S7 communication with Node-RED - "Error connecting to PLC: Error: read ECONNRESET"

Hello,

I have communicate between S7-1200/S7-1500 and Node-RED on IOT2040 many times in the past.

Yesterday, I installed a brand new image V2.1.3 on a IOT2040, change IP address to my needs, auto-start Node-red, installed S7 node and finally reboot before doing my flow.

I usually use the "Rack/slot" mode for the "s7 endpoint node" and access inputs/outputs and variables in DB.

Here is the current configuration to communicate with a S7-1200:

Here is the DB:

Yes, I check the checkbox "Permit access with PUT/GET communication from remote partner".

I can see my data is receive by the S7 node, but my debug window is fill with the error "Error connecting to PLC: Error: read ECONNRESET".

I never had this error in the past.

I receive my data, that's not the end of the world, but it is annoying to have a filled debug window.

Does anyone have the same issue and find a solution?

Best regards,

Hugo

Hello,

I forgot, my DB is not optimized as it should be in the current situation.

If I disconnect the PLC, here is the error I get:

Best regards,

Hugo

Hello,

Here is the response from the developper of S7 node: 

I think the issue might be with a connection leak we're having under some circumstances. In the case we have a connection problem, we currently ask the library to connect again, but without creating a new library instance, and then the connection leaks

It might be in your case that the PLC is not accepting connections anymore because of these leaked connection, and therefore it logs theseECONNRESETerrors.

I've been testing the fix for this in the past weeks, and it looks like the problem is solved. I'll publish a new version either today or tomorrow, so you can update your node and check if the problem has been fixed

FYI when I power up everything this morning, there was strangely no error in the debug window.

But I power cycled many times yesterday... strange.

Best regards,

Hugo

Hello, 

Pretty sure the S7 node create a new connection every time it can't connect or disconnect and it was the issue.

Here is the conversation I had with the S7 node developper. 

https://github.com/netsmarttech/node-red-contrib-s7/issues/18

Developper

I think the issue might be with a connection leak we're having under some circumstances. In the case we have a connection problem, we currently ask the library to connect again, but without creating a new library instance, and then the connection leaks

It might be in your case that the PLC is not accepting connections anymore because of these leaked connection, and therefore it logs theseECONNRESETerrors.

I've been testing the fix for this in the past weeks, and it looks like the problem is solved. I'll publish a new version either today or tomorrow, so you can update your node and check if the problem has been fixed

Developper 

Just published 1.5.0 that might fix the issue. Could you please update and check it? 

Me

I think you are right about the PLC not accepting connections anymore.
This morning, I reboot all the system and the S7-1200 must have reset its connection because there is no more error in the debug window.
Yesterday, I reboot Node-RED only, not the S7-1200.
So, maybe, the "leaked" connection in the S7-1200 were still count.
There is 8 S7 connections limit, maybe it was bust.

I will update S7 node to 1.5.0 monday morning and let you know if something goes wrong, else it is solve.
Thank you very much for your support, it is very appreciate!

Best regards,

Hugo

bergmanu

Hi HugoD,

thanks for this information and sharing your conversation with the node developer 

Best regards!

Hello bergmanu,

Have you experience this before?

It is the first time I do, not with the previous version of S7 node.

Best regards,

Hugo

I am getting a different error when trying to write to S7 1200.

 Hi Future incomers,

Jayatbat

I am getting a different error when trying to write to S7 1200.

"Error: PLC error [0x8104]: This service is not implemented on the module or a frame error was reported"

i followed all the steps you listed. Check the PUT/Get box. disabled optimized block access. No luck connecting. 

Anything else I,m missing?

For me this error occurred because i have not enabled "Permit access with PUT/GET communication from remote partner"




Hope this is helpful