The Scaling In measurement and automation technology, this refers to the conversion of a sensor signal into a physical measurement value. In this process, electrical signals such as voltage, current, or resistance are mapped to a defined measurement range so that the measured values can be directly expressed in physical units such as °C, bar, l/min, N, or kW.
Scaling ensures that raw signals from sensors and transducers are interpreted correctly and can be used for analysis, control, or process monitoring.
Why is scaling necessary?
Sensors often do not provide their measured values directly in physical units, but rather as standardized electrical signals. Typical output signals include:
- 0 … 10 V
- ±10 V
- 0 … 20 mA
- 4 … 20 mA
- mV signals
- Frequency signals
Scaling is required so that, for example, a current signal of 4 … 20 mA can be converted to a pressure value of 0 … 100 bar or a level of 0 … 10 m.
Linear Scaling
For many measured variables, there is a proportional relationship between the input signal and the measured value. In this case, a linear scaling used.
Example: Pressure Measurement
| Input signal | |
|---|---|
| 4 mA | 0 bar |
| 12 mA | 50 bar |
| 20 mA | 100 bar |
The measured current value is then scaled proportionally to the defined measurement range.
Linear scaling is often used in:
- Pressure Sensors
- Level Sensors
- Flow measurements
- Force sensors
- Performance Measurements
Nonlinear Scaling
Some sensors do not have a linear response curve. In these cases, a nonlinear scaling take place.
Typical examples include:
- Thermocouples
- Pt100 and Pt1000 Sensors
- Humidity Sensors
- Specialized Process Sensors
With thermocouples, for example, the voltage generated does not increase in proportion to the temperature. For this reason, predefined calibration curves or mathematical correction methods are used to precisely calculate the actual temperature.
Scaling in Modern Measurement Systems
Modern measurement data acquisition systems handle scaling automatically. Users simply specify the measurement range and the desired physical unit. The system then calculates the actual measurement values in real time.
This results in numerous advantages:
- Direct Display of Physical Values
- Greater measurement accuracy
- Consistent Data Analysis
- Simplified Configuration
- Reducing Operator Errors
- Automatic Processing of Large Amounts of Data
Scaling with Delphin Measurement Data Acquisition
The measurement data acquisition systems from Delphin Technology support both linear and nonlinear scaling. This allows a wide variety of sensors and measured variables to be directly acquired and converted into physical units. The Delphin solutions enable the processing of temperature, pressure, current, voltage, frequency, and numerous other sensor signals without additional signal conditioning. In addition, measured values can be immediately visualized, stored, and analyzed.
Particularly when measuring thermocouples, Pt100 sensors, and other nonlinear sensors, stored calibration curves and intelligent signal processing ensure precise and standards-compliant conversion of the measured values. The flexible measurement data acquisition supports applications in laboratories, on test benches, in process monitoring, and in industrial plants.
Benefits of Proper Scaling
- Accurate Representation of Physical Quantities
- Consistent and reproducible measurement results
- Easy integration of various sensors
- Support for linear and nonlinear characteristic curves
- Optimized Process Monitoring
- Reliable evaluations and analyses
- Fundamentals of Automation and Control Engineering
Properly configured scaling is therefore a crucial component of any professional measurement data acquisition system and ensures that sensor signals are converted into meaningful and reliable measurement values.