Difference between the Siemens ET 200SP and S7-1200/1500?

The general difference between a Siemens ET 200SP and a Siemens S7-1200 or S7-1500 is that ET 200SP is a remote I/O system that can be used as a PLC, and the S7 devices are classic PLCs.

Overall the ET 200SP PLC version can function as a standalone machine control PLC, with the functionality similar to the S7-1500 family of controllers.

It is more expensive than the S7-1200 but it incorporates a lot of I/O cards so you wouldn't spend additional money on it. So in places where many I/O cards and control are used, it is a better and cheaper way to use than the S7-1200, coming with greater memory and better CPU.

When it comes to smaller projects and the low count of I/O modules needed, then an S7-1200 would probably be a better option than the ET 200SP.

Of course, when it comes to details in performance, both of the controllers, ET 200SP and the S7-1200 have a certain limitation when it comes down to high-end level functions, but in general, when it comes to programming/coding, the difference is very minor.

Compared with the S7-1500, the Siemens ET 200SP is a little bit different form of the same controller, incorporating probably the majority of the same functions and features, but gets the new functions in later releases and has fewer diagnostics functions.