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Mount and remove safety USB from Datalayer (PLC or Node Red)

Mount and remove safety USB from Datalayer (PLC or Node Red)

Long-established Member


A customer wants to save files created by him on the USB.
The problem is that if the USB is not mounted and then the remove safely command is performed before removing the USB, the files are not saved.

This is a problem because my customer does not want to leave access to the CtrlX Core Web Server, but to do everything through an external HMI (WebVisu).
I have been trying to run these commands through RestApi with Postman and it works. I can mount and remove safely the USB via Postman.
The problem is when I try to do it with Node Red or with the PLC, with the CXA_Datalayer library, I get the DL_Type_Mismatch error or the PLC DL_Unsupported error.

I attach NodeRed code and PLC screenshot.
Does anyone know how to write the node address and the Value in JSON format to be able to execute these commands from PLC.

Thank you very much.




You have to use the rest APIs in node-red not the nodes. The nodes are design to interact with the datalayer. I upload an example with the ethercat node. i see if i can reproduce shortly the USBs also



This is the example you wanted 🙂

Hello Mauro,

Thank you for the example, it works quite well,

Do you know if it is possible to do it from the PLC?

Many thanks,

I don't think so since are rest calls, you can trigger something from the PLC but the rest code will be in node-red.


There are also libraries to do https requests via PLC, so you could do exactly the same. But mostly these libraries are not free of charge.

Good morning

In case you may be interested, I attach a recipe management manual, which also includes how to "mount" the USB from the PLC part in combination with the Nodered, using part of what Mauro Riboni did.



Best Regards

Jordi Laboria