Modbus TCP - Node-RED

JDarius

Is there any code needed on the PLC for this application to work?

I'd like to elaborate different ways of communication between PLC and IoT2040. SO far I've tried S7 and OPC, but now I want to test modbus as well.

Is the installation and configuration of the nodes enough or do I need to write some code for the plc?

 Hello JDarius,

You have to configure the instruction "MB_Server" or "MB_Client" in the controller, I used a S7-1200.

You will find plenty of example on Siemens Industry Online Support website.

You will have a green box under your node when the IOT will be connect to the server.

Best regards,

Hugo

Hi,

You need to write Modbus TCP (Server/Client) code in S7 PLC .

Refer the below link for the same.

https://support.industry.siemens.com/cs/ww/en/view/102020340

https://support.industry.siemens.com/tf/ww/en/posts/sample-program-modbus-tcp-with-s7-1500/98690?page=0&pageSize=10

hello,

Attached video is self explanatory.

TCON_IP_V4

Interface ID is hardware id of PLC PN port=64

ID is connection id basically for serial communication (1...254)=1

Connection type is TCP =11 0r B

ActiveEstablished is false so client can establish communication= 0

Remote address as partner IP address (IOT2040)=192.168.200.1

Remote Port=0

Local Port=502(Modbus TCP server port )

And how would I configure the node?

I have the MB_Server block in the OB1 of my plc. I set the holding register at MW100. What do I have to do to read data from there?

This doens't work, it constantly changes between "failure" and "initialize".

[{"id":"ab701253.e5e73","type":"modbus-read","z":"e7f6e530.68f2b","name":"","showStatusActivities":false,"showErrors":false,"unitid":"1","dataType":"HoldingRegister","adr":"100","quantity":"2","rate":"5","rateUnit":"s","server":"b0826852.cb31d8","x":360,"y":202.66000366210937,"wires":[["35bb5341.d9fd28"],["b5bed7d6.2cb0f8"]]},{"id":"b0826852.cb31d8","type":"modbus-client","z":"","name":"1518","clienttype":"tcp","bufferCommands":true,"stateLogEnabled":false,"tcpHost":"169.254.200.15","tcpPort":"502","tcpType":"DEFAULT","serialPort":"/dev/ttyUSB","serialType":"RTU-BUFFERD","serialBaudrate":"9600","serialDatabits":"8","serialStopbits":"1","serialParity":"none","serialConnectionDelay":"100","unit_id":"1","commandDelay":"1","clientTimeout":"1000","reconnectTimeout":"2000"}]

JDarius

Is there any way to read real or bollean values? Or am I limited to using integer and words?

https://en.wikipedia.org/wiki/Modbus

Coil Read-write 1 bit

Discrete input Read-only 1 bit

Input register Read-only 16 bits

Holding register Read-write16 bits