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LD1

4 Channels, 2-28 Vrms Input, 47 Hz-1 kHz

A linear variable differential transformer (LVDT) is a type of electrical transformer/transducer used for measuring linear displacement (position). A counterpart to this device used for measuring rotary displacement is called a rotary variable differential transformer (RVDT). The RVDT is like an LVDT in that it measures a positional displacement, however, the displacement, which is still a linear proportional function, is based on rotary instead of linear positional movement.

Both types provide output signals (voltages) as a proportional linear function based upon an AC reference source. The AC Reference source applied at the transformer primary winding causes a magnetic flux generated on the transformer secondary windings by a moveable core, which causes output signal(s) proportional to the linear displacement position being gauged.

With isolated excitation and signal input covering 2, 3, or 4-wire transducer interfaces and a normalized digital position word based on a percentage of full-scale travel, these modules can interface to virtually any type LVDT or RVDT transformer. The design has the capability to automatically shift to higher bandwidths when high acceleration events are encountered. There is no data latency. The shifting is smooth and continuous with no glitches.

In addition to state-of-the-art technologies and specialized design algorithms, the modules include many other useful application features such as:

  • All channels have continuous background Built-In-Test (BIT)
  • Signal, reference and frequency measurements
  • Signal under-voltage and over-voltage detection
  • Reference under-voltage and over-voltage detections
  • Support an optional, programmable AC excitation supply

Specifications
  • Resolution: 24-bit
  • Input Format: Linear Variable Differential Transformer (LVDT), Rotary Variable Differential Transformer (RVDT), 2, 3, or 4-wire programmable
  • Input Voltage: 2 - 28 Vrms
  • Reference Voltage: 2 - 115 Vrms
  • Input Impedance: 300 kΩ
  • Accuracy: ±0.025% FS 3-wire or 4-wire and 2-wire w/ compensated phase, ±0.050% FS for 2-wire, uncompensated phase
  • Bandwidth: Default factory setting is 40 Hz. Bandwidth is field programmable on a per channel basis. User must program all parameters for each boot up, or parameter will be set to the default value.
  • Frequency Range: 47 Hz - 1 kHz
  • Phase Shift: Automatically compensates for phase shifts between the transducer excitation and output up to ±60° (3 and 4-wire configurations). Programmable fixed compensation is provided for 2-wire configurations.
  • Self-Test: Built-in wraparound self-test.
  • Power: 5 VDC @ 1 A
  • Ground: Isolated signal and excitation. Channels individually isolated from each other and from system ground.
  • Weight: 2.5 oz. (71 g)
Block Diagram

(Click diagram to enlarge)

Documentation
5/13/2021 4:25:23 PM
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