One Interference voltage is an unwanted electrical voltage that is superimposed on a wire or measurement circuit in addition to the actual measurement signal. It is usually caused by electromagnetic or capacitive coupling from the surrounding environment and can significantly impair the accuracy of measurements.
Particularly in industrial facilities with numerous electrical loads, motors, switchgear, or variable-frequency drives, interference voltages occur regularly and pose a challenge to precise measurement data acquisition.
How do interference voltages occur?
Interference is often caused by electromagnetic fields emanating from nearby electrical lines or devices.
Common causes include:
- Energy and signal lines laid in parallel
- Power lines carrying 50-Hz or 60-Hz alternating current
- Electric Motors
- Frequency converters
- Contactors and relays
- Switching Operations in Electrical Systems
- High-Current Power Lines
- Radio and High-Frequency Sources
For example, if a sensitive measurement line runs parallel to a power supply line over long distances, the well-known Mains hum be coupled into the measurement signal. This results in distorted measurement values or increased signal noise.
Impact on Measurement Technology
Interference can significantly impair the quality of measurement data. Possible consequences include:
- Fluctuations in measured values
- Signal-to-noise ratio
- Inaccurate measurement results
- Misinterpretations of Measurement Data
- False Alarms in Threshold Monitoring
- Communication Problems
- Reduced measurement resolution
Sensors with low signal levels are particularly affected, for example:
- Thermocouples
- Pt100 Sensors
- Strain gauge
- Pressure Sensors
- mV measurements
- Vibration Transducer
The smaller the actual useful signal, the greater the impact of coupled noise voltages.
Methods for Preventing Interference Voltage
To minimize measurement errors, various protective measures are used in professional measurement technology:
Galvanic isolation
The electrical isolation of measurement channels prevents compensation currents and reduces the coupling of interference.
Shielded cables
Shielded cables reduce interference from electromagnetic fields.
Physical Separation
Signal and power lines should be run separately whenever possible.
Differential Measurement
Differential measurement techniques can automatically compensate for many interference voltages.
Filtering
Analog and digital filters reduce high-frequency noise and power supply hum.
Proper Grounding Designs
A well-designed potential equalization system prevents ground loops and unwanted interference currents.
Interference Voltage and Delphin Measurement Systems
The measurement data acquisition systems from Delphin Technology are designed for use in industrial environments and feature various measures to enhance measurement reliability. These include, among other things, galvanically isolated inputs and high immunity to electromagnetic interference. This allows even sensitive measurement signals to be reliably recorded.
In addition, Delphin measurement technology supports the direct acquisition of a wide variety of sensor signals, such as thermocouples, Pt100 sensors, and current, voltage, or frequency signals. High-quality signal conditioning and intelligent data processing help minimize interference and ensure precise measurement results.
Why is it important to prevent interference voltages?
Effectively reducing interference voltages ensures:
- Greater measurement accuracy
- Reliable Process Monitoring
- Improved Data Quality
- Lower error rates
- Greater operational reliability
- More precise analyses and evaluations
Especially in test benches, laboratories, production facilities, and monitoring systems, controlling electromagnetic interference is an essential prerequisite for reliable measurement data.
Typical Applications
Interference plays a role in:
- Research and development
- Industrial Data Acquisition
- Test Bench Technology
- Energy and Power Measurement
- Process Automation
- Vibration analysis
- Temperature measurement
- Laboratory Applications
- Condition Monitoring
- Machine monitoring