Polhemus VIPER 4 User manual

Rev. A May 2020
®
USER MANUAL
FOR MODELS
VIPER 4
VIPER 8
VIPER 16
URM18PH392
May 2020 Rev. A

USER MANUAL
Rev. A 2 May 2020
Copyright © 2020 by Alken, Inc. dba Polhemus
Colchester, Vermont, U.S.A.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in
any form or by any means, mechanical, photocopying, recording or otherwise, without the prior written
permission of Polhemus. No patent liability is assumed with respect to the use of the information contained
herein. While every precaution has been taken in the preparation of this manual, Polhemus assumes no
responsibility for errors or omissions. Neither is any liability assumed for damages resulting from use of the
information contained herein.
Windows® is a registered trademark of Microsoft Corporation.
Linux® is the registered trademark of Linus Torvalds in the U.S. and other countries.
Medical Device Use
The VIPER™products are certified to meet the EN60601 conformance standards as noted in the following
sections. If VIPER™ products are used in a medical setting it is intended that they are used as medical device
components. Medical device components are products integrated into other medical devices or medical device
systems.
The VIPER™system does not have a specific indication for use and there are no stand-alone regulatory clearances
or approvals for the VIPER™itself.
As defined by FDA (21 CFR 820.3(c)), a component is any raw material, substance, piece, part, software, firmware,
labeling, or assembly that is intended to be included as part of the finished, packaged, and labeled device.
The end user/OEM/VAR/Distributor must determine how the VIPER™products will be used and comply with all
FDA/CE regulations pertaining to the development and sale of finished medical devices and all other regulatory
requirements.

USER MANUAL
Rev. A 3 May 2020
FCC Statement
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part
15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not
installed and used in accordance with the instructions, may cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which can be determined by turning the equipment
off and on, the user is encouraged to try to correct the interference by one or more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
- Consult the dealer or an experienced radio/TV technician for help.
EMC/EMI:
IEC 60601-1-2 Medical Electrical Equipment, Edition 4.0
Immunity Requirements:
EN61000-4-2:2009 Electrostatic Discharge
EN61000-4-3:2005/A1:2008/A2:2010 Radiated Immunity
EN61000-4-4:2004/A1:2010 EFT/Burst Power Leads
EN61004-5:2006 Surge Immunity
EN61000-4-6:2009 Conducted Immunity, Power Leads
EN61000-4-8:2010 Power Frequency Magnetic Fields
EN61000-4-11: 2004 Voltage Dips and Interrupts
Note: The conducted emission herein only applies if a Polhemus-supplied power supply is used with the VIPER™
unit.
Electrical Safety Approvals
IEC 60601-1 Medical Electrical Equipment, Edition 3.1
Classifications
Electric Shock Protection
Class I - protectively earthed with power from supply mains
Shock Protection Degree
Sensors and TX-1 Source = BF / TX2 and TX4 Sources = B
Ingress Protection
Sensors and TX-1 Source = IP67 TX2 and TX4 Sources = IPX0 (see Section 7)
Sterilization
Sensors and TX1 = ethylene oxide gas
Flammability
Not intended for use in a flammable or oxygen rich atmosphere
Mode of Operation
Continuous

USER MANUAL
Rev. A 4 May 2020
HOW TO USE THIS MANUAL
This user manual serves as a reference guide for the setup and operation of the Polhemus VIPER™tracker.
To quickly set up and run a new VIPER™system, refer to Section 3. GETTING STARTED. This section offers a step-
by-step approach to guide you in installing, configuring and running your device in a simplified scenario of one
Source and one Sensor.
The manual is divided into several parts:
Section 1. VIPER™SYSTEM OVERVIEW provides detailed descriptions and physical information about the
hardware and software components and accessories that make up the VIPER™ system.
Section 2. OPERATION provides general description of how the tracker can be deployed and some advice on
physical installation.
Section 3. GETTING STARTED is a detailed step-by-step guide to installation, setup and simple operation of a
minimal system. This section is designed to familiarize you with the basic process of setting up a system without
delving into details of larger or more complex installations.
Section 4. VIPER™ COMMAND INTERFACE lists the different commands for controlling VIPER™and describes
their functions.
Section 5. PRECAUTIONS Outlines precautions to observe when using VIPER™.
Section 6. BIT ERRORS provides a list of the system errors and their meanings.
Section 7. EXPLANATION OF SYMBOLS provides an explanation of symbols used in this manual.
Appendix A. Terms & Acronyms is a good resource for terms used commonly throughout the manual. Follow
red definition hyperlinks placed in each section to read the term definition in Appendix A. If reading with a PDF
reader: After following a definition link, hold down the Alt key plus the left arrow on your keyboard to return to
your place in the manual.
Throughout the manual, look for the following symbols for background information, helpful tips and cautionary
notes:
More Information.
Helpful tip.
Caution, Warning, or Safety Note.

USER MANUAL
Rev. A 5 May 2020
SAFETY NOTICES
This apparatus has been designed and tested in accordance with EN60601-1, 3rd edition.
Before powering up the instrument, be aware that the main plug shall only be inserted in a socket outlet
provided with a protective ground contact. You must not negate the protective action by using an extension
cord (power cable) without a protective conductor (grounding). Grounding one conductor of a two-
conductor outlet is not sufficient protection.
The VIPER™ sensors and sensor ports use standard USB-C style connectors. These ports are NOT a USB
connection. Only plug a VIPER™sensor/stylus into these sensor ports.
When connecting a host device to the VIPER™ USB or RS-422 output port, ensure that the host device is
compliant to the relevant safety standard for that device (EN60950/EN61010).
Only connect a Polhemus magnetic source into the source ports.
Do not operate the instrument in the presence of flammable gases or fumes. Operation of any electrical
instrument in such an environment constitutes a definite safety hazard.
Only use the sync port with a Polhemus provided sync cable and in accordance with the instructions in this
manual.
Do not connect two magnetic sources of the same frequency. The SEU will cease operation.
Be sure to read and understand the concept of Hemisphere of Operation in this manual and operate the
product using the correct Hemisphere of Operation setting.
Be sure to read and understand the setup and operation of this product to ensure accurate measurements.
Read the Precautions section of this manual.
WARNINGS
This instrument contains no user serviceable parts. Do not attempt to service the unit. Return it to Polhemus
for repair.
Do not perform any unauthorized modification to the instrument.
Do not use the instrument in a manner not specified by the manufacturer.
Only use the DC power supply provided by Polhemus: part number 1C0614.
Ensure the VIPER™ power supply or power cord to the power supply is accessible so mains power can be
removed quickly.
CONTRAINDICATIONS
There are no contraindications with the VIPER™ system as provided by Polhemus. The final medical product that
the VIPER™ system is incorporated into needs to be evaluated for contraindications.

USER MANUAL
Rev. A 6 May 2020
CLEANING
The only required maintenance is cleaning the System Electronics Unit (SEU), Sources, Sensors and Cables. If the
instrument requires cleaning:
1. Remove power from the SEU.
2. Clean the external surfaces of the SEU, Cables and external shells of the Sources and Sensors with a soft
cloth dampened with a mixture of mild detergent and water.
Make sure that the SEU is completely dry before reconnecting it to a power source.
STERILIZATION
No component of VIPER™ is provided sterilized. Only the sensors and TX1 Source can be sterilized and only with
ETO Gas. There is no known limit on the number of cycles.
STORAGE AND TRANSPORT
Temperature -10C to +50C
Relative Humidity 10% to 90% non-condensing
Atmospheric Pressure 50kPa to 106kPa
DISPOSAL
VIPER™ components are considered electronic waste and should be disposed of in accordance with local
ordinances.

USER MANUAL
Rev. A 7 May 2020
SPECIFICATION
Update Rate (per Sensor, simultaneous samples)
VIPER™4 - 240Hz, VIPER™8 and VIPER™up to 960Hz. (30, 60, 120, 240, 480 or 960Hz).
Latency
960Hz –1 millisecond. 480Hz –2 milliseconds. 240Hz –3.5 milliseconds.
Number of Sensor Inputs
VIPER™4: 1 to 4; VIPER™8: 1 to 8; VIPER™16: 1 to 16.
Number of Source Inputs
VIPER™4: 1; VIPER™8: 2; VIPER™16: 4.
I/O Ports
USB 2.0; RS422 tested to 921,600. (Possible to program baud rate to 7,372,800).
Static Accuracy
0.015 in. RMS for X, Y or Z position; 0.10° RMS for Sensor orientation (magnetically clean
environment, FTT® turned off).
Resolution
0.00004 in. (0.0010 mm) at 12 in. (30 cm) range; 0.0003° orientation.
Range
30 in. (76 cm) radius from Source at above specifications with TX2. Useful operation in excess of
72 in. (182 cm) in radius with one Source. Using multiple Sources extends tracking range further.
Multiple Systems
Provisions available to operate multiple systems in same environment.
Angular Coverage
All-attitude.
Data Format
IEEE 754 binary.
External Sync
Configurable port for either input or output. (See Section 2.3.)
Physical Characteristics
See Appendix C.
Power Requirements
5 Volt 8 amps max; 100-240VAC and 50-60Hz.
Operating Temperature
10°C-40°C at a relative humidity of 10% to 90% non-condensing.
Operating Environment
SEU/TX2/TX4: Rated IPX0. Not protected against the ingress of water or dust. Operate, store
and transport in a dry environment.
TX1/Sensors: Rated IP67. May be submerged in freshwater up to 1 meter for up to 30 minutes.
Dust-tight.
Atmospheric Pressure 50kPa to 106kPa.

USER MANUAL
Rev. A 8 May 2020

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TABLE OF CONTENTS
How To Use This Manual ....................................................................................................................................... 4
Specification .......................................................................................................................................................... 7
Table of Contents................................................................................................................................................... 9
List of Figures....................................................................................................................................................... 11
1. VIPER™ SYSTEM OVERVIEW ................................................................................................................... 13
1.1 INTRODUCTION....................................................................................................................................13
1.1.1 HOW VIPER™ MOTION TRACKING WORKS ............................................................................................13
1.2 VIPER™ SYSTEM COMPONENTS..............................................................................................................14
1.2.1 VIPER™ SEU..................................................................................................................................14
1.2.1.1 LED PATTERNS 15
1.2.2 SENSOR ..........................................................................................................................................16
1.2.3 STYLUS ...........................................................................................................................................17
1.2.4 SOURCE..........................................................................................................................................17
2. OPERATION............................................................................................................................................ 19
2.1 FTT® MODE........................................................................................................................................19
2.2 I/O CONSIDERATIONS ...........................................................................................................................20
2.3 EXTERNAL SYNC ...................................................................................................................................21
2.4 SOFT RESET ........................................................................................................................................21
3. GETTING STARTED.................................................................................................................................. 23
3.1 SETTING UP VIPER™ HARDWARE FOR THE FIRST TIME.................................................................................23
3.1.1 MAKE CONNECTIONS.........................................................................................................................23
3.1.2 PLACE SOURCE AND SENSOR(S)............................................................................................................23
3.2 INSTALL HOST SOFTWARE (WINDOWS®)...................................................................................................24
3.3 RUN VIPER™ COMMAND MANAGER .......................................................................................................25
3.3.1 UPDATE VIPER™ COMMAND MANAGER...............................................................................................25
3.4 VIPER™ COMMAND MANAGER USER INTERFACE OVERVIEW.........................................................................26
3.4.1 DISPLAYING VIPER™P&O DATA .........................................................................................................27
3.4.2 CONFIGURING VIPER™.....................................................................................................................28
3.4.2.1 COMMONLY USED SETTINGS 28
3.4.2.2 ADVANCED SETTINGS 29
3.4.2.3 PERSISTENCE 30
3.4.3 KEYBOARD SHORTCUTS ......................................................................................................................30
3.5 CONFIGURING VIPER™ MULTI-SOURCE MODES OF OPERATION.....................................................................31
3.5.1 SINGLE-SOURCE MODE ......................................................................................................................31
3.5.2 DUAL-SOURCE MODE ........................................................................................................................31
3.5.3 LOCAL-SOURCE MODE .......................................................................................................................31
3.5.3.1 NEAREST SOURCE 32
3.5.4 CUSTOM MULTI-SOURCE MODE CONFIGURATION ....................................................................................33
3.5.5 EXPANDED TRACKING AREA MULTI-SOURCE MODE...................................................................................33
3.6 USING A STYLUS WITH VIPER™ ..............................................................................................................34
4. VIPER™ COMMAND INTERFACE ............................................................................................................. 35
4.1 COMMAND SUMMARY ..........................................................................................................................35
4.2 CONFIGURATION COMMANDS,PERSISTENT ...............................................................................................37
4.2.1 FRAME RATE COMMAND ................................................................................................................37

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4.2.2 UNITS COMMAND ...........................................................................................................................37
4.2.3 SYNC MODE COMMAND .................................................................................................................38
4.2.4 STYLUS MODE COMMAND ..............................................................................................................38
4.2.5 SEU ID COMMAND...........................................................................................................................39
4.2.6 SOURCE ROTATION COMMAND ......................................................................................................39
4.2.7 SOURCE CONFIGURATION COMMAND ...........................................................................................40
4.2.8 PREDICTION FILTER COMMAND ......................................................................................................42
4.2.9 HEMISPHERE COMMAND................................................................................................................42
4.2.10 FILTER COMMAND...........................................................................................................................43
4.2.11 INCREMENT COMMAND .................................................................................................................46
4.2.12 FTT MODE COMMAND ....................................................................................................................46
4.2.13 VIRTUAL SENSOR COMMAND..........................................................................................................47
4.2.14 SOURCE CONFIGURATIONS AND MODES OF OPERATION ...........................................................49
4.2.14.1 SOURCE SELECT COMMAND 49
4.2.14.2 SENSOR ORIGIN COMMAND 50
4.3 CONFIGURATION COMMANDS,NOT-PERSISTENT........................................................................................52
4.3.1 RS-422 SERIAL PORT CONFIGURATION COMMAND ........................................................................52
4.3.2 DUAL OUTPUT MODE COMMAND...................................................................................................53
4.3.3 TIP OFFSET COMMAND ...................................................................................................................53
4.3.4 BORESIGHT COMMAND ..................................................................................................................54
4.4 P&O COMMANDS................................................................................................................................55
4.4.1 STANDARD P&O FRAME ....................................................................................................................55
4.4.2 ALTERNATIVE P&O FRAME WITH ACCELERATION ....................................................................................56
4.4.3 SINGLE PNO COMMAND..................................................................................................................57
4.4.4 CONTINUOUS PNO COMMAND.......................................................................................................57
4.5 READ-ONLY COMMANDS ....................................................................................................................59
4.5.1 BIT RESULTS COMMAND .................................................................................................................59
4.5.2 STATION MAP COMMAND ..............................................................................................................59
4.5.3 DISTORTION MAP STATUS COMMAND ...........................................................................................59
4.5.4 WHO AM ICOMMAND ....................................................................................................................60
4.5.5 SENSOR WHO AM ICOMMAND.......................................................................................................60
4.5.6 SOURCE WHO AM ICOMMAND ......................................................................................................61
4.6 EXECUTIVE COMMANDS .....................................................................................................................62
4.6.1 PERSIST COMMAND ........................................................................................................................62
4.6.2 BLOCK CONFIG RESET COMMAND...................................................................................................62
4.6.3 ENABLE DISTORTION MAP COMMAND ...........................................................................................63
5. PRECAUTIONS ........................................................................................................................................ 64
6. BIT ERRORS ............................................................................................................................................ 65
7. EXPLANATION OF SYMBOLS ................................................................................................................... 66
APPENDIX A. TERMS & ACRONYMS......................................................................................................................67
APPENDIX B. SOURCE HEMISPHERES ...................................................................................................................75
APPENDIX C. SENSOR AND SOURCE DIMENSIONS ...............................................................................................77
APPENDIX D. LIMITED WARRANTY AND LIMITATION OF LIABILITY......................................................................85
APPENDIX E. CUSTOMER SERVICE........................................................................................................................86

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LIST OF FIGURES
FIGURE 1. VIPER™ SEU FRONT VIEW: VIPER™ 4, VIPER™ 8, VIPER™ 16 ...................................................................14
FIGURE 2. VIPER™ SEU REAR VIEW: VIPER™ 4/8, VIPER™ 16 ...................................................................................14
FIGURE 3. VIPER™ 8 SEU PANEL LEGEND..................................................................................................................14
FIGURE 4. VIPER™ SEU DIMENSIONS (APPROXIMATE), INCHES (CM) ......................................................................15
FIGURE 5. VIPER™ SENSORS. FROM TOP: FT-STANDARD, FT-FLATSIDED, AND FT-CLIP (WITH CLIP SHOWN) .........16
FIGURE 6. VIPER™ FT3-STYLUS AND FT8-STYLUS......................................................................................................17
FIGURE 7. VIPER™ TX2 SOURCE ................................................................................................................................18
FIGURE 8. PINOUT VIPER™ RS-422 MALE CONNECTOR............................................................................................20
FIGURE 9. VIPER™ EXTERNAL SYNC PINOUT.............................................................................................................21
FIGURE 10. GETTING STARTED: CONNECTIONS........................................................................................................23
FIGURE 11. SENSOR PLACED IN +X HEMISPHERE......................................................................................................24
FIGURE 12. SEU AND SENSOR BLOCK CONFIGURATION PANELS..............................................................................29
FIGURE 13. VIPER™ 16 SINGLE-SOURCE MODE ........................................................................................................31
FIGURE 14. VIPER™ 16 DUAL-SOURCE MODE...........................................................................................................31
FIGURE 15. VIPER™ 8 LOCAL SOURCE LOCATIONS ...................................................................................................31
FIGURE 16. VIPER™ 16 LOCAL SOURCE LOCATIONS .................................................................................................32
FIGURE 17. VIPER™ 16 NEAREST SOURCE, EXAMPLE A ............................................................................................32
FIGURE 18. VIPER™ 16 NEAREST SOURCE, EXAMPLE B ............................................................................................32
FIGURE 19. VIPER™ 16 NEAREST SOURCE, EXAMPLE C ............................................................................................32
FIGURE 20. LOCAL SENSOR GROUPS.........................................................................................................................47
FIGURE 21. VIRTUAL SENSOR EXAMPLE ...................................................................................................................48
FIGURE 22. SOURCE HEMISPHERES ..........................................................................................................................75
FIGURE 23. OUTLINE DIMENSIONS (APPROX.), VIPER™ FT-STANDARD SENSOR......................................................77
FIGURE 24. OUTLINE DIMENSIONS (APPROX.), VIPER™ FT-FLATSIDED SENSOR ......................................................78
FIGURE 25. OUTLINE DIMENSIONS (APPROX.), VIPER™ FT-CLIP SENSOR.................................................................79

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FIGURE 26. OUTLINE DIMENSIONS (APPROX.), VIPER™ FT SENSOR CLIP .................................................................80
FIGURE 27. OUTLINE DIMENSIONS (APPROX.), TX2 STANDARD SOURCE.................................................................81
FIGURE 28. OUTLINE DIMENSIONS (APPROX.), TX4 SOURCE ...................................................................................82
FIGURE 29. OUTLINE DIMENSIONS (APPROX.), VIPER™ HR SOURCE........................................................................83

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1. VIPER™SYSTEM OVERVIEW
Congratulations on your purchase of VIPER™, the latest generation of Polhemus Tracking Systems. The VIPER™
design has several new innovations. These innovations include FTT® (Fly True Technology) –a new technology
that adds real-time eddy current distortion mitigation, up to four magnetic sources in a single System Electronics
Unit (SEU), and faster update rates as high as 960Hz.
VIPER™ is available in three different models: VIPER™4, VIPER™8, and VIPER™16.
1.1 INTRODUCTION
The Polhemus VIPER™ is an electromagnetic tracking system based on a scalable architecture that supports up to
16 Sensors and 4 Sources in a single chassis.
The flexible VIPER™ design offers unprecedented versatility and scalability for the Polhemus motion tracking
user.
HOW VIPER™ MOTION TRACKING WORKS1.1.1
An electromagnetic (EM) field is emitted from one or more Sources. Sensors detect the emitted field(s) and the
System Electronics Unit (SEU) calculates Position and Orientation (P&O) of each of the Sensors. The P&O data is
streamed from the SEU via USB or RS-422 to a connected host computer.
On a Windows® host PC the VIPER™ Command Manager app (VPcmdMgr) may be used to visualize the motion of
the Sensors. Open-source programming libraries and sample programs are available for developing custom
applications that use the Sensor P&O data on Windows® or other computer operating system platforms.
The VIPER™ system operation is configured and controlled by an open source command interface. VIPER™
commands are applied to the system via the VPcmdMgr or via custom end-user software. The VIPER™ command
set is explained in detail in Section 4. of this user manual. VPcmdMgr users and software developers will find
explanations of the available commands in online help and useful tips and information displayed on the
VPcmdMgr display.
VIPER™ system hardware components are precisely calibrated at the factory using NIST (National Institute of
Standards and Technology) traceable fixturing. Recalibration of the system is never required.

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1.2 VIPER™SYSTEM COMPONENTS
The VIPER™System consists of a System Electronic Unit (SEU), one to sixteen Sensors and one to four
electromagnetic (EM) Sources. Communication with the system is via USB 2.0 or RS-422. The system only
requires 5 volt power. Host computer apps, programming libraries, and documentation are installed via web
download or thumb drive.
VIPER™SEU1.2.1
The VIPER™ SEU comes in three variations:
The VIPER™4 system supports one EM Source and up to four Sensors.
The VIPER™8 system supports up to two EM Sources and up to eight Sensors.
The VIPER™16 system supports up to four EM Sources and up to sixteen Sensors.
Figure 3 below identifies controls and ports on a VIPER™8 chassis.
Figure 4 below details approximate VIPER™ SEU dimensions. Note that all SEUs have the same footprint. Rubber
feet add approximately 0.2 inches (0.51 cm) to the height.
FIGURE 1. VIPER™ SEU FRONT VIEW: VIPER™4, VIPER™8, VIPER™16
FIGURE 2. VIPER™ SEU REAR VIEW: VIPER™4/8, VIPER™16
FIGURE 3. VIPER™ 8 SEU PANEL LEGEND

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1.2.1.1 LED PATTERNS
Startup sequence:
1. All SEU LEDs turn red for approximately 2 seconds, and then flash green once.
2. Each sensor board will flash a blue LED pattern corresponding to detected Source frequency:
a. Sensor Ports 1, 2, 3, or 4 will flash blue:
ONCE for corresponding Source frequency 1-4.
For example, Source Frequency 1 will cause sensor port 1 LED to flash blue ONCE during
startup sequence, Source Frequency 2 will cause port 2 to flash blue ONCE, etc.
TWICE for Source frequencies 5-8, and so on.
For example, Source Frequency 5 will cause sensor port 1 LED to flash blue TWICE during
startup sequence, Source Frequency 6 will cause port 2 to flash blue TWICE, etc.
b. All four LEDs on the board will flash red if no source is detected.
3. Sequentially, each sensor port LED will flash once:
Green if a sensor is detected, or
Red if no sensor is detected.
4. All LEDs turn OFF (dark) as the boot process completes.
Runtime Sensor port LEDs:
Green:
Sensor Active
Red:
Sensor Inactive or out of range.
Blue:
Sensor FTT® is engaged. (Requires FTT® mode to be enabled. See Section 2.1.)
Alternating Green/Blue:
Sensor FTT® is on but not engaged until sensor is “Homed.” (See Section 2.1.)
Sensor board LEDs blink red:
Duplicate source frequencies detected on blinking sensor boards; tracker
cannot start.
FIGURE 4. VIPER™ SEU DIMENSIONS (APPROXIMATE), INCHES (CM)

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SENSOR1.2.2
Position and Orientation (P&O) is calculated at the EM center of the Sensor device, relative to a Cartesian origin
location in the motion tracking area. By default, this reference location is at the EM center of a VIPER™ Source,
so all calculated Sensor P&O is relative to that Source. Alternatively, the reference location may be defined by
the user, selected for the specific needs of the application. Refer to Sections 3.5 “Configuring VIPER™ multi-
source modes of operation“and 4.2.14 “SOURCE CONFIGURATIONS AND MODES OF OPERATION“ for details
about this.
The VIPER™ Sensor is available in multiple styles, including:
FT-Standard: with mounting holes
FT-Flatsided: without mounting holes
FT-Clip: with tapered edges that fit into a mounting clip
The Sensors connect easily to the SEU via reversible plugs so the orientation of the connector does not matter
when plugging in.
See Appendix C for Sensor dimensions.
FIGURE 5. VIPER™ SENSORS. FROM TOP: FT-STANDARD, FT-FLATSIDED, AND FT-CLIP (WITH CLIP SHOWN)

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STYLUS1.2.3
The Stylus is a pen-shaped device that is tracked positionally in three dimensions as well as angularly. A push
button switch is integrated to give the user control of the data output. Stylus position measurements are
calculated at the tip of the Stylus, using precise factory calibration. The tip is removable/replaceable and
available with a sharp point (standard) tip or a rounded tip. The Stylus is available in two sizes: 3 inches long
(FT3-Stylus) and 8 inches long (FT8-Stylus).
SOURCE1.2.4
The VIPER™ Source emits the electromagnetic field (EM field) necessary to track the P&O of Sensors within
range. The three-dimensional space in which the EM field is detectable by the Sensors is known as the motion
tracking area. Multiple Sources may be used to define and expand this area. When more than one Source is
used, each Source must operate at a different frequency so that it can be distinguished from the others by the
Sensors. (Source frequency is not a configurable feature; Sources are manufactured to operate at specific
frequencies and may be purchased accordingly.)
In a standard installation, the Source is usually the reference for Sensor P&O measurements. The Source is
powered by the SEU and is connected at the dedicated Source connection port(s). Up to four sources can be used
in a single VIPER™ system.
The Source is usually mounted in a fixed position to a non-metallic surface or stand located in close proximity to
the Sensors.
VIPER™ Sources are available in a variety of form factors and EM frequencies. The standard TX2 Source is a 2-inch
cube. Other sizes available include TX4 (a 4-inch cube) and several smaller sizes, including the HR-Source. The
larger sized Sources emit a stronger field that can be detected from farther away by the standard Sensors. The
smaller sized Sources have a proportionally weaker field and are useful where close proximity and smaller form
factor are needed. Specifications in this manual are based on the standard 2-inch Source.
See Appendix C for approximate Source dimensions.
FIGURE 6. VIPER™ FT3-STYLUS AND FT8-STYLUS

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FIGURE 7. VIPER™ TX2 SOURCE

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2. OPERATION
With the ability to drive multiple Sources and sixteen Sensors, VIPER™ can be operated in many configurations.
Modes of operation can be configured on a per-Sensor basis. Typical modes of operation are described below.
Standard Single-Source operation: A single Source is used. All Sensor position and orientation (P&O) is referenced
to that one Source. On a VIPER™8 or VIPER™16 system, the one Source must be connected to Source port 1.
This is the traditional way that most legacy Polhemus trackers operate.
Standard Multi-Source modes of operation: Two, three, or four Sources of differing frequencies are used on a
VIPER™8 or VIPER™16 system. Each Sensor P&O is referenced to the nearest connected Source. In this mode,
one VIPER™ system can effectively behave as the equivalent of up to four individual and independent
conventional tracking systems. This is a new and unique capability of VIPER™ over earlier tracking systems. These
modes of operation are discussed in detail in Section 3.5.
Expanded Multi-Source operation: Multiple Sources are configured together to define an expanded tracking
area. By default, each Sensor operates with all Sources. If desired, each Sensor may be configured to operate
with any combination of Sources.
VIPER™ Sensor and Source configuration commands allow the user to configure and modify these basic modes of
operation. These commands and modes of operation are discussed in detail in Sections 3.5 and 4.2.13 below.
2.1 FTT® MODE
FTT® (Fly True Technology) is a revolutionary real-time magnetic distortion mitigation method exclusive to
Polhemus. The benefits are most noticeable in a tracking environment with electromagnetic distorting
conditions, namely the presence of certain conductive metals that support magnetic eddy currents. These
conditions, when in proximity to the Sensor or Source can cause errors in the position and orientation outputs
from the VIPER™tracking system until removed.
HOW IT WORKS:
FTT® Mode is an iterative filter that uses measured magnetic fields emitted from the VIPER™Source, known
environmental conditions, and electromagnetic hemispheric frequencies detected by the FT Sensor to recognize
the negative influence of magnetic distortion and apply a real-time filtered correction. The resulting tracking
performance can be stunningly good in environmental conditions that might otherwise limit the utility of the
tracker (examples include tracking near large metal objects like desks, filing cabinets, steel walls, and rebar
concrete floors).
To use FTT®, the VIPER™tracker must have FTT® Mode enabled and the FT Sensor in a “Home” location near a
Source. When FTT® is enabled in this way, the LED light for the FT Sensor port in use on the VIPER™SEU (System
Electronics Unit) will be green in color. The LED will blink in a green and blue pattern until “Homing” has
occurred.
As the FT Sensor is moved away from the Source or a distortion-inducing object is brought close to the FT Sensor
or Source, FTT® will engage and the LED light for the FT Sensor port in use will turn blue. FTT® is now actively
working to sense the electromagnetic distortion and apply a correction filter in real-time to the Position and
Orientation tracking output. FTT® corrects for both position and orientation data output.

USER MANUAL
Page 20 of 86 URM18PH392 Rev A. May 2020
FTT® should start with the Sensor in “Home” location and with the FT-Sensor’s
SEU Sensor port in a GREEN LED state. The Sensor port LED will alternate
GREEN and BLUE until Sensor is “Homed” this way.
At introduction, VIPER™ FTT® has two modes of operation: Stationary Source Mode for conventional tracking
applications where VIPER™ Sources are mounted in a fixed position and Moving Source Mode where VIPER™
Sources may be used in innovative dynamic and diverse scenarios. Be sure to understand the difference
between the modes and select the best one for your tracking applications. Refer to Section 4.2.12 FTT MODE
command for details about the available FTT® modes.
Both FTT® modes will “carry” the high-quality tracking performance of the VIPER™tracker in difficult conditions
for a period of time but due to the iterative nature of the filter, it is necessary to periodically return the FT Sensor
to Home in order to effectively reset the tracker’s measurement quality factors.
FTT® is a real-time distortion mitigation correction.
Due to the iterative nature of this feature, FTT® can cause tracking output to
be less precise in magnetically benign tracking environments than without it.
FTT® is a solution to a problem, but if no problem is present, it may be best
not to engage at all so that tracking solution variables are minimized. Users
may decide to leave FTT® Mode OFF in many situations depending upon
tracking quality needs.
2.2 I/OCONSIDERATIONS
VIPER™ has two communication I/O ports: USB and RS-422. The USB port uses a micro USB connector. The RS-
422 port uses a Micro D 9-pin plug connector (male, Molex part number 836119006). The pinout is shown in
Figure 8 below.
Either I/O port can be used for command input and data output. When the VIPER™ is powered ON, either port
will respond to commands when used as a single output port.
VIPER™ also supports a dual-output mode where the tracker data stream is output to both ports. In this mode, it
is recommended that the USB port be used for command input (as well as data output) and the RS-422 port be
monitored only for output data.
FIGURE 8. PINOUT VIPER™ RS-422 MALE CONNECTOR
Micro D 9-pin Plug, Molex part 83611-9006
1
TX+
6
TX-
2
7
Reset
3
8
4
RX+
9
RX-
5
GND