Well suited for industrial automation? Here are some built-in PLC features: Other than the physical layout, what makes PLCs so Particularly the external printed circuit board. However, a cost evaluation would need to consider the additional engineeringĪnd fabrication effort required, and the additional parts purchased, In quantity the consumer Raspberry Pi would be cheaper than a commercial PLC. Multi-tasking operating system not ideal for deterministic applications, andĪ detailed cost analysis wasn’t performed, but deployed The Raspberry Pi was much more capable in many ways not applicable to thisĪpplication, but was difficult to connect with field signals, used a With easy installation, straightforward programming, and consistent behavior. The Winner?įor this test, the CLICK PLC was the clear winner Operation to a level needed for a production system. Programming effort, noise filtering and timing could improve the Raspberry Pi It is believed that with additional investigation and However, the Raspberry Pi was observed to activate the output inĪ more irregular fashion. The CLICK PLC performed in a consistent and In operation, both controllers were able to maintainĪ specified outlet temperature. However, this wide-openįlexibility also means the user must carefully configure all code to perform inĪ reliable and timely manner. Languages, but Python was chosen for simplicity. Raspberry Pi controllers can be programmed in many Traditional ladder logic that executes by evaluating conditions and commandingĪctions, continuously performing scans which reliably and deterministically Like most PLCs, the CLICK is configured using The CLICK PLC and Raspberry Pi provide two radically Of many model-based industrial control implementations. Two independent input variables, tunable parameters, and one controlled output-typical Practical for a “real world” application, this design provided a system with Performance but was not part of the control loop. The output temperature was monitored to determine Two inputs, flow and incoming temperature, to anticipate and therefore control heatingĪnd provide the desired output flow temperature. Heater, or even PID-based control like an industrial process would use, weĭecided on an advanced scheme of model-based control. Instead of using simple on-off control like a home water Modelling the Processįor this comparison, we assembled a small water This insight led us to design an industrial-type project whichĬould be implemented by both a Raspberry Pi and a PLC to find out the benefitsĪnd challenges with each. Single-board microcontrollers such as the ArduinoĪnd the Raspberry Pi, are extremely inexpensive and very capable, making them foundationalįor those in the “maker” community creating various do-it-yourself applicationsĪs a hobby. Here’s a summary, click on the link above for the full text. The findings are found in the March 2020 issue of Control in an article titled Model-Based Control : Raspberry Pi vs Programmable Logic Controllers. This led author Doug Reneker to consider how a Raspberry Pi microcontroller would fare against a PLC for more advanced model-based control, where the microcontroller might have an edge. Many readers expressed considerable interest in a previous Control Design article comparing an Arduino microcontroller with a programmable logic controller (PLC) for basic flow control. Industrial PLCs for more advanced process control applications? Microcontrollers are popular with hobbyists, but how do they stand up to
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