[Editor's note] Read the related content regarding this project: Meet the industrialized Arduino and Tips for using an industrialized Arduino controller
To answer this question, we must think about this demonstration not as a temperature controller, but that it represents any kind of small-scale controller project. What are the other alternatives?
Also read: PLC vs. Arduino for industrial control
A conventional Arduino has many capabilities; it is inexpensive; and it is easy to program using C or C++. To many engineers, this is a very clear choice, but not without its drawbacks. First, there’s the physical fragility. Second, various interfaces, such as reading a temperature sensor or other type of industrial instrument, must be built from scratch. Read www.controldesign.com/arduino for an illustration of this situation in greater detail.
A small PLC can also handle the necessary control requirements, and it will have accessories designed to act as interfaces to those external devices along with power supplies. It will also be more physically robust and easier to assemble using standardized interconnections and DIN-rail mounts. A PLC has more robust software with background utilities that identify when problems are developing and can warn the operator or shut down to a safe state. These capabilities are not part of the native Arduino IDE. The main downside of a PLC in this context is its higher cost combined with its ladder-logic programming environment, which is foreign to a typical maker.
An industrialized Arduino, such as the AutomationDirect ProductivityOpen, is a useful compromise between those two extremes:
- Industrial form factors overcome the fragility of unprotected boards and simplify connectivity.
- Modular interfaces for industrial sensors and peripherals are available.
- Hardware versatility allows use of industrial and maker devices, including DIY adaptations.
- Programming using C and C++ is possible, along with other platforms, including ProductivityBlocks.
However, the lack of protective and housekeeping software functions available from a PLC should give an engineer pause to ask, “What could potentially happen with this system if the controller fails?” An engineer considering a small-scale project has some critical questions to ask, but it is always helpful to have the widest variety of options available.
