Operation Manual
ATA-2001 LVDT/RVDT Signal Conditioner
Measurement Specialties Inc. www.meas-spec.com phone: +1-800-745-8008
1000 Lucas Way, Hampton, VA 23666, United States 8 of 17 fax: +1-757-766-4297
Rev. 3 / July 2015
A separate cable with two shielded twisted pairs of wires is recommended for hook-up between the
transducer and the P1 plug. Proper low capacitance instrumentation cable should be used to insure best
performance and compliance with CE standards for emissions and susceptibility. Belden™ 8723 or
equivalent cable is recommended. The ATA-2001 utilizes a four wire synchronous demodulator and
therefore does not require connection to the transducer secondary (output) center tap. Six-wire LVDTs
and RVDTs must have external center tap jumpers installed as close to the transducer as possible.
At 2.5 kHz, most LVDT/RVDTs can operate with cable runs of up to 350 feet (over 100 meters).
However, depending upon design characteristics, some are less tolerant of cable capacitance, and may
exhibit adverse effect on linearity. If you experience difficulty with calibration, consult the factory for
additional information about cabling effects on specific models.
Particular attention must be given to proper shield termination to prevent ground loops and EMI
interference with the transducer signal. Single shield, multiple twisted pair cable is not recommended for
multiple transducer installations (see the Master/Slave Operation section of this manual). Separate
cables for each transducer will yield best results. See hook-up diagrams and shielding recommendations
below.
Contact our factory for jumper cables sold as accessories for our LVDT and RVDT models.
4.2 Output Wiring & Schematics
The output signals are available at the P2 connector on the rear panel. This connector is a five-position,
"Euro" style, plug-in, screw terminal barrier strip. It was chosen for its ease of use and small footprint.
Once all of the connections are made, the amplifier may be removed and reinstalled without
disconnecting the individual wires. The wire clamps are designed to accept stripped and tinned wires with
no soldering required. The ATA-2001 has several output signal options. They are as follows:
Voltage output
Bipolar Voltage: Most LVDTs may be calibrated for ±10, or ±5VDC output, corresponding to plus
and minus full scale displacement of the transducer from its null position.
Unipolar Voltage: Single ended calibration options are, 0 to 10, or 0 to 5VDC for minus to plus full
displacement of the transducer. Half the calibrated full scale DC voltage is at transducer null. For
example, 0 to 10VDC calibration would have an output of 5VDC at the transducer null position.
Current output
The 4 to 20mA current output is most beneficial in applications with long signal runs. The signal
maintains a constant current in the control loop for a given sensor position. Changes in loop
resistance or voltage, within operating parameters, will not affect the position signal. Current loops
also have greater resistance to electromagnetic and radio frequency interference. A shielded,
twisted, wire pair is recommended for best immunity.
4 to 20mA internal loop power: Used when no external loop power supply is available. The internal
power supply of the ATA-2001 provides the voltage (18VDC) necessary for the current loop. This
feature should not be used with current receivers configured to supply loop power.
4 to 20mA external loop power: This option allows operation of the ATA-2001 with powered
receivers. Using an external 24 to 28 VDC power supply increases the allowable loop resistance.
