A-308 Signal Conditioner/interface for LVDT sensor
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A-308 Universal DIN rail mounted LVDT Signal Conditioner

A. A. Lab System's A-308 is a High Accuracy, Low cost, DIN rail mounted signal conditioner designed for any LVDT application where an analog DC voltage output or 4-20mA current output is required.

DIN rail LVDT signal Conditioner

The units may also be used with any LVDT sensor. with 3,4, 5 or 6 wires, RVDT or half bridge sensors (3 wires) .

The Universal Din rail mounted LVDT Signal Conditioner is a stand-alone unit. It is powered from +9 to +28V DC (switched by the user). The LVDT transducer is connected to it via simple screw terminals. The unit will output a voltage which is highly linear (0.05%) to the displacement (limited by LVDT sensor manufacturer's specifications) or a 4-20mA current loop signal with the same linearity. The unit is mounted in a standard DIN rail case (22.5mm width).

The LVDT conditioner boards are designed around high accuracy ASIC that produces a low distortion Sine-wave excitation for driving the LVDT sensor. This ASIC also demodulates the signal from the LVDT sensor and converting it to a high accuracy, low noise signal, ready to interface with the highest accuracy A/D converter units. All sensitive components are thermally coupled on the silicon chip level, making the LVDT conditioner almost insensitive to temperature variations.

The LVDT signal conditioner board is also insensitive to Excitation level and Excitation loading due to a State-of the-art ratiometric measurement technology. The LVDT excitation is measured at real time and the output is compensated in real time for any changes in excitation voltage level.

The A-308 boards can operate with almost any type of LVDT sensor available when writing those lines. It's wide dynamic range (with wide range GAIN and DC Offset controls) make it suitable for a wide range of LVDT sensors sensitivity. The adjustment of these controls is very easy and can be done by the user using a small screwdriver.

All setups are easy for a non-trained user. Most common excitation frequencies can be set by user (16 settings) with fine tuning adjustment to match your sensor's frequency. 4 Low pass filters limit the output noise and allow you to control the dynamic response of the sensor (50Hz, 100Hz, 250Hz, 500Hz).

The A-308 DIN rail mounted LVDT Signal conditioner may also operate with very long LVDT wires by setting the internal Lead/Lag compensation network (on board).

Precision Differential Gaging - Each unit features an analog input summed or subtracted from the modules reading for configuration of difference or addition of measurements (Thickness measurements etc.)

More than 1 module can be configured together for synchronous operation of multi-LVDT sensors with the same excitation frequency and phase (Master-Slave configuration).

Polarity LED indicator on front panel for easy center (Zero) setup.

What is "Ratiometric" measurement?
The LVDT transducer contains a primary winding (input) where a sine wave excitation is connected to and one or 2 secondary output windings.
If our conditioner board is measuring only the output voltage, we will call it a "Differential" conditioner board. When we measure the output Voltage (or the difference of the output windings) and divide it by the excitation Voltage, then we call it "Ratiometric" conditioner because we measure the ratio of the output to the input
(Ratio = Vout/Vin).





DIN rail mounted LVDT

DIN rail LVDT-Open

LVDT 4 wire

The A-308 is a High Accuracy, Low cost signal conditioner, for use with most commercial LVDT sensors for accurate distance/position measurement. It’s small size and high accuracy makes it an ideal solution for many applications.

point   Small size.
point   Can be easily configured for 3,4,5,6 wire LVDT/RVDT sensors.
point   Adjustable Gain, Offset, Excitation level, Excitation frequency, Bandwidth.
point   16 user defined excitation frequencies with fine tuning adjustment. Non-Standard frequencies may be also configured at no charge.
point   4 fixed output Low-Pass filters: 50 Hz, 100Hz, 250Hz, 500Hz.
point   High linearity: 0.05%
point   Can be used as Master or Slave unit (for multiple sensor operation using the same excitation frequency and phase, to avoid interference)

point   Low drift: <50ppm/°C of F.S.
point   High frequency response: 50,100,250,500Hz. Standard, up to 20 kHz Optional.
point   Operates with remote sensor: up to 100m.
point   Operation of Half-Bridge LVDT transducer.
point   DC output proportional to position.
point   Single supply operation voltage - 12V or 24V
point   Lead-Lag phase compensation for long cable operation.

point   Built-in controls of frequency, filter, offset, gain, excitation.
point   Precision Differential Gaging - Analog "math" input is added or subtracted from current module output voltage (for connection of 2 modules with 2 sensors together).


Bandwidth: 50,100,250,500Hz.
Linearity better than 0.05% of FS
Gain Drift: 20 ppm/°C of FS max.
Offset Drift: 10 ppm/°C of FS max.
Output: Unipolar or Bipolar
LVDT sensor type: Any sensor with 3,4,5,6 wires
Supply Voltage: +9-14V or +16-28V DC
Output Voltage: ± 10V, 4-20mA
Primary to Secondary phase shift Insensitive
Transducer null voltage Insensitive
Transducer cable length: Up to 30 m
Output cable length: Up to 100 m
Excitation range: 3 - 20 V RMS
Excitation T.C. 100 ppm/°C max
Excitation Voltage Rejection 100 ppm/dB
Output Current 40 mA RMS minimum
Short Circuit Current 60 mA
Frequency range 930Hz. to 10 KHz. 13 Fixed
20Hz. to 20 KHz. preset by factory
Excitation Frequency T.C. 200 ppm/°C
THD - 50 dB
Excitation current may be increased to 500mA (optional).
Voltage range +9-14V or +16-28V DC
Current (@ no load) 40 mA
Temperature range: 0 - 70°C

Typical Applications:

3-4-5-6 wires
Connection of 3/4/5/6 wire LVDT sensors

Differential Gaging
+/-10V or 4-20mA output. Differential measurements

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A.A. Lab-Systems
Head Office: 33 Hayetzira St., Ramat-Gan 52521, ISRAEL.Tel: 972-3-5756327, Fax: 972-3-5756326
USA office: 9 Blossom drive, Kennett Square, PA19348.  Tel: (302)478-2881 Fax: (610)444-5544

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