LVDT Interface Unit


The LIU-4 provides signal conditioning for four five-wire LVDT positioning sensors. When the LVDT sensors are being used in latency critical control systems, the conditioned signals are passed to the host ECU as four 0 to 5V analogue outputs. Where LVDT sensors are used for diagnostics or where control system speed is less critical, the signal conditioned values can be made available over the CAN bus communications link in order to reduce system harnessing.

A common primary sine wave signal is generated to supply all four LVDT sensors. This prevents beat notes being generated due to stray magnetic coupling when the LVDT sensors are used in close proximity using similar frequencies. The frequency and amplitude of the common primary signal are software programmable. The primary signal to each LVDT is individually buffered such that an overload on one sensor primary does not affect the other.

The four 0 to 5V LVDT signal conditioned analogue outputs are individually software programmable for gain and offset in order to provide more flexibility for the measurement span. LVDT sensor open circuit diagnostics are available through the CAN bus communications link


  • LVDT sensor signal conditioning


  • Four five-wire LVDT inputs with ratiometric measurement
  • Common primary signal, software adjustable frequency between 1kHz to 15kHz, and voltage between 0.5Vrms to 3.0Vrms. Maximum output current 20mArms.
  • Software adjustable gain and offset for each signal conditioned output
  • Secondary signal input range 1Vrms to 3.5Vrms
  • CAN Bus address ID analogue input
  • Unit reset input – switch to ground
  • Four 0 to 5V LVDT signal conditioned analogue outputs, with separate reference ground input
  • Internal 16-bit micro controller, 12-bit resolution ADC, Flash program memory
  • LVDT sensor open circuit diagnostics, unit internal diagnostics including internal temperature
  • CAN Bus interface, 1Mbaud standard

Electro Magnetic Compatibility

  • Complies with the essential protection requirements of EMC Directive 204/108/EC


  • Case material hard anodised aluminium
  • Estimated weight 105g

Connection Definition

  • Integral, sealed, Deutsch high density Autosport series connectors
  • LVDT connector23-wayASDD210-23PN
    Main connector11-wayASDD208-11PN


  • Supply Voltage 7.5V to 16V DC
  • Supply Voltage not to exceed 17V continuous (the unit is protected against transients and reverse polarity)
  • Current 180mA typical at 13.8V (with 10mArms LVDT primary loads)


  • Splash resistant to standard motorsport fluids
  • Lids o-ring sealed, screws sealed with silicone sealant
  • Maximum humidity 100%
  • Minimum operating temperature 0°C
  • Internal temperature not to exceed 85°C as measured by internal diagnostic sensor
  • Storage temperature -10°C to 85°C
  • Vibration 10 to 2000Hz, all axes, 24 hours
LIU-4 Mechanical Drawing
LIU-4O 030 110 012 000

Application Note



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