Why Your Schneider PLC's Float32 Reads 1.4e-41 Instead of 25.5 C

You've connected your Python script to a Schneider M221, requested a holding register pair where you know the temperature is 25.5°C , and you get back: 1.401298464324817e-45 Not 25.5. Not even close. Some weird denormal float so small it might as well be zero. Welcome to the Modbus float32 byte-swap trap . It's the single most common reason engineers think pymodbus is broken when it isn't. The fix is 5 lines of code once you know what's happening — and that's what this article is about. Why this