How to read tags from S7- 200 PLC(not smart 200)

I am facing a lot of trouble in fetching data from S7-200 using S7- in node.I guess the issue is with the addressing not accepting addresses like VW10 , V40 etc.

Is S7-in node compatible with S7 200?

Please help!

Hi joey_ind,

I don't think S7-200 is supported by that node, unless you manage to get your hands on a CP243-1 Ethernet Module (very $$$ and hard to find right now). I might be wrong, let's see if @machadotiago or @gfcittolin can help here (they are involved in the node-red-contrib-s7 node developement).

There is also this node but I'm not sure if it's intended to be an extension for node-red-contrib-s7 or something "stand-alone".

As an alternative solution, in the past I was able to collect data from S7-200 plcs using the old library libnodave. It provides .NET and C++ classes to connect S7-200, 300 and 400 via the old PPI/MPI protocol. Basically you can write your own application to get data from the plc and for example publish it via MQTT (or something else) to Node-RED. Unfortunately you will need the official serial cables from Siemens or some other compatible ones (you can find some cheap stuff on amazon or ebay).

Hi MountainKing91,
Oops!..that's bad news for me .I was working on project with PLCs of AB, Omron and Siemens.
Got AB and Omron nodes to work and donno the way forward for S7. The PLC is on LAN (ethernet).

Can libnodave be used to communicate with plcs over ethernet?

I believe libnodave can be used with Ethernet connection, but the real question is: how do you connect your S7-200 to an Ethernet LAN given that the specific PLC doesn't have an Ethernet port? Can you describe your exact setup and what S7200 model do you have? As far as I remember there is no S7200 version with integrated Ethernet port.

You are right S7-200 CPU does not have an integrated ethernet port , but I am using a separate ethernet module.

Ok, so do you have a CP243 Ethernet module? You are not providing any details to let others help.

Assuming you have the CP243, you should be able to connect the plc selecting the "ISO-on-TCP" transport layer and the TSAP mode:

You will have to specify the plc ip address and I'm not sure about the port (102 is usually used with S7300, 1200 and 1500 though). Then you have to play with local and remote TSAP, just remember that usuallyTSAPs are crossed: Local TSAP "PC-side" is the Remote TSAP PLC-Side and viceversa.

In node-red-contrib-s7 docs there is no specific reference to S7200 CPUs so this might not work. I will not be able to try this since I do not have any CP243 to test.

Tried everything but could not get it to work...any ideas folks?

What did you exactly try? You did not provide any details of your setup or anything else for other people to try help you.
Aside from Node-RED, if you really have a working S7200 Ethernet module, you can try investigating the great Snap7 project by Davide Nardella.

Tried configuring the S7 node with S7200 CPU .Set the local TSAP and remote TSAP setting but I guess , the issue is not with the settings but with the format of the addresses.

Its not accepting address like VW120 etc..!!

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