# \#node-red-node-serialport

**URL:** https://discourse.nodered.org/tag/node-red-node-serialport/102.md

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## [Node-red communication with NOLEK S9 via RS232](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418)

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**Author:** [@AlastairLong](https://discourse.nodered.org/u/AlastairLong)\
**Replies:** 33\
**Last updated:** [9 July 2026 15:12 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418 "2026-07-09T15:12:01Z")

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I am trying to read leak test data from a NOLEK S9 unit but i cannot appear to get this setup correctly. I am using a serial node with the following Baud rate: 9600 Data bits: 8 Stop bits: 2 Parity: None Flow: none …

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## [Reading 3x RS232 legacy machines via a single Gateway to Node-RED](https://discourse.nodered.org/t/reading-3x-rs232-legacy-machines-via-a-single-gateway-to-node-red/100740)

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**Author:** [@DiogoI4.0](https://discourse.nodered.org/u/DiogoI4.0)\
**Replies:** 13\
**Last updated:** [15 May 2026 12:34 UTC](https://discourse.nodered.org/t/reading-3x-rs232-legacy-machines-via-a-single-gateway-to-node-red/100740 "2026-05-15T12:34:15Z")

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Hello everyone, I need to collect data from plastic injection molding machines and I'm facing the following problem. The scenario: We have a production line with 3 independent machines. They are controlled by Techmation…

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## [Search for examples for serial request node usage (/dev/ttyUSB0)](https://discourse.nodered.org/t/search-for-examples-for-serial-request-node-usage-dev-ttyusb0/100028)

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**Author:** [@nosered1966](https://discourse.nodered.org/u/nosered1966)\
**Replies:** 21\
**Last updated:** [11 January 2026 21:34 UTC](https://discourse.nodered.org/t/search-for-examples-for-serial-request-node-usage-dev-ttyusb0/100028 "2026-01-11T21:34:12Z")

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Hello everyone, I hope you all had a wonderful Christmas! I am looking for help with the following ‘problem’: My gas heating is connected to my Rpi4B (USB Interface) and I can read data using the following Python scri…

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## [NodeRed serial ports keep disconnecting](https://discourse.nodered.org/t/nodered-serial-ports-keep-disconnecting/99402)

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**Author:** [@Kepler7894i](https://discourse.nodered.org/u/Kepler7894i)\
**Replies:** 5\
**Last updated:** [19 October 2025 21:04 UTC](https://discourse.nodered.org/t/nodered-serial-ports-keep-disconnecting/99402 "2025-10-19T21:04:19Z")

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Hi there. I am having issues with serial connections in NodeRed. I am using the 'node-red-node-serialport' node to connect a Raspberry Pi 5b to various serial USB devices controlled by PIC24's. This works fine, but if I…

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## [NodeRed receives no value when one is returned by serial request](https://discourse.nodered.org/t/nodered-receives-no-value-when-one-is-returned-by-serial-request/99324)

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**Author:** [@Kepler7894i](https://discourse.nodered.org/u/Kepler7894i)\
**Replies:** 4\
**Last updated:** [9 October 2025 14:57 UTC](https://discourse.nodered.org/t/nodered-receives-no-value-when-one-is-returned-by-serial-request/99324 "2025-10-09T14:57:03Z")

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I have a PIC24 connected to a sensor that is programmed with a custom driver to send data when a '?\\r' is sent as a request "0x3F0D". I've confirmed NodeRed is connected to the right serial port and that data is sending…

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## [Same Serial flow on Pi400 and windows different results](https://discourse.nodered.org/t/same-serial-flow-on-pi400-and-windows-different-results/98857)

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**Author:** [@vikingsraven](https://discourse.nodered.org/u/vikingsraven)\
**Replies:** 1\
**Last updated:** [27 August 2025 14:43 UTC](https://discourse.nodered.org/t/same-serial-flow-on-pi400-and-windows-different-results/98857 "2025-08-27T14:43:04Z")

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HI , so i have a small lidar unit , old one Baudrate 230400 , so im trying to get some data from it, to get it ti start you send the letter b, to stop the letter e. I’m using the same flow on windows as well as the pi40…

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## [MQTT topics creates loop with Serial Port](https://discourse.nodered.org/t/mqtt-topics-creates-loop-with-serial-port/96914)

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**Author:** [@WannabeMaker](https://discourse.nodered.org/u/WannabeMaker)\
**Replies:** 1\
**Last updated:** [5 May 2025 22:26 UTC](https://discourse.nodered.org/t/mqtt-topics-creates-loop-with-serial-port/96914 "2025-05-05T22:26:00Z")

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Hello, I have question regarding how to deal with MQTT topics. I have the following flow that I use to control a sensirion MFC5500. The flow works well without bug. The one problem that I have is when I want to do r…

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## [Weird serial issues](https://discourse.nodered.org/t/weird-serial-issues/96859)

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**Author:** [@ReonMonterus](https://discourse.nodered.org/u/ReonMonterus)\
**Replies:** 1\
**Last updated:** [4 May 2025 20:56 UTC](https://discourse.nodered.org/t/weird-serial-issues/96859 "2025-05-04T20:56:57Z")

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Hello! I am pretty new to Node-RED and I am working on a project that involves a bit of serial communication between a RPi 3B and several ESP32 devices over USB. The ESP32's are connected to things like relays and when s…

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## [Restart Node-Red to reset tcp in node connection](https://discourse.nodered.org/t/restart-node-red-to-reset-tcp-in-node-connection/94701)

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**Author:** [@gallionjason](https://discourse.nodered.org/u/gallionjason)\
**Replies:** 4\
**Last updated:** [17 January 2025 21:41 UTC](https://discourse.nodered.org/t/restart-node-red-to-reset-tcp-in-node-connection/94701 "2025-01-17T21:41:55Z")

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Hello I'm working on a prototype project and I have a sensor sending data to Node-Red through a tcp connection. Sometimes I lose connection to the device and cant receive data. The easy thing to do that works is just t…

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## [Node-red-serial port port selection](https://discourse.nodered.org/t/node-red-serial-port-port-selection/93845)

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**Author:** [@plouc](https://discourse.nodered.org/u/plouc)\
**Replies:** 6\
**Last updated:** [16 December 2024 14:27 UTC](https://discourse.nodered.org/t/node-red-serial-port-port-selection/93845 "2024-12-16T14:27:04Z")

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Hi there! I'm looking for a way a user with only access to node-red dashboard to be able to select which serial port to connect to. This topic is exactly talking about it: However the githubs links seems to be broken…

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## [Wireless M-Bus USB dongle problem](https://discourse.nodered.org/t/wireless-m-bus-usb-dongle-problem/89987)

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**Author:** [@werneroostendorp](https://discourse.nodered.org/u/werneroostendorp)\
**Replies:** 2\
**Last updated:** [25 November 2024 15:17 UTC](https://discourse.nodered.org/t/wireless-m-bus-usb-dongle-problem/89987 "2024-11-25T15:17:09Z")

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I have connected an IMST PA-iM871A Wireless M-Bus dongle to my PC (Windows). I have installed the drivers correctly because the provided software recognizes the USB stick. Now, I want to connect to an M-Bus device (a ga…

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## [Reading data from an ultrasonic sensor](https://discourse.nodered.org/t/reading-data-from-an-ultrasonic-sensor/92543)

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**Author:** [@slaaww](https://discourse.nodered.org/u/slaaww)\
**Replies:** 5\
**Last updated:** [21 October 2024 14:06 UTC](https://discourse.nodered.org/t/reading-data-from-an-ultrasonic-sensor/92543 "2024-10-21T14:06:54Z")

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Hello, I have an ultrasonic sensor MB7389 and I can't get the sensor values ​​on node-red. But I can see them on the raspberry pi by minicom. However, I selected the right parameters in the serialport node.

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## [ACCESS DENIED when using serialport in node-red](https://discourse.nodered.org/t/access-denied-when-using-serialport-in-node-red/89496)

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**Author:** [@xty19](https://discourse.nodered.org/u/xty19)\
**Replies:** 2\
**Last updated:** [15 July 2024 13:37 UTC](https://discourse.nodered.org/t/access-denied-when-using-serialport-in-node-red/89496 "2024-07-15T13:37:10Z")

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SerialPort Version 12.0.0 Node Version V18.16.1 (MACOS) V20.15.0(WIN10,WIN11 ) Electron Version No response Platform MACOS12.1 WIN11 WIN10 Architecture x64 Hardware or chipset of serialport FT232R USB UART I …

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## [Node-red on Pi not showing the Serial USBs](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945)

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**Author:** [@Hayder](https://discourse.nodered.org/u/Hayder)\
**Replies:** 10\
**Last updated:** [11 July 2024 21:39 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945 "2024-07-11T21:39:07Z")

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Hello; I am new to raspi, and I have a problem getting data from my Arduino board, which is connected via USB to the Pi. I used to connect the Arduino to a Nod-red installed on a PC, and it works very well. I have got t…

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## [It possible to configure the Node-RED node "node-red-node-serialport" with \`msg.port\` to dynamically change the port?](https://discourse.nodered.org/t/it-possible-to-configure-the-node-red-node-node-red-node-serialport-with-msg-port-to-dynamically-change-the-port/88816)

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**Author:** [@khalil\_khalil](https://discourse.nodered.org/u/khalil_khalil)\
**Replies:** 5\
**Last updated:** [21 June 2024 07:39 UTC](https://discourse.nodered.org/t/it-possible-to-configure-the-node-red-node-node-red-node-serialport-with-msg-port-to-dynamically-change-the-port/88816 "2024-06-21T07:39:35Z")

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Hello, I have a question: Is it possible to configure the Node-RED node "node-red-node-serialport" with msg.port to dynamically change the port? For example, when I send msg.port=COM1, the serialrequest node changes to …

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## [Issue with node-red-node-serialport and serial control Node: "TypeError: newline.substr is not a function" when Using Fixed Length Split Configuration](https://discourse.nodered.org/t/issue-with-node-red-node-serialport-and-serial-control-node-typeerror-newline-substr-is-not-a-function-when-using-fixed-length-split-configuration/88601)

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**Author:** [@khalil\_khalil](https://discourse.nodered.org/u/khalil_khalil)\
**Replies:** 1\
**Last updated:** [10 June 2024 22:08 UTC](https://discourse.nodered.org/t/issue-with-node-red-node-serialport-and-serial-control-node-typeerror-newline-substr-is-not-a-function-when-using-fixed-length-split-configuration/88601 "2024-06-10T22:08:47Z")

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Hello, I encountered an error with the node-red-node-serialport module while using the serial control node to open and close communication with a product. Here is my configuration and the steps I followed: Initial Conf…

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## [Issues with node-red-node-serialport Module](https://discourse.nodered.org/t/issues-with-node-red-node-serialport-module/88455)

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**Author:** [@khalil\_khalil](https://discourse.nodered.org/u/khalil_khalil)\
**Replies:** 12\
**Last updated:** [3 June 2024 12:56 UTC](https://discourse.nodered.org/t/issues-with-node-red-node-serialport-module/88455 "2024-06-03T12:56:45Z")

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Hello, I have encountered issues while using the node-red-node-serialport v2.0.2 (latest version). Here are the configuration parameters for the "serial request" node: msg.timeout is the timeout (in ms) after which th…

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## [How do I configure a flow to give me a prompt, whenever the Serial port is disconnected?](https://discourse.nodered.org/t/how-do-i-configure-a-flow-to-give-me-a-prompt-whenever-the-serial-port-is-disconnected/87726)

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**Author:** [@samyak5](https://discourse.nodered.org/u/samyak5)\
**Replies:** 8\
**Last updated:** [5 May 2024 19:55 UTC](https://discourse.nodered.org/t/how-do-i-configure-a-flow-to-give-me-a-prompt-whenever-the-serial-port-is-disconnected/87726 "2024-05-05T19:55:41Z")

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I'm trying to make a flow that reads data from an arduino's COM port, and then log it to a file and display it on my dashboard. I also want a notification to popup when the device is disconnected, or a serial-related err…

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## [Serial connection to CAS PD-II Scale](https://discourse.nodered.org/t/serial-connection-to-cas-pd-ii-scale/86976)

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**Author:** [@grodgers](https://discourse.nodered.org/u/grodgers)\
**Replies:** 12\
**Last updated:** [4 April 2024 16:35 UTC](https://discourse.nodered.org/t/serial-connection-to-cas-pd-ii-scale/86976 "2024-04-04T16:35:10Z")

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Hello awesome Node-RED community, I'm looking for general guidance here because I realize every serial device will be slightly different. I'm just not sure if I'm in the correct ballpark in my approach. My environment/…

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## [Serial in and out not working](https://discourse.nodered.org/t/serial-in-and-out-not-working/85489)

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**Author:** [@Tnnn](https://discourse.nodered.org/u/Tnnn)\
**Replies:** 4\
**Last updated:** [14 February 2024 10:41 UTC](https://discourse.nodered.org/t/serial-in-and-out-not-working/85489 "2024-02-14T10:41:13Z")

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Hi, I have a project where i'm using multiple barode readers. They are connected to a Raspberry pi 4 on bookworm version. Node-RED version: v3.1.5 Node.js version: v18.19.0. Now when using the flow 'serial request' i ca…

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## [Serial nodes can be deactivated if not used in a given configuration](https://discourse.nodered.org/t/serial-nodes-can-be-deactivated-if-not-used-in-a-given-configuration/85315)

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**Author:** [@Jean-Luc](https://discourse.nodered.org/u/Jean-Luc)\
**Replies:** 9\
**Last updated:** [8 February 2024 11:15 UTC](https://discourse.nodered.org/t/serial-nodes-can-be-deactivated-if-not-used-in-a-given-configuration/85315 "2024-02-08T11:15:15Z")

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Hello everyone. I have several serial nodes in my flow. Depending on the user's hardware configuration, not all of them are used. I would like to be able to deactivate them, but I understand that NR loads them as soon a…

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## [Trouble with serialport. Error code 31](https://discourse.nodered.org/t/trouble-with-serialport-error-code-31/84784)

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**Author:** [@nightmareside15](https://discourse.nodered.org/u/nightmareside15)\
**Replies:** 2\
**Last updated:** [22 January 2024 07:49 UTC](https://discourse.nodered.org/t/trouble-with-serialport-error-code-31/84784 "2024-01-22T07:49:21Z")

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Hello. I'm having trouble to use serialport in node red to connect with my GPT-9803. The connect I was using is rs232C ( using usb to rs232C with CH340 CHIP). I'm successfully connect it via tera-term and getting feedbac…

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## [Failed serial connection to Arduino: No such file or directory error](https://discourse.nodered.org/t/failed-serial-connection-to-arduino-no-such-file-or-directory-error/83970)

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**Author:** [@amooro\_123](https://discourse.nodered.org/u/amooro_123)\
**Replies:** 13\
**Last updated:** [23 December 2023 16:16 UTC](https://discourse.nodered.org/t/failed-serial-connection-to-arduino-no-such-file-or-directory-error/83970 "2023-12-23T16:16:25Z")

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I cannot get the serial node to connect to my Arduino Uno on a Zimaboard running Debian 11. Node-red v3.1.3 node.js v16.20.2 This is the error message I get in the debug window when I deploy: "\[serialconfig:0f4961208…

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## [Serialport input options when multiple characters define the beginning and end of a message](https://discourse.nodered.org/t/serialport-input-options-when-multiple-characters-define-the-beginning-and-end-of-a-message/83474)

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**Author:** [@intmech](https://discourse.nodered.org/u/intmech)\
**Replies:** 15\
**Last updated:** [15 December 2023 06:23 UTC](https://discourse.nodered.org/t/serialport-input-options-when-multiple-characters-define-the-beginning-and-end-of-a-message/83474 "2023-12-15T06:23:10Z")

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I would like to have the Serial In node break up messages or merge messages so that each message ends with three hex bytes (0x10, 0x04, 0x\*\*) the last one being a wildcard byte. I would also like to have each message be…

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## [Node-red-node-serialport port selection](https://discourse.nodered.org/t/node-red-node-serialport-port-selection/82651)

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**Author:** [@yhur](https://discourse.nodered.org/u/yhur)\
**Replies:** 18\
**Last updated:** [14 November 2023 06:43 UTC](https://discourse.nodered.org/t/node-red-node-serialport-port-selection/82651 "2023-11-14T06:43:04Z")

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When the node-red starts, the flow(program) picks up the hard-coded serial ports and open them. But when a device re-connects after disconnecting for any reason, it may be possible the port number change, but the end use…