# Node-red communication with NOLEK S9 via RS232

**URL:** <https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418>\
**Category:** General\
**Tags:** node-red-node-serialport\
**Created:** [7 July 2026 13:12 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418 "2026-07-07T13:12:41Z")\
**Posts on this page:** 15\
**Page:** 2

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**Author:** ![AlastairLong](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@AlastairLong](https://discourse.nodered.org/u/AlastairLong)\
**Post date:** [8 July 2026 14:31 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/21 "2026-07-08T14:31:28Z")

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I get the following response:  
dialout:x:20:root

I am logged in as root

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [8 July 2026 14:32 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/22 "2026-07-08T14:32:50Z")

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If the loopback test worked, assuming that this was using node-red, then it can't be that sort of issue.

@AlastairLong, when you said

> [@AlastairLong](#):
>
> I shorted pin 2 and 3 and the message that was sent came back.

Was that using node red to transmit and receive the data?

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**Author:** ![ghayne](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/ghayne/32/39_2.png) [@ghayne](https://discourse.nodered.org/u/ghayne)\
**Post date:** [8 July 2026 14:38 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/23 "2026-07-08T14:38:40Z")

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> [@AlastairLong](#):
>
> I am logged in as root

Is Node Red running as root?

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<div class="post-metadata">

**Author:** ![AlastairLong](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@AlastairLong](https://discourse.nodered.org/u/AlastairLong)\
**Post date:** [9 July 2026 10:11 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/24 "2026-07-09T10:11:05Z")

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Yes Node-Red is also running as root

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<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [9 July 2026 10:44 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/25 "2026-07-09T10:44:30Z")

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You haven't answered my question about your loopback test.

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<div class="post-metadata">

**Author:** ![AlastairLong](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@AlastairLong](https://discourse.nodered.org/u/AlastairLong)\
**Post date:** [9 July 2026 10:55 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/26 "2026-07-09T10:55:51Z")

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Apologies, i did run a loopback test and it worked.

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<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [9 July 2026 11:16 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/27 "2026-07-09T11:16:44Z")

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Was the loopback test in node red?

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<div class="post-metadata">

**Author:** ![AlastairLong](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@AlastairLong](https://discourse.nodered.org/u/AlastairLong)\
**Post date:** [9 July 2026 12:31 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/28 "2026-07-09T12:31:15Z")

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Yes, the loopback test was in Node-Red

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<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [9 July 2026 12:48 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/29 "2026-07-09T12:48:30Z")

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In that case you know that node red is able to send and receive ok.

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<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [9 July 2026 13:40 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/30 "2026-07-09T13:40:07Z")

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Presumably, when you removed the link between the pins, you were no longer able to see the message you sent.

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<div class="post-metadata">

**Author:** ![AlastairLong](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@AlastairLong](https://discourse.nodered.org/u/AlastairLong)\
**Post date:** [9 July 2026 13:54 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/31 "2026-07-09T13:54:39Z")

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Yes that is correct, I think I am either not sending the correct command to the NOLEK S9 unit or the RS232 connection is not enabled on the S9 unit.

Apparently using ASCI Protocol if !STATUS\* is sent to the device it should respond so i am sure the node red side is setup correctly but not the rest.

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<div class="post-metadata">

**Author:** ![ghayne](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/ghayne/32/39_2.png) [@ghayne](https://discourse.nodered.org/u/ghayne)\
**Post date:** [9 July 2026 14:25 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/32 "2026-07-09T14:25:47Z")

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> [@AlastairLong](#):
>
> Apparently using ASCI Protocol if !STATUS\* is sent to the device it should respond

You might need a Carriage Return \r - !STATUS\*\r

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<div class="post-metadata">

**Author:** ![AlastairLong](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@AlastairLong](https://discourse.nodered.org/u/AlastairLong)\
**Post date:** [9 July 2026 14:38 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/33 "2026-07-09T14:38:59Z")

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Thanks,

I have already tried that \r and \n and \r\n with no luck.  
When i change communication to RS485 I get a response but with no data it is just ""

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<div class="post-metadata">

**Author:** ![ghayne](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/ghayne/32/39_2.png) [@ghayne](https://discourse.nodered.org/u/ghayne)\
**Post date:** [9 July 2026 15:12 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/34 "2026-07-09T15:12:01Z")

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> [@AlastairLong](#):
>
> When i change communication to RS485 I get a response but with no data it is just ""

You could try a cheap USB to RS485 adapter.  
Have you found the Serial port settings on the S9?

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [7 October 2026 15:12 UTC](https://discourse.nodered.org/t/node-red-communication-with-nolek-s9-via-rs232/101418/35 "2026-10-07T15:12:30Z")

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