LVDT / RVDT Measurement, 4-CH


The linear variable differential transformer (LVDT) is a type of electrical transformer/transducer used for measuring linear displacement (position). A counterpart to this device that is used for measuring rotary displacement is called a rotary variable differential transformer (RVDT). Both types provide output signals (voltages) based upon an AC excitation source causing a magnetic flux generated on transformer secondary(ies) by a moveable core proportional to the linear displacement position being gauged.

NAI offers multi-channel programmable, isolated excitation and signal input, LVDT/RVDT measurement LVDT / RVDT function modules, for all the multi-function intelligent I/O cards and platforms. Covering the range of excitation voltages/ frequency, interfacing to either two, three or four wire transducers and providing a normalized digital position word based on a percentage of full scale travel, the function modules are able to interface to virtually any type LVDT or RVDT. All LVDT / RVDT modules feature background wrap-around self-test capability and most platforms support an optional programmable AC excitation supply. Utilizing state-of-the-art technologies and specialized design algorithms, many useful application features such as excitation voltage and frequency measurement, excitation loss detection and many others are “built-in." Full scale operating signal and excitation voltages/frequency between 2-28 VRMS / 47 Hz and 10 KHz can be specified (see part number). Individual excitation inputs are supplied for each channel input.

Click below for detailed function module specifications:

L*LVDT (Module L*) - Four LVDT Measurement Channels (2, 3 or 4 Wire)

Function module(s) featured in products below:

ModelBoard TypeFunction Module SlotsBoard ArchitectureSizeOn Board ReferenceEthernetOtherMaster / Slave
76C2PCI3 1/2N/A   
64E36U VME5BF533 / Cyclone III N/A2 x GB Both
64C36U VME6BF533 / Cyclone III Y2 x GB Both
64C26U VME6BF533 / Cyclone II Y1 x GB Slave
64CS46U VME5BF533 / Cyclone II Y1 x GBHigh power D/S capableSlave
76CS3PCI5 FullY High power D/S capable 
79C3PCIe3 1/2N/A   
75C33U cPCI2 + 1/2BF533 / Cyclone II  1 x GB Slave
75C53U cPCI2 + 1/2BF533 / Cyclone III  1 x GB Both
78C26U cPCI6BF533 / Cyclone II Y1 x GBHigh power D/S capableSlave
78CS26U cPCI5BF533 / Cyclone II Y1 x GB Slave
67C36U OpenVPX6BF533 / Cyclone III Y2 x GB Both
68C33U OpenVPX2 + 1/2BF533 / Cyclone IV  2 x GB Both
ModelForm FactorMax ChannelsFunctionOn Board ReferenceOther
73LD4PC 1046LVDT / RVDT MeasurementNConvection Cooled
ModelBoard TypeDimensions w/ConnectorsVolumeEst. Weight (lbs.)**Est. Power Dissipation*# of Board SlotsFunction Module SlotsMax I/O PinsEthernet
NIU1Module6.5" x 1.6" x 1.5"16.1 cu in<1.15 to 15 W01372 x GB (PoE x1)
SIU66U VME11.75" x 8.75" x 3.35"168.71 cu in<8.012 to 60 W2123162 x GB