What the two digits in an IP rating mean, the real difference between IP67, IP68 and IP69K, how NEMA ratings compare, and how to pick for washdown and outdoor use.
What flush (shielded) and non-flush (unshielded) proximity sensors are, how much range each gives, and how to mount them so they don't false-trigger.
Mechanical limit switches and non-contact proximity sensors compared on life, speed, environment, wiring and cost, with a guide to choosing.
How ultrasonic sensors measure distance with sound, what affects accuracy, and when to choose them over photoelectric or capacitive sensors.
A step-by-step way to tell whether a proximity sensor is bad, using the LED, a multimeter or a sensor tester, for PNP, NPN and 2-wire sensors.
What normally open and normally closed really mean, how to read the symbols, and when to choose NO or NC for switches, relays and sensors.
IO-Link turns ordinary sensor cables into a digital link for data, settings and diagnostics. How it works, masters and hubs, port classes, and when it pays off.
How the three main photoelectric sensing modes work, their ranges and weak spots, and how to choose the right one for your target.
M12 4-pin, 5-pin and 8-pin pinouts with wire colors, what A, B, D, X, S, T and L coding mean, and how to choose the right cordset.
