Inductive sensors detect metallic objects without physical contact by generating an electromagnetic field. When a metal object enters this field, it changes the field’s characteristics, and the sensor outputs a signal.
🔸 Key Features
Detection Target: Only metal objects (steel, iron, aluminum, etc.)
Typical Sensing Range: 1 mm to 30 mm (depends on sensor size and type)
No moving parts: Durable and maintenance-free
Insensitive to dust, dirt, and water
🔸 Common Baumer Series
IFRM Series: General-purpose cylindrical inductive sensors
IFFM Series: Flush mountable, robust types
IFRM 08/12/18/30: Sizes (in mm) for compact to heavy-duty applications
🔸 Output Types
NPN or PNP
Normally open (NO) or normally closed (NC)
Analog output (in some models)
🔸 Applications
Detecting presence/position of metal parts
Monitoring gear teeth
Counting metallic items
End-of-travel detection on actuators
🔹 2. Capacitive Proximity Sensors (Baumer)
🔸 Principle of Operation
Capacitive sensors detect both metallic and non-metallic objects, including plastic, wood, glass, liquids, and powders. They operate by detecting changes in capacitance caused by the presence of an object.
🔸 Key Features
Detection Target: All materials (solid or liquid)
Adjustable sensitivity (manual or via teach-in button)
Can detect through non-metallic containers or walls
Sensing Range: Typically 1 mm to 25 mm
🔸 Common Baumer Series
FFRM / CFRM Series: Cylindrical or rectangular capacitive sensors
FFIR / CFIR: Advanced models with higher precision and stability
🔸 Applications
Level detection in tanks (for water, oil, grain, etc.)
Presence detection of non-metallic objects
Object counting or material verification
Detecting packaging materials
🔹 Comparison Table
Feature Inductive Sensor Capacitive Sensor
Detects Metals ✔️ ✔️
Detects Non-Metals ❌ ✔️ (glass, plastic, liquid, etc.)
Sensitivity Adjustment Rare Common (potentiometer or teach-in)
Sensing Distance Shorter Longer (depends on material)
Robustness Very high (suitable for metal) Moderate (sensitive to environment)
Common Use Metal part detection Level sensing, non-metal detection
🔹 Output & Connectivity
Digital output (NPN/PNP)
Analog output (in some capacitive sensors)
IO-Link: In smart sensors for advanced diagnostics & configuration
🔹 Wiring & Installation
Standard sizes: M8, M12, M18, M30 (cylindrical); also rectangular formats
Typically 3-wire or 4-wire connection
Shielded/unshielded types
Mounting: Flush or non-flush depending on model
🔹 Tips for Selection
Choose inductive for metal-only applications.
Choose capacitive for liquid, plastic, or non-metal detection.
Use IO-Link models if you need remote configuration or diagnostics.
Ensure the sensor’s housing and protection class (IP65/IP67/IP69K) matches the environment.
