omayma_alla33

Hello,

I am working with aS7-1500 PLC, reference 6ES7 518-47X00-1AB0, and I would like to know if it is possible to access the internal program variables (PLC) using a command.

Thank you in advance for your help.

It is unclear (to me) what you are asking. Perhaps if you give an example it would be helpful. Or perhaps tell our volunteers, which real world problem are you aiming to solve.

S7-1500 CPUs have an OPC UA server built-in. No idea if SFC steps are accessible though. The server requires additional license.

omayma_alla33

Hello, thank you for your reply.

I am working with a Siemens S7-1500 PLC and I would like to know if it is possible to access internal program variables (such as active steps in a SFC, BOOLs, INTs, or internal DB values) from an external C++ application.

My goal is to develop a C++ program that runs on an external industrial device (like an IPC or Siemens Edge device) and that can read these internal values in real time, to monitor the behavior of the PLC program.

Thanks again for your support.

Variables are called "tags" per Siemens' definition. The tags in a project needs to be set in their attributes to be visible and writable to external sources. Or you could have a communication instruction block that sends out information to a specific "client".

You mention C++ .. perhaps a visit to this site might be helpful to you: [LINK = Snap7]. The PC would collect data from the PLC in this case. This is by no means the best security, but it fits the idea you have.

Also search this forum for themes about PLC communicating with a PC using Ethernet TCP (socket) for an alternative.