What is the difference between a sensor and a transmitter?
The key difference between a sensor and a transmitter lies in their functions within a measurement system:
- Sensor: A sensor is the device that detects and measures a physical parameter (such as temperature, pressure, flow, or level) and converts it into a signal. The signal from the sensor is typically in the form of a small electrical signal (such as voltage or current), mechanical change, or resistance variation. The sensor’s role is to gather the raw data about the physical condition it’s monitoring.
- Example: A thermocouple is a temperature sensor that generates a voltage proportional to the temperature difference between two junctions.
- Transmitter: A transmitter takes the raw signal from the sensor and amplifies, processes, and converts it into a standardized output signal (typically 4-20 mA, 0-10V, or digital protocols like HART or Modbus). The transmitter makes the signal suitable for long-distance transmission to a control system or monitoring device. It ensures accurate and reliable communication between the sensor and the control system.
- Example: A temperature transmitter receives the signal from a thermocouple and converts it into a 4-20 mA output that can be sent to a PLC or DCS.
In summary, a sensor is responsible for detecting changes in the environment, while a transmitter converts and sends the sensor’s data in a format that can be used by other systems