2-Channel Synchro/Resolver/LVDT/RVDT High Output Drive Interface

United Electronic Industries is a leader in the PC/Ethernet data acquisition and control, Data Logger/Recorder and Programmable Automation Controller (PAC) and Modbus TCP markets.

UEI guarantees the availability of all RACKtangle®, Cube, and FLATRACK™ series products (including DNA, DNR, UEIPAC, UEISIM, UEILogger and UEIModbus chassis and compatible I/O boards, manufactured by UEI) for a minimum of 10 years.3 year warranty standard on UEI products

2-Channel High Output Drive Synchro/Resolver/LVDT/RVDT Interface
Availability: Typically in stock for 1-2 week delivery.


  • DNA-AI-256 for use with “Cube” I/O chassis
  • DNR-AI-256 for use with RACKtangle I/O chassis (requires two slots in the RACKtangle)
  • 2 input / output channels
  • 16-bit resolution
  • 3-wire (Synchro) and 4-wire (Resolver) inputs
  • 4, 5 and 6-wire LVDT/RVDT support
  • Reference output per channel
  • 5 to 18 Vrms programmable reference
  • 50 Hz to 10 kHz
  • Up to 2.4 VA without external buffer

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Synchro/Resolver/LVDT/RVDT High Output Drive Interface

Product Description

The DNx-AI-256 are high performance, two channel Synchro/Resolver input and output boards for UEI’s powerful I/O chassis. The 256 series boards are functionally similar to the DNx-AI-255 but provide significantly more output drive for applications that require it. The DNx-AI-256 series is also an ideal solution for simulating LVDT/RVDTs. The board may be configured as two inputs, two outputs, or one input and one output.

The board provides 2 input channels that will monitor either 3-wire synchros or 4-wire resolvers. The board’s high precision circuitry combined with each channel’s independent 16-bit A/D converter allow measurement accuracies up to ± 2.6 arc-minute. The inputs may be read at rates up to the excitation frequency (10 kHz max).

Each channel provides its own programmable reference with outputs independently programmable from 5 to 28 Vrms at frequencies from 50 to 10 kHz and up to 2.4 VA. When using external references, the DNx-AI-256 automatically adjusts simulated outputs for variable amplitude and frequency references in one reference cycle.

The DNR-AI-256 also provides two channels of synchro or resolver output that are ideal for driving such items as attitude indicators or as a test source for a wide variety of synchro or resolver input devices. The outputs each accept an independent reference signal and offer 16-bit output resolution. Each channel will drive up to 19.8 Vrms at 3.0 VA (total board output must be less than or equal to 5 VA) without external buffering. The current consumed by each output channel may be monitored and used to confirm the wiring is correct and the coils of the synchro/resolver or RVDT/LVDT are as expected.

The board offers 350 Vrms of isolation between channels as well as between the I/O connections and the Cube or RACKtangle chassis. Like all PowerDNA/UEILogger I/O boards, the DNR-AI-256 offers operation in harsh environments and has been tested to 3g vibration, 50g shock, -40 to +70 ºC temperatures and altitudes up to 70,000 feet.

Software for the DNR-AI-256 is provided as part of the UEI Framework. The framework provides a comprehensive yet easy to use API that supports all popular Windows programming languages and applications including LabVIEW, MATLAB/Simulink, and any application supporting ActiveX or OPC servers. Factory software drivers are also provided for Linux and most real-time operating systems including VXworks, QNX, INtime, RT Linux and more.

With the high power output of the DNR-AI-256, a fan unit should be placed in the slot next to it to prevent overheating. The fan unit, DNR-FAN-925, comes with the purchase of the AI-256.

We show you how to quickly configure LabVIEW to receive data from a United Electronic Industries synchro/resolver I/O module. In this example, the module is measuring the position of an aircraft thruster and passing along the data to the LabVIEW software running on a standard PC laptop.

Dana explains the troubleshooting process UEI’s engineering team used to evaluate an erratic flap indicator using an AI-256.