What is a Sensor?
A sensor is a device that detects a physical quantity (such as temperature, pressure, distance, current, or speed) and converts it into an electrical signal. This signal can then be used for measurement, Monitoring, control, or automation.
In industrial environments, sensors are indispensable for automatic control, monitoring, and process optimisation.
🔧 What does a sensor do?
A sensor:
- Detects a physical value (e.g. temperature, position, level)
- Converts the value to a measurable electrical signal
- Forwards the signal to a Controller, PLC, HMI, or SCADA system
🧱 Examples of common sensors
| Sensor type | Quantity | Application |
|---|---|---|
| Temperature sensor | Temperature (°C) | Ovens, cooling systems, process control |
| Pressure sensor | Pressure (bar, Pa) | Pipelines, hydraulics, compressed air |
| Level sensor | Liquid level | Storage tanks, silos |
| Position sensor (Encoder) | Angular/linear position | Robot arms, motor control |
| Speed sensor | RPM or m/s | Conveyor belts, motor monitoring |
| Current sensor | Electric current (A) | Energy management, protection |
| Proximity sensor | Presence / distance | Detection on production lines |
| Light sensor (photocell) | Light intensity | Machine safety, product recognition |
🔄 Analogue vs. Digital sensors
| Type | Description |
|---|---|
| Analogue sensor | Provides a continuous signal (e.g. 4–20 mA or 0–10 V) |
| Digital sensor | Provides a binary value (on/off) or discrete signals |
🔗 Sensor and control loop
A sensor is usually the first step in a control loop. It supplies the process value that is compared to a Setpoint. Depending on the deviation, the control loop adjusts the system.
🏭 Where are sensors used?
- Industrial automation (machine monitoring, process control)
- Food and beverage industry (temperature, hygiene control)
- Energy management (measuring consumption and voltage)
- Building management (climate control, lighting)
- Automotive industry (position, pressure, speed)
📌 In summary
A sensor is a measuring instrument that converts physical information into electrical signals, allowing systems to measure, respond, or self-adjust automatically.