Arduino Unveils the Opta, Its First “Micro PLC” for Industrial IoT

Re:Arduino Unveils the Opta, Its First “Micro PLC” for Indus... by idiotsecant on Friday November 11, 2022 @10:33AM (#33562054)

The most fundamental miss here is the lack of live code editing. One of the basic things that makes PLCs a separate thing is that you can edit code live without stopping execution of the device. In real automation applications you can't shut down a plant or a line or a generator or whatever just because you want to add a new E-stop or change the timing on an actuator slightly or tune a PID etc.

If you have to kill the machine to recompile this is not a PLC by any stretch of the imagination, it's an Arduino with a fancy box.

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Re:Arduino Unveils the Opta, Its First “Micro PLC” for Indus... by PaulWaldman on Friday November 11, 2022 @11:57AM (#33563271)

I don't know about that. Siemens S7 PLCs are not capable of online edits and they have a massive install base.

In the Rockwell / Allen-Bradley world, almost all PLCs support online edits.

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Re:Arduino Unveils the Opta, Its First “Micro PLC” for Indus... by idiotsecant on Sunday November 13, 2022 @01:32PM (#33585877)

>Siemens S7 PLCs

>Real PLCs

I don't think we're talking about the same thing!

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Re:Arduino Unveils the Opta, Its First “Micro PLC” for Indus... by thedingwing on Friday November 11, 2022 @12:08PM (#33563443)

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.

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