Let me paint you a picture. It’s 11:47 PM on a Friday. The rest of the world is streaming movies or doom-scrolling social media. Me? I have a PDF of the open on my second monitor, a cold cup of coffee beside me, and a faint smile on my face.

For the uninitiated, the 1746-NR4 is a 4-channel RTD/Resistance Input Module for the SLC 500 family of PLCs. It doesn't have a touchscreen. It doesn't have Wi-Fi. It has a terminal block and a stubborn refusal to die.

Why I Spent My Friday Night Reading a 1990s PLC Manual (And You Should Too)