Sensor Class Reference

Learn more about the available sensor class types.

FlexLogger supports the following sensors. The sensor classes available in your system depend on your specific hardware configuration and the type of physical measurement you are acquiring.

For descriptions and additional information of the supported physical measurements, refer to the Physical Measurement Type Reference.

Table 20. Sensor Class Types
Sensor Class Description
Voltage Determines the electrical potential difference between two points on a circuit.
Current Determines the current in a circuit and generates a voltage or current reading proportional to the detected current.
Current Shunt Measures current by determining the voltage drop across a low-resistance precision resistor.
Bridge Bridge sensors operate by correlating a physical phenomena, such as strain, temperature, or force, to a change in resistance in one or more legs of a Wheatstone bridge. The general Wheatstone bridge is a network of four resistive legs with an excitation voltage (VEX) that is applied across the bridge. One or more of these legs can be active sensing elements.
IEPE Integrated Electronics Piezoelectric (IEPE) transducer that is packaged with a built-in amplifier. Because the charge produced by some sensors is very small, the electrical signal produced by the transducer is susceptible to noise, and sensitive electronics must be used to amplify and condition the signal. An IEPE sensor integrates the sensitive electronics as close as possible to the transducer to ensure better noise immunity and convenient packaging. These sensors require a 4-20 mA current excitation to operate.
Thermocouple Uses the temperature-dependent voltage produced at the junction of two dissimilar metals to measure temperature. This voltage is nonlinear with respect to temperature so thermocouples require signal conditioning.
Pulse Counter Measures the number of non-zero inputs (pulses) in the signal over a specified time.
Encoder
  • (Angle) Measures 360-degree angular rotation using A, B and Z signals to determine position and direction. The signal can be only digital.
  • (Linear) Measures displacement with any number of pulses per millimeter.
RTD Temperature-sensing device with resistance that increases with temperature. An RTD is usually constructed with wire coil or deposited film of pure metal. RTDs can be made of different metals and have different nominal resistances, but the most popular RTD is platinum and has a nominal resistance of 100 Ω at 0 °C.
Frequency Counter Measures the number of pulses of a periodic signal over a specified time.
LVDT

Determines linear displacement by converting the measurement of movement along a linear axis into an AC electrical signal.

For information on wiring your LVDT sensor, refer to the Connecting LVDT and RVDT Signals section of the NI PXIe-4340 User Manual.
RVDT

Determines angular displacement by converting the measurement of movement along a rotational axis into an AC electrical signal.

For information on wiring your RVDT sensor, refer to the Connecting LVDT and RVDT Signals section of the NI PXIe-4340 User Manual.
Resistance Determines resistance by sending a current through a resistor and measuring the voltage drop from the signal before and after it crosses the resistor.