Communication netlink+ profibus with 4siemens s7-300 2DP

hello, I want to recover information via siemens s7-300 controllers in profibus network, I am connected with netlink but impossible to define on which PLC of the profibus network I can fetch the information with the s7-comm node or another s7

Could you give a bit more details on how you're trying to do it?

I've connected to several S7-300 with the node-red-contrib-s7 node and works fine with me, just following the steps in the documentation.

If you can elaborate a bit, we might find why it is not working in your case.

I am looking to recover datablock values ​​on several s7-300 PLCs connected in profibus and connect with a netlink module which is connected to the ethernet network, my problem is that node red sees the communication with netlink but I do not know how to recover the values ​​on each of the PLCs in my profibus network. sorry for my english, i m french :slight_smile:

What is the configuration of your PLCs? Rack/slot? IP?

How did you configure the S7 nodes to try and read from the PLC? Do the configuration of the nodes match the PLCs?

In which datablock and address are your variables? Did you include those in the S7 node configuration?

Is the memory access optimized? (if yes, you won't be able to read with the S7 node).

How often do you read from the PLC? What's the timeout setting?

I am already trying to make the contrib s7 or s7-comm in connected mode but it does not work.
I need to retrieve the variable from the db143 w28 block of the PLC profibus address 10.
the node parameters is the netlink address in the port is 7777, and rack 0 and slot 10 (profibus address).

I don't think the S7 node works with Netlink, since it doesn't say anything about it in the documentation. If you have any doubts, you can contact the creator on Github.

The S7 node will work if you can supply the direct IP for each PLC, as well as the Rack/Slot address.

For instance, for this PLC:


The S7 node must be configured like this:

Then it will work fine.

Profibus is a serial protocol.
You must use a Profibus to Profinet gateway.
But if its works with the node is not sure, because Profibus don't support the ISO protocol.

I totally misread "Profibus".

I'm using profinet, since the S7 node requires direct Ethernet connection with a single IP associated to each PLC in order to work.

S7-300 PLCs have an ethernet connector. Can you configure them to be accessible through it? If so, then the S7 node should work without a hitch.

sorry i m only connector profibus on plc and a connector netlink for ethenet :weary: