[thedingwing]

I don’t think this is discussed enough when PLCs are compared to other embedded systems (such as this product).

Through a PLC’s IDE, which is almost always proprietary software provided by the PLC manufacturer, a developer has the ability to view variable values, edit their values, “force” or “lock” a variable to a specific value (making assignments to that variable a no-op), and make edits to the code logic. This can all be done while maintaining the realtime guarantees of the system. These features (called “online editing” by PLC manufacturers) are essential in many applications where PLCs are used and are the biggest differentiator between a PLC and any other embedded system, such as Arduino’s products.

GDB-style debugging of a desktop program or JTAG/SWO debugging of a microcontroller can do some of what a PLC IDE can do, but it’s not as reliable and safe as PLC products.