Node-red-contrib-melsec Configuration

General
1

Hello everyone,

I am trying to connect a Mitsubishi FX3G-60M PLC to my Raspberry Pi using Node-RED. My goal is just to read some data to display on my dashboard.

I'm using the node-red-contrib-melsec-fx nodes and am having trouble configuring the serial port (e.g., /dev/ttyACM0).

I thought the serial port settings would be inside the melsec-fx-in node, but I can't find them. The node only asks me to select a "Melsec FX endpoint," as you can see in this screenshot:

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I guess the serial port configuration must be inside that "Melsec FX endpoint" node, but I don't know how to access or edit it.

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Could someone please point me in the right direction?

Thank you!

2

Hi, welcome to the forum

Have you tried clicking the pencil button to the right of "Melsec FX endpoint"?

As you are a new user, I recommend watching this playlist: Node-RED Essentials. The videos are done by the developers of node-red. They're nice & short and to the point. You will understand a whole lot more in about 1 hour. A small investment for a lot of gain.

3

Hi @Steve-Mcl,

I clicked the pencil icon as you suggested:

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That opened the endpoint configuration node, which shows these options:
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I am trying to retrieve data from the Mitsubishi PLC using its programming port, not the Ethernet port, which is why I was looking for the serial settings.

My confusion came from the fact that I have some experience retrieving data from Siemens PLCs using Node-RED, and those nodes handle the connection settings differently."

4

Yeah, I have not used that node and seen you were a new user and (wrongly) assumed you were also new to Node-RED (they are still worth a watch if you've not seem them - a few good tips and tricks in there)

So, i am surprised there is no serial settings on that config node also!?
However, a clue lies in the nodes source code: node-red-contrib-melsec/red/melsec.js at abdf6d71013873bf44908f79cf3ec175f2e78065 · st-one-io/node-red-contrib-melsec · GitHub

if (!melsecAdapter) return that.error('Missing "@protocols/node-melsec" dependency, avaliable only on the ST-One hardware. Please contact us at "st-one.io" for pricing and more information.')

I.e. it looks like this requires ST-One hardware (and I guess thats where the setup is done)

If you are familiar with JavaScript, you could DIY this in a function node using node-fxplc node module. The readme has example code on how to connect serial and read/write addresses

See article Use any npm module in Node-RED for getting started with npm node modules.