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 achieve something like this. I’m familiar with the modbus read and buffer parser…

[image] BambosD: i used a template node with output parsed json and feed the flex getter Usually you would use a Change node for this. Why do you need to use a template?

thank you very much, this was the issue. now i have all devices. [image] what would be the recommended to merge those ?? change node ?

is just for easier reading and typing. with template i have it like this: { "fc":3, "unitid":100, "address":51003, "quantity":2 } with a change node everything is populated in a single text box like below: [image]

Yes, or a function node. What I dont understand is why do you always access the same modbus server and same address for these values? If all values are from the same modbus server/unit ID, then you could do this all in one request and one buffer parser.

yes, is proof of concept now using only the first device. in reality is 4 different devices as the prototype here, and unfortunately with different encoding methods. (the usual modbus headache). How it sounds to you to merge all the devices json objects with a change node and JSONata expression ?

[image] BambosD: How it sounds to you to merge all the devices json objects with a change node and JSONata expression ? It depends what you want to do with the final data and what else (additional to bom) will be in the final data.

the end goal is to aggregate all the values to a single key/value object so we can inject to mysql node with topic insert into table… now the messages are aggregated and i’m looking how to merge all the incoming data to a single object of keys/values because in mysql node need to be all together to…

in which case I would set the values in to a sub property like msg.data and use a common name for the bom values (e.g value), then use a simple function that loops over each key and gathers the .value of each sub property in msg.data [image] [{"id":"b87a6f58b4d9da38","type":"inject","z":"9a5fb6c7…

Thank you Mr. Steve, in reality the structure would be 3 or 4 modbus devices with 4 or 5 values as output of each buffer parser. the function probably will not work as it is, but is charming how it executes on each item with loop. I just understand how to use all the messages in a template.. it’s…

[image] BambosD: in reality the structure would be 3 or 4 modbus devices with 4 or 5 values as output of each buffer parser Which is why I said [image] Steve-Mcl: It depends what you want to do with the final data and what else (additional to bom) will be in the final data

Node-RED

Node-RED Forum

Modbus to mySQL flow suggestions

General

smanjunath211 7 August 2025 06:33 28

this thread may interest you...

Topic		Replies	Views
Multiple injections at the same time? General	12	4116	29 January 2021
Query via Modbus TCP -> MSSQL - zero values General database , modbus	11	427	5 February 2023
Using payload from Modbus Flex Getter to query mySQL database on phpmyadmin General	14	827	28 July 2021
Doing Calculations on Modbus data General	16	1595	17 December 2020
ModbusTCP on node-red is it possible for 50 devices? General	36	1868	5 February 2021

Copyright OpenJS Foundation and Node-RED contributors. All rights reserved. The OpenJS Foundation has registered trademarks and uses trademarks. For a list of trademarks of the OpenJS Foundation, please see our Trademark Policy and Trademark List. Trademarks and logos not indicated on the list of OpenJS Foundation trademarks are trademarks™ or registered® trademarks of their respective holders. Use of them does not imply any affiliation with or endorsement by them.

Modbus to mySQL flow suggestions

Related topics