👁️ The Industrial Sensor Field Guide: Identification & Use

In an automated facility, sensors act as the “senses” of the machine. Choosing the right sensor depends entirely on what material you are trying to detect and the environment it lives in. This guide covers the most common types of proximity and presence sensors used in the Bravo shop and beyond.

🏗️ 1. Inductive Proximity Sensors

🛠️ The “Metal-Only” Specialist

Inductive sensors are the workhorses of heavy machinery. They create an electromagnetic field that only reacts when metal enters the zone.

• Best For: Detecting gear teeth, metal levers, or steel parts in a jig.

• Key Advantage: They are nearly indestructible and completely ignore non-metallic contaminants like oil, water, or dust.

• Limitation: They have a very short “reach” (usually less than 1 inch).

⚡ 2. Capacitive Proximity Sensors

🛠️ The “Universal” Detector

These sensors detect changes in electrical capacitance. Because almost anything can hold an electrical charge, these sensors can “see” almost anything.

• Best For: Detecting non-metallic objects like plastic, wood, or glass.

• Key Advantage: They can “see through” certain materials. For example, a capacitive sensor can detect the liquid level inside a plastic tank without touching the liquid.

• Limitation: Highly sensitive to humidity and moisture.

🔦 3. Photoelectric & IR Sensors

🛠️ The “Long-Range” Optical Eyes

These use light beams (usually Infrared) to detect the presence or distance of an object. They come in three distinct configurations:

• Through-Beam: A separate transmitter and receiver. The “trigger” happens when the beam between them is broken. (Highest range and reliability).

• Retro-Reflective: A sensor that bounces light off a dedicated reflector. Ideal for detecting pallets or large boxes.

• Diffuse: Bounces light directly off the object itself. No reflector is needed, making it the easiest to install in tight spots.

🔊 4. Ultrasonic Sensors

🛠️ The “Sound Wave” Specialist

Similar to a bat’s sonar, these emit a high-frequency sound pulse and time how long it takes to echo back.

• Best For: Measuring distance or detecting clear objects (like glass or clear plastic) that optical sensors might miss.

• Key Advantage: They don’t care about the color or transparency of the object.

• Limitation: Can be “confused” by loud industrial noises or soft materials (like foam) that absorb sound.

🔍 Summary Selection Table

💡 Pro-Tip: Flush vs. Non-Flush

When selecting a sensor, look at the tip:

• Flush Mount: The plastic face is “shielded” by the metal body. It can be buried level with a metal surface.

• Non-Flush: The plastic tip sticks out past the metal body. These have a longer sensing range but must have a “clear zone” around the tip to prevent false triggers from the mounting bracket itself.