# I changed to UDP From TCP for Mitsubhishi PLC Fx3u but did not worked in Nodered

**URL:** <https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518>\
**Category:** Industrial\
**Created:** [27 October 2025 14:25 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518 "2025-10-27T14:25:24Z")\
**Posts on this page:** 20\
**Page:** 1

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**Author:** ![Jayeshpitale1](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jayeshpitale1/32/70216_2.png) [@Jayeshpitale1](https://discourse.nodered.org/u/Jayeshpitale1)\
**Post date:** [27 October 2025 14:25 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/1 "2025-10-27T14:25:24Z")

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I changed to UDP From TCP for Mitsubishi PLC Fx3u but did not work in NodeRED  
as per the previous Topic @Steve-Mcl told me to Change it from TCP to UDP and i did but its not working now

> [@How to connect Mitsubishi plc fx3u and Fx5u with node red](https://discourse.nodered.org/t/how-to-connect-mitsubishi-plc-fx3u-and-fx5u-with-node-red/92205/4):
>
> Sorry, but I cannot understand this. Q1: What is the IP, Gateway and Mask of the PLC? Q2: What is the IP, Gateway and Mask of the computer where Node-RED is running? Q3: Show me what "Open Settings" you have in the FX3u PLC Q4: Show me a screen shot of the MC Protocol config node as you have set it up in Node-RED NOTE: I have 20y experience of Mitsi PLCs + data collection. I can pretty much predict your life every 2~4 weeks - you will be resetting the PLC because the TCP connection has lo…

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<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [27 October 2025 14:32 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/2 "2025-10-27T14:32:11Z")

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What do you see? how did you setup PLC? are node-red server and PLC on same network?

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<div class="post-metadata">

**Author:** ![Jayeshpitale1](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jayeshpitale1/32/70216_2.png) [@Jayeshpitale1](https://discourse.nodered.org/u/Jayeshpitale1)\
**Post date:** [27 October 2025 14:33 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/3 "2025-10-27T14:33:14Z")

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I just see timeout error in nodeRED and both are in same network both are pinging  
@Steve-Mcl

```json
{
  "POLLING": "ENABLED",
  "payload": null,
  "_msgid": "e722627803c06cc2",
  "_event": "node:30608999c586eb0a",
  "topic": "D40,9",
  "_linkSource": [
    {
      "id": "0530ddbb9d9908a47f8fc8a21d81",
      "node": "93091528e94e02c3"
    }
  ],
  "mcReadDetails": {
    "request": {
      "outputFormat": "Array",
      "address": "D40,9",
      "timeStamp": 1761575618296
    },
    "response": {
      "isGood": false,
      "quality": [
        "Unknown",
        "Unknown",
        "Unknown",
        "Unknown",
        "Unknown",
        "Unknown",
        "Unknown",
        "Unknown",
        "Unknown"
      ],
      "TAG": "D40,9",
      "addr": "D40,9",
      "timeTaken": 4501,
      "timeStamp": 1761575622797,
      "value": [
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0
      ],
      "valueType": "INT",
      "deviceCode": "D",
      "deviceCodeNotation": "Decimal",
      "deviceCodeType": "WORD",
      "digitSpec": "",
      "dataType": "INT",
      "dataTypeByteLength": 2,
      "deviceNo": 40,
      "problem": true
    },
    "error": true
  },
  "error": {
    "message": "Error",
    "source": {
      "id": "05cd47ebd2cf785f",
      "type": "MC Read",
      "name": "",
      "count": 1
    },
    "stack": "Error\n at handleError (/home/omsoftware/.node-red/node_modules/node-red-contrib-mcprotocol/nodes/read.js:74:17)\n at PLCItem.myReply [as cb] (/home/omsoftware/.node-red/node_modules/node-red-contrib-mcprotocol/nodes/read.js:207:11)\n at MCProtocol.readResponse (/home/omsoftware/.node-red/node_modules/node-red-contrib-mcprotocol/mcprotocol/mcprotocol.js:1797:14)\n at MCProtocol.packetTimeout (/home/omsoftware/.node-red/node_modules/node-red-contrib-mcprotocol/mcprotocol/mcprotocol.js:465:8)\n at Timeout.<anonymous> (/home/omsoftware/.node-red/node_modules/node-red-contrib-mcprotocol/mcprotocol/mcprotocol.js:1383:24)\n at listOnTimeout (node:internal/timers:583:11)\n at process.processTimers (node:internal/timers:519:7)"
  }
}

```

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<div class="post-metadata">

**Author:** ![Jayeshpitale1](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jayeshpitale1/32/70216_2.png) [@Jayeshpitale1](https://discourse.nodered.org/u/Jayeshpitale1)\
**Post date:** [27 October 2025 15:16 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/4 "2025-10-27T15:16:35Z")

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@Steve-Mcl ,  
Can you Please Tell me what i am missing. or am i wrong

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**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [27 October 2025 15:17 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/5 "2025-10-27T15:17:25Z")

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> [@Jayeshpitale1](#):
>
> Can you Please Tell me what i am missing. or am i wrong

Not without information

> [@Steve-Mcl](#):
>
> how did you setup PLC?

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<div class="post-metadata">

**Author:** ![Jayeshpitale1](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jayeshpitale1/32/70216_2.png) [@Jayeshpitale1](https://discourse.nodered.org/u/Jayeshpitale1)\
**Post date:** [27 October 2025 15:27 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/6 "2025-10-27T15:27:32Z")

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i have updated in plc setting

 ![IMG-20251027-WA0006](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/b/7/b722a08dc2df29bbb7aed061e83032ec13c0a2b1.jpeg)  
 ![IMG-20251027-WA0039](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/a/5/a511110649db60a9df16a4fdb4dcf3f576e36604.jpeg)  
 ![IMG-20251027-WA0037](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/f/4/f405889ee6d197c495c9ed2be7ef3a34c32f4c64.jpeg)  
 ![IMG-20251027-WA0036](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/0/0/00d634903f446111cadf80e6f342ecccdbc90d5a.jpeg)

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<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [27 October 2025 15:54 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/7 "2025-10-27T15:54:30Z")

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Can you show me the settings you have made in the config node?

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<div class="post-metadata">

**Author:** ![Jayeshpitale1](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jayeshpitale1/32/70216_2.png) [@Jayeshpitale1](https://discourse.nodered.org/u/Jayeshpitale1)\
**Post date:** [27 October 2025 16:13 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/8 "2025-10-27T16:13:52Z")

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@Steve-Mcl ,  
here is the config

 ![screenshot](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/8/4/84ef4bec545c9651ea18b29e5df72b33868efb36.png)

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<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [27 October 2025 16:21 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/9 "2025-10-27T16:21:10Z")

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### Test1:

1. Try changing the PLC to 5500 / 5500  
 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/2/4/24dd2ddea9ce1ebabddd09e3ee8b50ab7d414829.jpeg)
2. power off / on the PLC (to apply new settings)
3. Change the config to match  
 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/c/b/cbb29d22988a967df263ac320345462ea55ce137.png)

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<div class="post-metadata">

**Author:** ![Jayeshpitale1](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jayeshpitale1/32/70216_2.png) [@Jayeshpitale1](https://discourse.nodered.org/u/Jayeshpitale1)\
**Post date:** [28 October 2025 08:24 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/10 "2025-10-28T08:24:44Z")

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@Steve-Mcl ,  
Hi there i dont know whether it will work on that or not are your sure about the solution you gave because before i have using TCP with the above config it was working

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**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [28 October 2025 08:29 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/11 "2025-10-28T08:29:59Z")

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> [@Jayeshpitale1](#):
>
> are your sure about the solution you gave

No. That's why I called it **Test1**

If it does not work I will probably provide a **Test2**

  

FYI: I have not used that particular PLC model, I am not familiar with your network hardware, routing, settings, etc, etc, etc. In short, I dont have enough details (nor do I have enough time to ask for and wait for answers) so I am taking a logic step-wise approach and asking you to "try stuff".

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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:** [28 October 2025 09:53 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/12 "2025-10-28T09:53:35Z")

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> [@Jayeshpitale1](#):
>
> both are in same network

Are they on the same network segment? IE connected to the same router, not through another router or wifi mesh or similar.

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**Author:** ![Jayeshpitale1](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jayeshpitale1/32/70216_2.png) [@Jayeshpitale1](https://discourse.nodered.org/u/Jayeshpitale1)\
**Post date:** [28 October 2025 13:31 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/13 "2025-10-28T13:31:17Z")

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@Colin ,

> [@Colin](#):
>
> Are they on the same network segment? IE connected to the same router, not through another router or wifi mesh or similar.

Yes there is a special router for the plc and device we separated the router for them and they are in same network .

@Steve-Mcl

> [@Steve-Mcl](#):
>
> FYI: I have not used that particular PLC model, I am not familiar with your network hardware, routing, settings, etc, etc, etc. In short, I dont have enough details (nor do I have enough time to ask for and wait for answers) so I am taking a logic step-wise approach and asking you to "try stuff".

What details are required more please specify me so i can try to provide you with that.

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<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [28 October 2025 14:12 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/14 "2025-10-28T14:12:41Z")

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> [@Jayeshpitale1](#):
>
> What details are required more please specify me so i can try to provide you with that.

> [@Steve-Mcl](#):
>
> nor do I have enough time to ask for and wait for answers

Please try the suggestion first.

If that doesn't work, we will explore other ideas.

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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:** [28 October 2025 14:57 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/15 "2025-10-28T14:57:03Z")

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> [@Jayeshpitale1](#):
>
> Yes there is a special router for the plc and device we separated the router for them and they are in same network

I don't fully understand that sentence, but if there are two routers between you and the plc then udp may not get through, even if logically you are on the same network.

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<div class="post-metadata">

**Author:** ![Jayeshpitale1](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jayeshpitale1/32/70216_2.png) [@Jayeshpitale1](https://discourse.nodered.org/u/Jayeshpitale1)\
**Post date:** [28 October 2025 16:49 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/16 "2025-10-28T16:49:08Z")

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@Colin ,  
In simple word there is only 1 router for plc and device

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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:** [28 October 2025 21:00 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/17 "2025-10-28T21:00:26Z")

</div>

> [@Jayeshpitale1](#):
>
> there is only 1 router for plc and device

It's not that then.

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<div class="post-metadata">

**Author:** ![Jayeshpitale1](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jayeshpitale1/32/70216_2.png) [@Jayeshpitale1](https://discourse.nodered.org/u/Jayeshpitale1)\
**Post date:** [7 November 2025 10:43 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/18 "2025-11-07T10:43:28Z")

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@Steve-Mcl and @Colin,  
I have updated to ur port and tried but still not worked timeout and also i tried port 5000  
which screenshot is below

 ![IMG-20251107-WA0007](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/1/c/1c2ef24816636d22495ff5853501d23935875e0f.jpeg)

i have got updated in nodered but still i cant use it

 ![ssc](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/3/a/3a4419255b0261ed06ba6c0fe670f8cc98f2a975.png)

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<div class="post-metadata">

**Author:** ![jbudd](https://avatars.discourse-cdn.com/v4/letter/j/5f8ce5/32.png) [@jbudd](https://discourse.nodered.org/u/jbudd)\
**Post date:** [7 November 2025 12:38 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/19 "2025-11-07T12:38:06Z")

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Bear in mind that i know zero about industrial PLCs.

Steve suggested using port 5500 both in the PLC config and in Node-red. Did you try this?

To my untutored eyes it looks like the PLC is sending data to port 5001 while Node-red is listening on port 5000?

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<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [7 November 2025 15:58 UTC](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518/20 "2025-11-07T15:58:20Z")

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avoid 5000 and 5001

**5000** is often the UDP **default** for protocols that support **Auto Open UDP Port** features, or when configured for certain SCADA systems/HMIs.  
| **5001** is often the **default** TCP for communication like SCADA, HMIs, or other clients connecting to the PLC's dedicated Ethernet module (e.g., QJ71E71).

[Next page](https://discourse.nodered.org/t/i-changed-to-udp-from-tcp-for-mitsubhishi-plc-fx3u-but-did-not-worked-in-nodered/99518.md?page=2)