Ametek DN VR-608 Series User manual

DNx-VR-608
User Manual
8-Channel Variable Reluctance Sensor Interface
for the PowerDNA Cube and RACK Series Chassis
February 2024
PN Man-DNx-VR-608
© Copyright 1998-2024 United Electronic Industries, Inc. All rights reserved.

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WARNING!
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Products sold by United Electronic Industries, Inc. are not authorized for use as critical components in
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DNx-VR-608 Variable Reluctance Interface i
Table of Contents
February 2024 www.ueidaq.com
508.921.4600
© Copyright 2024
United Electronic Industries, Inc.
Table of Contents
Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Organization of this Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Manual Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Naming Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.4 Related Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.5 Before You Begin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.6 DNx-VR-608 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.6.1 Measurement Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.6.2 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.6.3 Digital Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.6.4 Isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.6.5 Environmental Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.6.6 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.6.7 Software Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.7 Technical Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 2 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1 VR Sensor Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.1 Index Tooth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.1.2 Torque Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2 DNx-VR-608 Device Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2.1 Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2.2 Zero Crossing Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2.3 ADC Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.2.4 Counter/Timer Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.2.5 Digital Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.2.6 Sync Out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.3 Measurement Resolution and Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.3.1 Timed Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.3.2 N-Pulse Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.3.3 Timed Pulse Period Measurement Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.3.4 Torque Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.4 Indicators and Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.5 DNA Cube Jumpers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.6 Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.6.1 Loopback Test Wiring (Rev. 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Chapter 3 PowerDNA Explorer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.2 VR-608 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Chapter 4 Programming with the High-level API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.1 About the High-level API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.2 Example Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

DNx-VR-608 Variable Reluctance Interface ii
Table of Contents
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4.3 Create a Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.4 Resource Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.5 Configure VR Channels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.5.1 Configure Analog VR Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.5.2 Configure Torque Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.5.3 Configure Digital Input (Rev. 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.5.4 Configure Digital Input (Rev. 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.6 Configure Digital Output Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.6.1 Generate Simulated VR Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4.6.2 Route Source to Digital Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4.6.3 Digital Output Dividers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
4.7 Configure Sync Out (Rev. 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
4.8 Configure the Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.9 Start the Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.10 Read Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.10.1 Read Velocity, Position, Tooth Count. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.10.2 Read Torque (Rev. 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.10.3 Read FIFO Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.10.4 Read ADC Diagnostics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.10.5 Read Status Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.11 Stop the Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Chapter 5 Programming with the Low-level API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5.1 About the Low-level API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5.2 Example Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5.3 Data Acquisition Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.4 Point-by-Point API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.4.1 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.4.2 Enable Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
5.4.3 Read Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.4.4 Read Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
5.4.5 Stop Cleanly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
5.5 RtDMap API. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Appendix A Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
A.1 Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
A.2 Screw Terminal Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

DNx-VR-608 Variable Reluctance Interface iii
List of Figures
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List of Figures
Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter 2 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2-1 Variable Reluctance Sensor and Toothed Wheel........................................................8
2-2 Example VR Sensor Signals .......................................................................................9
2-3 Z-Tooth Types ...........................................................................................................10
2-4 Dual VR Sensor Torque Measurement......................................................................11
2-5 Simplified Block Diagram of the DNx-VR-608 ...........................................................12
2-6 Logic Block Diagram for a Dual VR IC Channel ........................................................14
2-7 Adaptive Peak Threshold (APT) from the MAX9926 Specification............................14
2-8 DNx-VR-608 Counter/Timer Module..........................................................................16
2-9 Photo of DNR-VR-608 Board ....................................................................................22
2-10 DNA-VR-608 Jumper Address Location ....................................................................22
2-11 Pinout Diagram of the DNx-VR-608...........................................................................23
2-12 Example Wiring for Torque Simulator Loopback .......................................................24
Chapter 3 PowerDNA Explorer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3-1 PowerDNA Explorer for DNx-VR-608 ........................................................................26
Chapter 4 Programming with the High-level API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Chapter 5 Programming with the Low-level API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Appendix A Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
A-1 Pinout and Photo of DNA-STP-37 Screw Terminal Panel .........................................55

DNx-VR-608 Variable Reluctance Interface iv
List of Tables
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List of Tables
Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1-1 Specifications ...............................................................................................................7
Chapter 2 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2-1 Peak Threshold and Zero Crossing Modes ................................................................15
2-2 Counter/Timer Register Data......................................................................................17
2-3 DNx-VR-608 LED Indicators.......................................................................................22
2-4 DNx-VR-608 Pinout Descriptions ...............................................................................23
Chapter 3 PowerDNA Explorer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Chapter 4 Programming with the High-level API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4-1 High-level API for VR Channel Configuration.............................................................29
4-2 Digital Output Sources for UeiVRSimulatedModeStatic .............................................34
4-3 CUeiSimulatedVRChannel Methods for Digital Output Dividers.................................35
4-4 Sync Out Sources Supported by the CUeiVRSyncOutLine Class..............................35
4-5 VR Data returned by Read().......................................................................................37
4-6 Data read from FIFO ..................................................................................................38
4-7 ADC Status Register ..................................................................................................39
4-8 CUeiVRReader Status Methods................................................................................40
4-9 Bit Assignments for ReadAlarmStatus() .....................................................................41
Chapter 5 Programming with the Low-level API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5-1 Low-level DNx-VR-608 API Functions........................................................................44
5-2 Low-level API Configuration Parameters....................................................................45
5-3 DMap Channels..........................................................................................................53
Appendix A Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

DNx-VR-608 Variable Reluctance Interface
Chapter 1 1
Introduction
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Chapter 1 Introduction
This document outlines the feature-set of the DNx-VR-608 Variable Reluctance
Interface boards and their use in a wide variety of motion and rotation monitoring
applications.
The following sections are provided in this chapter:
•Organization of this Manual (Section 1.1)
•Manual Conventions (Section 1.2)
•Naming Conventions (Section 1.3)
•Related Resources (Section 1.4)
•Before You Begin (Section 1.5)
•DNx-VR-608 Features (Section 1.6)
•Technical Specification (Section 1.7)
1.1 Organization
of this Manual
This DNx-VR-608 User Manual is organized as follows:
• Introduction
Chapter 1 summarizes the features and specifications of the
DNx-VR-608.
• Functional Description
Chapter 2 describes the device architecture, logic, and connectivity of
the DNx-VR-608.
• PowerDNA Explorer
Chapter 3 shows how to explore DNx-VR-608 features through a
GUI-based application.
• Programming with the High-level API
Chapter 4 describes how to create a session, configure the session, and
interpret results with the UeiDaq Framework API.
• Programming with the Low-level API
Chapter 5 provides an overview of programming the DNx-VR-608 using
the low-level C API.
• Accessories
Appendix A provides a list of accessories available for use with the
DNx-VR-608.

DNx-VR-608 Variable Reluctance Interface
Chapter 1 2
Introduction
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1.2 Manual
Conventions
The following conventions are used throughout this manual:
Tips are designed to highlight quick ways to get the job done or to
reveal good ideas you might not discover on your own.
CAUTION! advises you of precautions to take to avoid injury, data
loss, and damage to your boards or a system crash.
NOTE: Notes alert you to important information.
1.3 Naming
Conventions
The DNA-VR-608, DNR-VR-608, and DNF-VR-608 board versions are
compatible with the UEI Cube, RACKtangle, and FLATRACK chassis
respectively. These boards are electronically identical and differ only in
mounting hardware. The DNA version stacks in a Cube chassis, while the DNR
and DNF versions plug into the backplane of a Rack chassis. Throughout this
manual, the term DNx-VR-608 refers to both Cube and Rack products.
1.4 Related
Resources
This manual only covers functionality specific to the DNx-VR-608. To get started
with the UEI IOM, please see the documentation included with the software
installation. On Windows, these resources can be found from the desktop by
clicking Start » All Programs » UEI
UEI’s website includes other user resources such as application notes, FAQs,
tutorials, and videos. In particular, the glossary of terms may be helpful when
reading through this manual: https://www.ueidaq.com/glossary
Additional questions? Please email UEI Support at [email protected] or
call 508-921-4600.
Typeface Description Example
bold field or button names Click Scan Network
» hierarchy to get to a specific menu item File » New
fixed source code to be entered verbatim session.CleanUp()
<brackets> placeholder for user-defined text pdna://<IP address>
italics path to a file or directory C:\Program Files

DNx-VR-608 Variable Reluctance Interface
Chapter 1 3
Introduction
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1.5 Before You
Begin
No Hot Swapping!
Before plugging any I/O connector into the Cube or RACKtangle, be sure to
remove power from all field wiring. Failure to do so may cause severe damage
to the equipment.
Check Your Firmware
Ensure that the firmware installed on the Cube or Rack CPU matches the UEI
software version installed on your PC. The IOM is shipped with pre-installed
firmware and a matching software installation. If you upgrade your software
installation, you must also update the firmware on your Cube or RACK CPU.
See “FirmwareUpdatingProcedures” for instructions on checking and updating
the firmware. These instructions are located in the following directories:
•On Linux: <PowerDNA-x.y.z>/docs
•On Windows:
Start » All Programs » UEI » PowerDNA » Documentation

DNx-VR-608 Variable Reluctance Interface
Chapter 1 4
Introduction
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1.6 DNx-VR-608
Features
DNx-VR-608 boards are 8-channel, variable reluctance (VR) sensor interface
boards. The DNA/DNR/DNF-VR-608 boards are electronically identical and
differ only in the hardware needed to mount the board in the selected chassis.
The board is designed for use in a wide variety of motion and rotation monitoring
applications. It can also be used as a general-purpose counter to measure AC
signals and TTL-level digital signals, including the output from a Hall Effect
sensor. This manual includes information for both Revision 1 and Revision 2
VR-608 boards.
Features of the DNx-VR-608 (Rev. 1 and Rev. 2) include:
•8 fully differential analog input channels
•Input range from 50 mV to 250 V peak-to-peak
•Bipolar (VR) inputs rates up to 300 kHz
•Unipolar (Hall/TTL) input rates up to 18 kHz
•Conditioned inputs can be routed to TTL digital outputs
•Adaptive Threshold input mode
•True zero-cross detection
•Inter-tooth timing allows acceleration tracking
•Open circuit detection
Additional features available on Rev. 2 boards only:
•4 isolated TTL digital inputs can be routed to internal counters
•Alarms for open circuit, stalled rotation, and overspeed conditions.
Alarms can be routed to digital outputs.
•Torque measurement for dual VR sensor systems
•Digital Hall Effect sensor simulator
•Timed Pulse Period Measurement (TPPM) Mode that features a
dynamic sampling window based on input frequency.
1.6.1 Measurement
Capabilities
The DNx-VR-608 contains eight differential analog input channels designed to
support an extremely wide variety of variable reluctance sensors. Sensor
compatibility is made possible by the board’s wide input range (50 mVpp to
250 Vpp) and high input impedance (40 kΩ). The board supports a maximum
pulse rate of 300 kHz for inputs ≥ 3.2 Vpp; measurable pulse rates for lower
signal levels are shown in Table 1-1.
Signal peaks and zero crossings may be configured for auto-detection. For
example, an “Adaptive Peak Threshold” (APT) mode sets the threshold to 30%
of a time-averaged input. A watchdog circuit resets the input to the minimum
threshold level if the input “drops out” for 85 milliseconds. Another APT mode
auto-computes the thresholds from the minimum and maximum voltages
measured by the board.
Users can also set zero crossing thresholds and peak thresholds to fixed voltage
levels for special use cases such as Hall Effect measurements and custom
signal conditioning applications.
Revision 2 boards provide four digital input channels for reading sensors which
already output a conditioned TTL-level signal. Digital inputs bypass the front-end
VR circuitry for a faster read rate.

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1.6.2 Operating
Modes
The DNx-VR-608 supports the following per-channel modes:
• Timed Count/Frequency: counts the number of teeth detected during a
specified time interval and returns velocity in teeth/sec or RPM.
• N-Pulse: measures the time taken to detect N teeth and returns velocity
in RPM.
• Z-Pulse: measures the number of teeth and the time elapsed between
two Z/Index pulses (The Z/Index tooth is usually a gap or a double tooth
on the encoder wheel).
• Timed Pulse Period Measurement (TPPM): counts the number of
edges detected within a default measurement window to calculate RPM.
The measurement window dynamically increases when needed to
accommodate slower input frequencies. TPPM is for continuous signals
only, i.e., wheels with no Z-tooth (Revision 2 only).
Channel pairs may be configured for the following modes:
• Quadrature Encoder: measures relative position and rotational
direction from a quadrature encoder sensor
• Torque: measures torque in dual-sensor systems by comparing the
timing of the pulses from each sensor (Revision 2 only). Torque Mode is
for analog signals only.
1.6.3 Digital
Outputs
The DNx-VR-608 provides four isolated TTL-level digital outputs that change
state on the threshold crossing of the input waveform. This allows the board to
be used as a signal conditioning front end for existing TTL-based counter test
systems. The board supports a matrix configuration where any input can be
directed to any or all of the digital outputs. See Section 2.2.5 for more
information on supported digital output features for the DNx-VR-608.
On Revision 2 boards, digital outputs may also be used for Z-tooth detection, for
open circuit, stalled rotation, or overspeed alarms, or for generating simulated
VR pulse trains. Also, signals on the internal sync bus can be routed to the
digital outputs.
For applications where the VR-608 is primarily used as a signal conditioner, the
input to DOut mapping can be set to start running at power up, even if the host
Cube or RACK is not running any application software.
Dividers of 2, 4, 8, or 16 can be applied to signals that are routed to the digital
outputs. The signals can be inverted, i.e., phase shifted. The output pulse will
always have a 50% duty cycle.
1.6.4 Isolation The DNx-VR-608 offers 350 Vrms of isolation between itself and other I/O
boards as well as between the I/O connections and the chassis. In addition, the
inputs are divided into four sets of channel pairs, and each two-channel pair is
isolated from the others. Each isolated channel pair is also supported with a
logic level digital output.
1.6.5 Environmental
Conditions
Like all UEI I/O boards, the DNx-VR-608 offers operation in extreme
environments and has been tested to 5 g vibration, 100 g shock, temperatures
from -40 to +85 °C, and will function at altitudes up to 70,000 feet.

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1.6.6 Accessories All field-wiring connections to the DNx-VR-608 are made through a standard
37-pin D connector, allowing OEM users to build custom cabling systems
through off-the-shelf components. Users may also connect the DNx-VR-608
board to UEI’s DNA-STP-37 screw terminal panel via the DNA-CBL-37 cables.
1.6.7 Software
Support
The DNx-VR-608 includes a software suite supporting Windows, Linux, QNX,
VxWorks, RTX, and most other popular real-time operating systems. Windows
users may use the UEIDAQ Framework, which provides a simple and complete
software interface to Windows programming languages and DAQ applications
(e.g., LabVIEW, MATLAB). All software support includes extensive example
programs that make it easy to cut-and-paste the I/O software into your
applications.

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1.7 Technical
Specification
Table 1-1 summarizes the technical specifications for the DNx-VR-608 board.
All specifications are at 23 °C ±5 °C and apply to both Rev. 1 and Rev. 2 boards
unless otherwise noted.
Table 1-1 Specifications
Number of VR channels 8
Channel configuration Differential
Channel isolation 4 isolated banks of two channels
Input impedance > 40 kΩ and < 250 pF
Input voltage range Up to 250 Vpp
Maximum pulse rate (bipolar,
VR input mode)
300 kHz at ≥ 3.2 Vpp
200 kHz at ≥ 2.1 Vpp
100 kHz at ≥ 1.1 Vpp
50 kHz at ≥ 0.5 Vpp
25 kHz at ≥ 0.25 Vpp
10 kHz at ≥ 0.125 Vpp
≤ 5 kHz at ≥ 0.08 Vpp
Minimum detectable input
(VR input mode) 50 mVpp, fixed input mode
Max pulse rate (unipolar/TTL
mode) 500 kHz (Vlow < 1.2 V, Vhigh > 2.2 V)
Measurement Accuracy see Section 2.3
Inter-tooth timing
Time-base resolution 15.15 ns
Counter depth 32-bits
Timing measurement range 20 µs to 65 seconds
Overvoltage protection 300 Vpp
Input FIFO size Rev. 1: 512 x 32
Rev. 2: 2k x 32
DOut simulation accuracy
(continuous mode) 0.5% of expected frequency
General Specifications
Power dissipation < 3 W
Isolation 350 Vrms
Operating temperature Tested -40 °C to +85 °C
Operating humidity 0% to 95%, non-condensing
Vibration IEC 60068-2-6
IEC 60068-2-64
5 g, 10-500 Hz, sinusoidal
5 g (rms), 10-500 Hz, broadband random
Shock IEC 60068-2-27 100 g, 3 ms half sine, 18 shocks @ 6 orientations
30 g, 11 ms half sine, 18 shocks @ 6 orientations
Altitude 120,000 ft
MTBF 180,000 hours

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Chapter 2 Functional Description
This chapter describes the device architecture, hardware, and functionality of
the DNx-VR-608 Variable Reluctance Interface. The following sections are
provided in this chapter:
•VR Sensor Overview (Section 2.1)
•DNx-VR-608 Device Architecture (Section 2.2)
•Measurement Resolution and Accuracy (2.3)
•Indicators and Connectors (Section 2.4)
•DNA Cube Jumpers (Section 2.5)
•Pinout (Section 2.6)
2.1 VR Sensor
Overview
Variable reluctance (VR) sensors are electromechanical transducers used to
measure the rotational speed and position of a crankshaft. The VR sensor
consists of a permanent magnet surrounded by a coil of wire. A toothed wheel
made of a ferrous material is attached to the crankshaft, and the VR sensor is
positioned close to the teeth (Figure 2-1).
Figure 2-1 Variable Reluctance Sensor and Toothed Wheel
When a tooth rotates past the sensor, the distance between the wheel and
sensor changes, changing the magnetic flux through the pickup coil. An AC
voltage is induced across the coil as shown in Figure 2-2. In the default polarity,
voltage is positive when the tooth approaches the sensor and negative when the
tooth moves away. Notably, the positive-to-negative zero crossing coincides with
the center of the tooth.
V
d
N
S

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Figure 2-2 Example VR Sensor Signals
A VR interface board reads in the analog waveform and conditions it into a
digital signal (Figure 2-2). The digital signal goes high when a positive to
negative zero crossing (ZC) is detected and resets to low when the signal level
rises above a certain threshold. Therefore, rising edges of the pulse train
correspond to tooth detections. The pulse train feeds into a digital counter/timer
which measures the number of teeth and the time between teeth. Raw data can
then be used to calculate shaft properties such as rotational speed, acceleration,
position, and torque.
Note that VR sensors are sensitive to noise. Use best practices when wiring the
device and shielding signals.
ZC APT
Toothed
Wheel
VR Analog
Signal
VR Digital
Signal
tooth detected reset ZC comparator

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2.1.1 Index Tooth On some toothed wheels, one tooth is a different height or width than the others.
This tooth is called the “index tooth” or “Z-tooth.” The Z-tooth changes the
frequency and amplitude of the AC waveform as shown in Figure 2-3. For each
Z-tooth type, the top row shows the physical teeth, the middle row shows the
simplified AC waveform, and the bottom row shows the digital output signal. The
index tooth determines the position of the shaft (i.e., the VR interface resets the
count upon detecting the index tooth).
Figure 2-3 Z-Tooth Types

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2.1.2 Torque
Measurement
Torque measurements require two toothed wheels on the same shaft: one
toothed wheel is under torque and the other wheel is under zero torque. As the
shaft twists under torque, the two wheels become slightly misaligned. The VR
interface indirectly measures the degree offset by counting the time between
when a tooth on the leading wheel passes the sensor and when a tooth on the
lagging wheel passes the sensor. The torque pulse signal is shown in
Figure 2-4. This offset can be converted to torque from the shaft specification
(see Section 2.2.4.2).
Figure 2-4 Dual VR Sensor Torque Measurement
VR
1
VR
2
Torque
Pulse
VR
2
VR
1
Δt
Δt

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2.2 DNx-VR-608
Device
Architecture
A simplified block diagram of the DNx-VR-608 Variable Reluctance Interface
board is illustrated in Figure 2-5.
Figure 2-5 Simplified Block Diagram of the DNx-VR-608
2.2.1 Inputs The front-end of the DNx-VR-608 exposes eight differential analog inputs
through the DB-37 connector. The eight channels are grouped and isolated in
pairs (0&1, 2&3, 4&5, 6&7), where each pair can accept either two individual VR
sensors or one out-of-phase dual VR sensor. Revision 2 boards also provide
four TTL-level digital inputs which route directly to the counter timer modules.
The DNx-VR-608 is designed to accept the following input signal sources:
• AC waveform from a VR sensor - The VR sensor’s signal and return
wires connect to a single channel (e.g., In0+/- of Channel 0). The board
supports systems with or without a zero/index/z-tooth.
• AC waveforms from a dual VR system - The two VR sensors are
connected to a channel pair (e.g., one sensor on In0+/- of Channel 0 and
one on In1+/- of Channel 1). The board detects rotational direction
(“dirn”) by checking for the leading channel. Revision 2 boards can also
measure the phase shift between the two channels; this feature is used
to compute torque in setups where one toothed wheel is under torque
and the other is not.
FPGA
VR-608 Channel Pair 0/1
32-bit 66-MHz Bus
Boot/Store Flash
VR-608 Logic
Optical Isolation Boundary (Per Channel Pair)
PGA
PGA
ADC
DAC VTH1
Cube/Rack
Logic
PGA
DAC VTH0
PGA
ADC
In0+
In0-
In1+
In1-
Clip & Comparator 0
VR-608 Channel Pair 2/3
VR-608 Channel Pair 4/5
VR-608 Channel Pair 6/7
Input FIFO
DOut0
Ch 2/3, 4/5, 6/7 Logic
VR Sensor
Interface 1
Dual Sensor Interface
VR Sensor
Interface 0
-or-
DB-37 Connector
Sync 2
Sync 3
Sync 1
Sync 0
Clip & Comparator 1
ch1_volts
cout0
cout1
MAX 9926
Dual VR IC
Direction
Detector
ch0_volts
DIn0 <rev. 2>
<rev. 2>
dirn
CT Input Selector
Digital Output
Selector
ttl_in
ADC ZC Detector
ADC ZC Detector
FIR
<rev. 2>
Counter/
Timer 0
Counter/
Timer 1
FIR
<rev. 2>

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• TTL-level digital pulse train - Some sensors, such as Hall Effect
sensors, already output a conditioned 0-5 V square wave.
• Revision 1: The digital sensor’s signal and return wires connect to
a single VR-608 channel (e.g., In0+/- of Channel 0); the sensor’s
power wire does not connect to the VR-608.
• Revision 2: The digital sensor can either connect to a VR-608
channel or connect directly to a counter/timer module through DIn/
DIGnd. The direct DIn connection is the recommended configuration
as it bypasses the zero crossing and peak threshold stages for a
faster read rate.
2.2.1.1 Input
Conditioning
All VR analog inputs pass through a limiter circuit before entering the Dual VR
IC and ADCs.
Revision 2 boards provide a digital FIR filter after each ADC to smooth out noise
on the VR inputs. It is useful when the ADC tooth rate is greater than 10 kHz. By
default, the FIR filter is disabled. It may be enabled in board configuration.
2.2.2 Zero Crossing
Detection
Zero crossing detection is performed by either the Dual VR IC (default) or the
channel’s ADC. The ADC input path is highlighted in blue in Figure 2-5.
The DNx-VR-608 supports the following zero crossing modes:
•VR608_ZC_ONCHIP: automatically determines the mid-range of the
analog sine wave signal using the built-in zero-cross detector of the
Dual VR IC.
•VR608_ZC_FIXED: fixed to a particular voltage level by the user and
detected by the ADC module. If the desired zero crossing level is 0 V,
UEI recommends setting the desired zero crossing level to a value
slightly above 0 to avoid false positives, e.g., 0.1 V.
•VR608_ZC_LOGIC: calculated by the ADC module as (min+max)/2,
subject to a configurable moving average.
Because the Dual VR IC expects a bipolar input, Hall Effect sensors and other
unipolar digital inputs should use an ADC-based mode (ZC_FIXED OR
ZC_LOGIC). ADC-based modes cap the input pulse rate at 18 kHz.
DIn connections will use VR608_ZC_ONCHIP by default. This is the
recommended configuration. Using VR608_ZC_ONCHIP mode is also
recommended with analog inputs.
2.2.2.1 Dual VR IC The Dual VR IC’s purpose is to convert the VR sensor’s analog signal into a
digital output. The Dual VR IC electronic chip is the Maxim MAX9926 Variable
Reluctance Sensor Interface.
Figure 2-6 takes a closer look at the logic for one channel in the Dual VR IC.
After the input signal has passed the limiter circuit, it enters the Dual VR IC and
is clipped from ±125 V down to ±5 V using Zener diodes. The ±5 V input is
amplified before entering the zero crossing detection circuit.
The zero crossing circuit centers around an inverting comparator. The
reference voltage at the comparator’s non-inverting (+) terminal switches
between the zero crossing level and a configurable peak threshold level
depending on the current state of the comparator output (cout). When cout is
low, the input is compared to the zero crossing level to determine when cout
should be raised. When cout is high, the input is compared to the peak

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threshold to determine when cout should be dropped. The peak threshold
allows the comparator to ignore zero crossings due to noise. The resulting
digital output signal is illustrated in Figure 2-2.
Figure 2-6 Logic Block Diagram for a Dual VR IC Channel
2.2.2.2 Peak
Threshold
Levels
Setting a peak threshold level introduces hysteresis to the zero crossing
detector. The DNx-VR-608 provides the following peak threshold
configurations:
•VR608_APT_ONCHIP: automatically adjusts the threshold to 1/3 of the
peak of the previous analog input cycle, using the built-in APT detector
of the Dual VR IC (see Figure 2-7). Note that if the input voltage
remains lower than the adaptive threshold for 85 ms, the threshold will
be dropped to the chip’s minimum value, driving the comparator output
low; this ensures pulse recognition in the presence of an intermittent
sensor connection.
•VR608_APT_LOGIC: calculated as (max)/2^n, where n=1, 2, 3, or 4
and “max” is the moving average of previous analog input peaks (Rev. 2
only).
Figure 2-7 Adaptive Peak Threshold (APT) from the MAX9926
Specification
1/3
2RX/1TX ARINC-429 transceiver protocol controllers (FPGA/DSP control/access Block 1)2RX/1TX ARINC-429 transceiver protocol controllers (FPGA/DSP control/access Block 1)
In0-
In0+
VR Sensor
Interface 0
DB-37 Connector
Limiter
Circuit
Clipper
Circuit Amplifier
Comparator
-
+
-
+
FIXED or LOGIC peak
threshold from DAC
ONCHIP zero
crossing level
MAX 9926 Channel 0
VR-608 Logic
cout0
Input Voltage
Peak Detector
ONCHIP peak
threshold
20ms
V1
40ms 60ms
COUT
VR
SIGNAL
ADAPTIVE
THRESHOLD
SET BY V1
ADAPTIVE
THRESHOLD
SET BY V2 MIN
THRESHOLD
80ms 100ms 120ms 140ms 160ms
85ms
V1
1
3V2
1/3 V2
180ms 200ms