Interlock multiple Modbus TCP Read operation to same server


i need to request many data from a single device, using Modbus TCP read; the device is used as a gateway ti other 6 slave with differente Modbus ID (e.g. ID = 1 to device 01, ID = 2 to device 2 and so on ...).
Now, i've import the library "node-red-contrib-modbus" v5.14.0.
I'm currently used the Modbus Read function with poll rate equal to 2 second. Each Read function is call on a different flow.

My question: is possible interlock the 6 Modbus Read nodes?
Is possible start Modbus Read 1; when done, start Modbus Read 2 and so on for the 6 nodes?

Thanks for any suggestions.

Have a nice day, Jumpier

Wire them in series.

modbus1 ---> change node (store data in msg.data1) --> modbus2 ---> change node (store data in msg.data2) --> modbus3 ---> change node (store data in msg.data3) --> etc etc

At the end you will have results in msg.data1 msg.data2 msg.data2 etc.

Good morning Steve,

thanks for your reply; i'm new by with Node-RED. I'm so sorry but i don't understnad your suggestion.

Can you explain me with a sample?


Pretty much as I said...

wiring in series will cause the operations to occur serially (which you asked for)

As 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.

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