We’ve been arguing for years about whether the ESP32 belongs on the factory floor just because it has tons of processing power, built in Wi-Fi, Bluetooth, and native peripherals. But honestly, that’s the wrong debate. The real question isn’t whether the chip can crunch the data. It's about what you need to build around it so it doesn't smoke the second it faces a real world manufacturing environment.
Let’s be real: a five dollar dev board sitting on an engineer's desk is not a PLC, and treating it like one in production is a recipe for disaster. That said, looking at today’s ecosystem with solid support for Ethernet, Modbus, CAN/TWAI, or RS-485 via external transceivers the platform has massive potential if you actually design it right.
The headaches start when you leave the lab. Throwing an ESP32 into an electrical cabinet right next to variable frequency drives (VFDs), massive contactors, and high voltage motors is a whole different ballgame. That’s where real engineering kicks in. If you want the system to survive, you need to design a proper board around it. We are talking industrial grade power supplies, absolute galvanic isolation, transient and reverse polarity protection, proper signal conditioning for 24 VDC or 4–20 mA loops, solid EMC shielding, and a decent DIN rail enclosure.
If your peripheral hardware is garbage, it doesn't matter how fast the processor is.
The beauty of this platform isn't about replacing Rockwell, Siemens, or Beckhoff. The ESP32 shouldn't be competing with the main PLC; it should be doing the dirty work the PLC wasn't meant to handle or can't do easily.
Think about that nightmare intermittent fault a random sensor dropping out once or twice a shift, driving the maintenance crew crazy. Risking a production stoppage to modify the main PLC logic just to catch a millisecond glitch is usually a hard sell. Instead, you drop a small ESP32 box in parallel, log the signal transitions locally with a timestamp to an SD card or push them over Wi-Fi to a local server, and walk away. You get a temporary, isolated diagnostic tool without touching a single line of critical process code. It’s an absolute lifesaver for rapid telemetry, custom data logging, or protocol bridging.
However, there is a hard red line here: functional safety. Just because an ESP32 can execute logic doesn't mean it should ever touch an E stop circuit, a light curtain, or a critical interlock. SIL and PL safety ratings aren’t bureaucratic nonsense. They require strict hardware redundancy, predictable fail safe modes, and architectures designed specifically not to kill anyone if the software locks up.
In industrial engineering, the ultimate question is always: “What happens when this thing hangs, loses power, or blows a transceiver?” If the answer involves severe equipment damage or human injury, the ESP32 has absolutely no business being there.
At the end of the day, the ESP32 is a fantastic tool for solving real problems fast and on a budget. It’s perfect for prototyping, building diagnostic gear that used to cost thousands, deploying distributed sensor networks, or pulling data from legacy machines into the company's IoT backend. It’s not about flooding the plant with cheap electronics; it's about having a killer wildcard in your back pocket when the factory's main automation platform leaves you blind.
