functionality and setup, so i’m posting here what i’m trying to do and asking how is possible to a…

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## [How to access a Modbus TCP Device](https://discourse.nodered.org/t/how-to-access-a-modbus-tcp-device/98147)

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**Author:** [@Janvi](https://discourse.nodered.org/u/Janvi)\
**Replies:** 11\
**Last updated:** [23 July 2025 05:53 UTC](https://discourse.nodered.org/t/how-to-access-a-modbus-tcp-device/98147 "2025-07-23T05:53:43Z")

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Like to read the apparent power from my Ziehl EFR4001 device for visualisation in my dashboard. The device is in my local network accessible by http where I enable the Modbus TCP setup using Port 502. For NodeRed I i…

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## [Modbus data aggregation for plotting](https://discourse.nodered.org/t/modbus-data-aggregation-for-plotting/97803)

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**Author:** [@Sido1](https://discourse.nodered.org/u/Sido1)\
**Replies:** 21\
**Last updated:** [4 July 2025 12:09 UTC](https://discourse.nodered.org/t/modbus-data-aggregation-for-plotting/97803 "2025-07-04T12:09:39Z")

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Hi everyone, I'm currently working with Node-RED to build a dashboard. I have three Modbus requests that return energy data from different sources (here transformed to functions). My goal is to create a line or bar char…

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## [Modbus flex-server ECONNREFUSE](https://discourse.nodered.org/t/modbus-flex-server-econnrefuse/96721)

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**Author:** [@stgj](https://discourse.nodered.org/u/stgj)\
**Replies:** 14\
**Last updated:** [19 June 2025 04:26 UTC](https://discourse.nodered.org/t/modbus-flex-server-econnrefuse/96721 "2025-06-19T04:26:47Z")

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I have a server with a modbus-contrib-flex-getter that reads from another server Modbus-contrib-flex-server. Regularly (once or twice a day, cant see a pattern to it) I get an error "ECONNREFUSED" from the server that h…

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## [Insert a float value in modbus contrib flex-servers buffer problems](https://discourse.nodered.org/t/insert-a-float-value-in-modbus-contrib-flex-servers-buffer-problems/97158)

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**Author:** [@stgj](https://discourse.nodered.org/u/stgj)\
**Replies:** 0\
**Last updated:** [20 May 2025 09:01 UTC](https://discourse.nodered.org/t/insert-a-float-value-in-modbus-contrib-flex-servers-buffer-problems/97158 "2025-05-20T09:01:14Z")

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Hi. I have some issues I don't understand with inserting float data in to the modbus flex-servers buffer and read that data with a modbus flex-getter when that data is in little endian. First an example that I'm able t…

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## [How can I configure a Modbus TCP client node in Node-RED to listen for incoming connections? Once the connection is established, I would like the client to start polling data](https://discourse.nodered.org/t/how-can-i-configure-a-modbus-tcp-client-node-in-node-red-to-listen-for-incoming-connections-once-the-connection-is-established-i-would-like-the-client-to-start-polling-data/94402)

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**Author:** [@kpkpkalpesh](https://discourse.nodered.org/u/kpkpkalpesh)\
**Replies:** 7\
**Last updated:** [5 March 2025 08:48 UTC](https://discourse.nodered.org/t/how-can-i-configure-a-modbus-tcp-client-node-in-node-red-to-listen-for-incoming-connections-once-the-connection-is-established-i-would-like-the-client-to-start-polling-data/94402 "2025-03-05T08:48:22Z")

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I want the node red Modbus client to listen on port . Once my Modbus device is powered up, it should automatically connect to the node red Modbus client using the node red IP address and the port. After the device is con…

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## [Modbus Server/Slave IO mapping](https://discourse.nodered.org/t/modbus-server-slave-io-mapping/95541)

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**Author:** [@jper25](https://discourse.nodered.org/u/jper25)\
**Replies:** 8\
**Last updated:** [21 February 2025 14:30 UTC](https://discourse.nodered.org/t/modbus-server-slave-io-mapping/95541 "2025-02-21T14:30:43Z")

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Hello, How would I turn my application into a slave? I can do everything but update discrete inputs on my server so an external Client/Master can read them. I know there is an IO config node for the reading/getter nod…

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## [Help with Modbus write](https://discourse.nodered.org/t/help-with-modbus-write/95331)

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**Author:** [@grant1](https://discourse.nodered.org/u/grant1)\
**Replies:** 2\
**Last updated:** [12 February 2025 01:25 UTC](https://discourse.nodered.org/t/help-with-modbus-write/95331 "2025-02-12T01:25:16Z")

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Greetings. I can retrieve via FC 4: Read Input Registers the Actual and Setpoint values from my Modbus RTU enabled temperature controller. Now I want to try to write the setpoint using FC 6. Both flows are attached. …

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## [Running Node-RED 24/7/365](https://discourse.nodered.org/t/running-node-red-24-7-365/95121)

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**Author:** [@nago93](https://discourse.nodered.org/u/nago93)\
**Replies:** 4\
**Last updated:** [5 February 2025 04:24 UTC](https://discourse.nodered.org/t/running-node-red-24-7-365/95121 "2025-02-05T04:24:51Z")

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Hi, Im conceptualizing a controller, to manage a industrial battery, in order to dispatch it in high peak demand depending of the solar generation. This is an aplication that should be running 24/7/365, All the communic…

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## [Modbus values goes zero after change and deploy](https://discourse.nodered.org/t/modbus-values-goes-zero-after-change-and-deploy/95055)

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**Author:** [@BambosD](https://discourse.nodered.org/u/BambosD)\
**Replies:** 5\
**Last updated:** [2 February 2025 11:32 UTC](https://discourse.nodered.org/t/modbus-values-goes-zero-after-change-and-deploy/95055 "2025-02-02T11:32:47Z")

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Hello everyone, I'm new to node-red and i want to use it for modbus values / store / preview / dashboard. there is a strange behavior and i don't know if i'm missing something or is some kind of bug. as you can see he…

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