Sensors are the eyes and ears of industrial automation. They detect, measure, and report on everything from part presence to temperature, pressure to position. Selecting the right sensor for each application is critical—the wrong choice leads to false triggers, missed detections, and unreliable systems. This guide covers the major sensor types used in Singapore's manufacturing sector and how to choose the best option for your application.
Proximity Sensors
Proximity sensors detect the presence of objects without physical contact. They're workhorses of industrial automation, used for position detection, counting, and object presence verification.
Inductive Proximity Sensors
Detect metallic objects using electromagnetic fields. Reliable and cost-effective for ferrous metal detection.
- Sensing range: 1-50mm typical
- Best for: Steel, iron, aluminum
- IP67/IP68 ratings available
Capacitive Proximity Sensors
Detect any material including plastics, liquids, and powders. Measure changes in capacitance.
- Sensing range: 1-25mm typical
- Best for: Non-metallic materials
- Level sensing through tank walls
Photoelectric Sensors
Photoelectric sensors use light to detect objects, offering longer sensing distances and the ability to detect transparent or reflective objects.
Through-Beam
Separate transmitter and receiver units. Highest reliability and longest range.
- Range: Up to 60m
- Best for: Harsh environments
- Detects any opaque object
Retro-Reflective
Emitter and receiver in one unit, reflecting off a separate reflector.
- Range: Up to 15m
- Easier installation
- Polarized versions for shiny objects
Diffuse Reflective
Single unit detecting light reflected directly from the target object.
- Range: Up to 2m
- Simple installation
- Background suppression available
Fiber Optic
Light transmitted through flexible fibers to remote sensing heads.
- Miniature sensing heads
- Tight spaces and high temps
- Immune to EMI
Temperature Sensors
Temperature measurement is critical for process control, equipment protection, and quality assurance.
| Type | Range | Accuracy | Best Application |
|---|---|---|---|
| RTD (PT100) | -200°C to +850°C | ±0.1°C | High-precision process control |
| Thermocouple | -270°C to +2300°C | ±1-2°C | High temperatures, fast response |
| Thermistor | -50°C to +150°C | ±0.2°C | HVAC, consumer products |
| Infrared | -40°C to +3000°C | ±1% | Non-contact, moving targets |
Pressure & Force Sensors
Pressure sensors measure force per unit area in gases and liquids, while force sensors measure mechanical loads.
Pressure Transducers
Convert pressure to electrical signals for process monitoring and control.
- Gauge, absolute, differential types
- 4-20mA or 0-10V output
- Ranges from vacuum to 10,000 bar
Load Cells
Strain gauge-based force measurement for weighing and force monitoring.
- Accuracy to 0.02% FS
- Single point to multi-axis
- Capacities: grams to tonnes
Singapore's Tropical Climate
High humidity and temperatures require sensors with appropriate IP ratings and temperature specifications. We recommend IP67 or higher for factory floor applications, and conformal-coated electronics for outdoor or wash-down environments.
Position & Displacement Sensors
Measuring exact position is essential for motion control, quality inspection, and process verification.
Linear Encoders
High-precision position measurement using optical or magnetic scales.
- Resolution to 0.1 micron
- Absolute or incremental
- CNC and metrology applications
LVDT/LVIT
Linear variable differential transformers for robust analog position measurement.
- Infinite resolution
- No wear (non-contact core)
- Harsh environment capable
Laser Distance Sensors
Non-contact measurement using time-of-flight or triangulation.
- Range: mm to hundreds of meters
- Accuracy to 1mm
- No target preparation needed
Ultrasonic Sensors
Sound-based distance measurement, unaffected by color or transparency.
- Range: 30mm to 10m typical
- Level sensing in tanks
- Works with any material
Vision Systems
Machine vision goes beyond simple presence detection to analyze images for inspection, measurement, identification, and guidance.
Applications
- Quality inspection – Detecting defects, verifying assembly, checking labels
- Measurement – Non-contact dimensional verification
- Identification – Reading barcodes, QR codes, OCR
- Robot guidance – Locating parts for pick-and-place operations
- Color verification – Ensuring correct components or markings
Sensor Selection Criteria
Choosing the right sensor requires balancing multiple factors:
- Detection target – Material, size, shape, surface finish
- Sensing distance – Required range and mounting constraints
- Environment – Temperature, humidity, dust, chemicals, washdown
- Response time – How fast must the sensor react?
- Output type – Digital (NPN/PNP), analog, communication protocol
- Accuracy & repeatability – How precise must measurements be?
- Cost – Initial purchase and lifecycle costs
Integration with Control Systems
Modern sensors offer various connectivity options:
- Discrete I/O – Simple on/off signals to PLC digital inputs
- Analog signals – 4-20mA or 0-10V to analog input modules
- IO-Link – Smart sensor communication with diagnostics and parameterization
- Industrial Ethernet – EtherNet/IP, PROFINET, EtherCAT for high-speed data
Need Help Selecting Sensors?
Our automation engineers can help you select and integrate the right sensors for your application.
Contact Us