Read/Write data from Omron (NJ501-1400) PLC into node-red


I need to connect Omron (NJ501-1400) PLC with the node-red. Is there some node (like node-red-contrib-s7 for Siemens PLC) to communicate with the Omron PLC ? What could be the most suitable way to establish connection?

Thanks in advance!

Try using the forum search ( the magnifying glass) for the word "Omron"

Depending on the firmware level and version of NJ, you may well have OPCUA built in.

If so, I'd recommend using the IIOT nodes.

If not, then there isn't a great deal of FINS or EtherNet/IP type nodes I'm afraid.

You could always use write some ladder with socket services in the PLC and use the TCP nodes as a last option.

2 other options...
There are some MQTT function blocks available for the NJ / NX PLCs. I've used them and they work.

The NJ PLC is a mighty fast PLC and it would be capable of running logic to implement MODBUS TCP. There may be some

Some links...


take a look at this project. It has MQTT Client connect, pub and sub FBs in a library.

Thanks you very much for the detailed answer. I will see and try different options!

Hi Steve,

Today i read and write some tags from/to Omron (NJ501-1400 Firmware version 1.19) by using node-red-contrib-opcua node through OPC UA. It works for me.

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Glad I could help.

To help others in the future, it would be really good if you could indicate which node(s) you used, maybe export & post a an example flow and perhaps even some screenshots?

Cheers, Steve.

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Im trying to make connection between Omron NJ501-1400 and rasberry pi trough Node-Red
node-red-contrib-opcua node. But I have some problems with certificates. OPC UA server from PLC keep rejecting client certificate. Have you solved this? Or can you give me an advice how to do that?

@Ondrej I cant help you on the OPCUA certificate issue but if you are needing to get data from the PLC, you could try using FINS...

I must also add - for the NX and NJ series PLCs you might be better off using MQTT directly.

There are FBs (Function Blocks) available for...

  • reading and writing JSON
  • publishing and subscribing to MQTT

Of course I must also point out that going down the MQTT route requires you to add FB libraries and LADDER/ST to the PLC in order to generate the MQTT messages - whereas the OPCUA/FINS method requires no ladder to read/write values.

I use both methods depending on the situation.

As far as I remember, this P/N has Ethernet/IP protocol built in, if yes you can simply use the node

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