MTS SWIFT 20 User Manual

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SWIFT® 20 (Ultra) Sensor Product Information

Spinning Wheel Integrated Force Transducer For Small or High Performance Vehicles

100-037-800 L

Trademark information MTS, SWIFT, T estSt ar , and TestWare are registered trademarks of MTS Systems

Corporation within the United States. These trademarks may be protected in other countries.

Microsoft, Windows, Wi ndows for Workgroups, Windows 95, and Windows NT are registered trademarks of Microsoft Corporation. Apple and Macintosh are registered trademarks of Apple Computer, Inc. UNIX is a registered trademark of The Open Group. LabVIEW is a registered trademark of National Instruments Corporation. All other trademarks or service marks are property of their respective owners.

Publication information

Manual Part Number Publication Date

151956-00 B February 1999 100-037-800 A 12 June 2000 100-037-800 B 17 July 2000 100-037-800 C 9 May 2001 100-037-800 D December 2004 100-037-800 E February 2005 100-037-800 F April 2005 100-037-800 G May 2005 100-037-800 H October 2005

100-037-800 J January 2006 100-037-800 K November 2008 100-037-800 L December 2011

Contents

Technical Support 7

How to Get Technical Support 7 Before You Contact MTS 7 If You Contact MTS by Phone 9 Problem Submittal Form in MTS Manuals 10

Preface 11

Before You Begin 11

Conventions 12

Documentation Conventions 12

Hardware Overview 15

Spinning Applications (Test Track) 16

Non-spinning Applications (Simulation Lab) 17

Construction 18

Design Features 22

Coordinate System 23

Specifications 25

Calibration 29

Low-Profile Transducer Interface 31

Low-Profile TI Front Panel 34

Low-Profile TI Rear Panel 41

Induction Power Source 42

Low-Profile TI Jumpers 43

Interfacing with RPC 44

Software Utilities 45

Introduction 46

TISTATUS - Low-Profile Transducer Interface Status 47

TIXFER - Low-Profile Transducer Interface Transfer 48

TISHUNT - Low-Profile Transducer Interface Shunt 51

Setting Up Shunt Calibration Reference Values 55

TISETZERO – Low-Profile Transducer Interface Set Zero Method 56

SWIFT 20 Sensors Contents

Error Messages 57

Shunt Error Status 58

Setting up the Low-Profile Transducer Interface 59

Select a Zero Method 60

Calibration File Elements 61

Upload the Calibration File 64

Edit the Calibration File 66

Download the Calibration File 70

Installing the Transducer 73

Transducers Designed to Operate with a Low-Profile TI but Using a Mini TI 73

Test Track Vehicle for Slip Ring Sensor 74

Attaching SWIFT Components to the Wheel Assembly 77

Attaching SWIFT and Wheel Assembly to the Vehicle 80

Installing the Low-Profile Transducer Interface Electronics 82

Setting up the SWIFT Sensor for Data Collection 85

Verifying the Quality of the Zero Procedure 95

Collecting Data 98

Road Simulator 100

Attaching SWIFT Components to the Fixturing 102

Zeroing the Low-Profile Transducer Interface 105

Communication Configurations 106

Cable Configurations 108

SWIFT TI to PC Host (9-pin) 108 SWIFT Low-Profile TI to PC Host (25-pin) 108 SWIFT Low-Profile TI to SWIFT Low-Profile TI 109 T ermination Jumper 110

Analyzing SWIFT Data 111

The Data 112

Fx Data (Longitudinal Force) 113

Fz Data (Vertical Force) 115

Mx Data (Overturning Moment) 116

My Data (Brake Moment) 119

Acceleration and Braking Events Example 120

Slalom Curve Driving Example 122

Contents

SWIFT 20 Sensors

Maintenance 123

Transducer 124

Low-Profile Transducer Interface 125

Cables 126

Troubleshooting 127

Assembly Drawings 141

Cable Drawings 142

SWIFT 20A Mechanical Parts 156

SWIFT 20T Mechanical Parts 163

Common Parts 170

SWIFT 20 Sensors Contents

Contents

SWIFT 20 Sensors

Technical Support

How to Get Technical Support

Start with your

manuals

Technical support

methods

MTS web site

www.mts.com

E-mail techsupport@mts.com

Telephone MTS Call Center 800-328-2255

Fax 952-937-4515

Technical support

outside the U.S.

The manuals supplied by MTS provide most of the information you need to use and maintain your equipment. If your equipment includes MTS software, look for online help and README files that contain additional product inform ation.

If you cannot find answers to your technical questions from these sources, you can use the internet, e-mail, telephone, or fax to contact MTS for assistance.

MTS provides a full range of support services after your system is installed. If you have any questions about a system or product, contact MTS in one of the following ways.

The MTS web site gives you access to our technical support staff by means of a Technical Support link:

www.mts.com > Contact MTS > Service & Technical Support

Weekdays 7:00 A.M. to 5:00 P.M., Central Time

Please include “Technical Support” in the subject line.

For technical support outside the United States, contact your local sales and service office. For a list of worldwide sales and service locations and contact information, use the Global MTS link at the MTS web site:

www.mts.com > Global MTS > (choose your region in the right-hand column) > (choose the location closest to you)

Before You Contact MTS

MTS can help you more efficiently if you have the following information available when you contact us for support.

Know your site

number and system

number

SWIFT 20 Sensors Technical Support

The site number contains your company number and identifies your equipment type (material testing, simulation, and so forth). The number is usually written on a label on your MTS equipment before the system leaves MTS. If you do not have or do not know your MTS site number, contact your MTS sales engineer.

Example site number: 571167

When you have more than one MTS system, the system job number identifies which system you are calling about. You can find your job number in the papers sent to you when you ordered your system.

Example system number: US1.42460

Know information from

prior technical

If you have contacted MTS about this problem before, we can recall your file. You will need to tell us the:

assistance

• MTS notification number

• Name of the person who helped you

Identify the problem Describe the problem you are experiencing and know the answers to the

following questions:

• How long and how often has the problem been occurring?

• Can you reproduce the problem?

• Were any hardware or software changes made to the system before the

problem started?

• What are the model numbers of the suspect equipment?

• What model controller are you using (if applicable)?

• What test configuration are you using?

Know relevant

computer information

Know relevant

software information

If you are experiencing a computer problem, have the following information available:

• Manufacturer’s name and model number

• Operating software type and service patch information

• Amount of system memory

• Amount of free space on the hard drive in which the application resides

• Current status of hard-drive fragmentation

• Connection status to a corporate network

For software application problems, have the following information available:

• The software application’s name, version number, build number, and if

available, software patch number. This information is displayed briefly when you launch the application, and can typically be found in the “About” selection in the “Help” menu.

• It is also helpful if the names of other non-MTS applications that are

running on your computer, such as anti-virus software, screen savers, keyboard enhancers, print spoolers, and so forth are known and available.

Technical Support

SWIFT 20 Sensors

If You Contact MTS by Phone

Your call will be registered by a Call Center agent if you are calling within the United States or Canada. Before connecting you with a technical support specialist, the agent will ask you for your site number, name, company , company address, and the phone number where you can normally be reached.

If you are calling about an issue that has already been assigned a notification number, please provide that number. You will be assigned a unique notification number about any new issue.

Identify system type To assist the Call Center agent with connecting you to the most qualified

technical support specialist available, identify your system as one of the following types:

• Electromechanical materials test system

• Hydromechanical materials test system

• Vehicle test system

• Vehicle component test system

• Aero test system

Be prepared to

troubleshoot

Write down relevant

information

After you call MTS logs and tracks all calls to ensure that you receive assistance and that action

Prepare yourself for troubleshooting while on the phone:

• Call from a telephone when you are close to the system so that you can try

implementing suggestions made over the phone.

• Have the original operating and application software media available.

• If you are not familiar with all aspects of the equipment operation, have an

experienced user nearby to assist you.

Prepare yourself in case we need to call you back:

• Remember to ask for the notification number.

• Record the name of the person who helped you.

• Write down any specific instructions to be followed, such as data recording

or performance monitoring.

is taken regarding your problem or request. If you have questions about the status of your problem or have additional information to report, please contact MTS again and provide your original notification number.

SWIFT 20 Sensors Technical Support

Problem Submittal Form in MTS Manuals

Use the Problem Submittal Form to communicate problems you are experiencing with your MTS software, hardware, manuals, or service which have not been resolved to your satisfaction through the technical support process. This form includes check boxes that allow you to indicate the urgency of your problem and your expectation of an acceptable response time. We guarantee a timely response—your feedback is important to us.

The Problem Submittal Form can be accessed:

• In the back of many MTS manuals (postage paid form to be mailed to MTS)

• www.mts.com > Contact Us > Problem Submittal Form (electronic form to

be e-mailed to MTS)

Technical Support

SWIFT 20 Sensors

Preface

Before You Begin

Safety first! Before you attempt to use your MTS product or system, read and understand the

Safety manual and any other safety information provided with your system. Improper installation, operation, or maintenance of MTS equipment in your test facility can result in hazardous conditions that can cause severe personal injury or death and damage to your equipment and specimen. Again, read and understand the safety information provided with your system before you continue. It is very important that you remain aware of hazards that apply to your system.

Other MTS manuals In addition to this manual, you may receive additional MTS manuals in paper or

electronic form. If you have purchased a test system, it may include an MTS System

Documentation CD. This CD contains an electronic copy of the MTS manuals that pertain to your test system, including hydraulic and mechanical component manuals, assembly drawings and parts lists, and op eration and preventive maintenance manuals. Controller and application software manuals are typically included on the software CD distribution disc(s).

SWIFT 20 Sensors Preface

Conventions

DANGER

WARNING

CAUTION

Conventions

Documentation Conventions

The following paragraphs describe some of the conventions that are used in your MTS manuals.

Hazard conventions As necessary, hazard notices may be embedded in this manual. These notices

contain safety information that is specific to the task to be performed. Hazard notices immediately precede the step or procedure that may lead to an associated hazard. Read all hazard notices carefully and follow the directions that are given. Three different levels of hazard notices may appear in your manuals. Following are examples of all three levels.

Note For general safety information, see the safety information provided with

your system.

Danger notices indicate the presence of a hazard with a high level of risk which, if ignored, will result in death, severe personal injury, or substantial property damage.

Warning notices indicate the presence of a hazard with a medium level of risk which, if ignored, can result in death, severe personal injury, or substantial property damage.

Caution notices indicate the presence of a hazard with a low level of risk which, if ignored, could cause moderate or minor personal injury, equipment damage, or endanger test integrity.

Notes Notes provide additional information about operating your system or highlight

easily overlooked items. For example:

Note Resources that are put back on the hardware lists show up at the end of

the list.

Special terms The first occurrence of special terms is shown in italics.

Illustrations Illustrations appear in this manual to clarify text. It is important for you to be

aware that these illustrations are examples only and do not necessarily represent your actual system configuration, test application, or software.

Electronic manual

conventions

This manual is available as an electronic document in the Portable Document File (PDF) format. It can be viewed on any computer that has Adobe Acrobat Reader installed.

Preface

SWIFT 20 Sensors

Conventions

Hypertext links The electronic document has many hypertext links displayed in a blue font. All

blue words in the body text, along with all contents entries and index page numbers, are hypertext links. When you click a hypertext link, the application jumps to the corresponding topic.

SWIFT 20 Sensors Preface

Conventions

Preface

SWIFT 20 Sensors

Hardware Overview

Data

S20-25

Test Track

Laboratory Simulation

Important This manual includes information on the Low-Profile Transducer

Interface (TI). For SWIFT transducers designed to operate with the newer Mini TI, there is a separate manual that documents the Mini TI, (MTS part number 100214316). For example information in this manual regarding shunt verification, zeroing procedures, or software utilities will pertain to the Low-Profile TI. If you have the Mini TI as a transducer interface, refer to its product manual for related information.

Overview The MTS Spinning Wheel Integrated Force Transducer (SWIFT®) is a light-

weight, easy-to-use transducer that enables you to conduct faster, less expensive data acquisition and road simulation testing.

The transducer is designed for use both on the test track and in the test laboratory. It attaches to the test vehicle or an MTS Series 329 Road Simulator using an adapter and a modified wheel rim.

You can achieve excellent data correlation using the same transducer and vehicle on the test track and on a road simulator. It is available in various sizes and materials to fit various vehicle and loading requirements.

SWIFT 20 Sensors Hardware Overview

Contents Spinning Applications (Test Track) 16

Non-spinning Applications (Simulation Lab) 17 Construction 18

Design Features 22 Coordinate System 23 Specifications 25 Calibration 29 Low-Profile Transducer Interface 31

Low-Profile TI Front Panel 34

Low-Profile TI Rear Panel 41

Low-Profile TI Jumpers 43 Interfacing with RPC 44

Spinning Applications (Test Track)

The SWIFT sensor can be used for road load data acquisition (RLDA) applications:

• Durability

• Noise, Vibration and Harshness (NVH)

• Ride and Handling

• Tire Performance

The transducer is durable enough to withstand harsh road testing and data acquisition environments. The transducer is splash resistant and suitable for use in conditions where the test vehicle will encounter occasional standing or running water, or will be exposed to precipitation. However, it should not be submerged.

In a typical spinning application, the transducer is mounted on a modified rim of a tire on a test vehicle, as shown in the following figure. Data is transmitted from the spinning wheel to the Transducer Interface (TI) electronics via a slip ring mounted on the transducer.The TI, power supply, and data recorder can be located inside the vehicle or in the trunk.

Transducer Signals

Customer Supplied

12 Vdc Power Supply

Spinning Application (Test Track)

Output

Signals

Customer Supplied

Data Recorder

Transducer Interface

(TI)

S20-26

Hardware Overview

SWIFT 20 Sensors

Non-spinning Applications (Simulation Lab)

12 Vdc Power Supply

(with 4 connections)

Customer Supplied

Data Recorder

Transducer Interface

(TI)

Transducer Signals

Output

Signals

Communication

S20-27

Non-spinning Applications (Simulation Lab)

The SWIFT sensor can be fully integrated into the simulation process, since it is an optimal feedback transducer for use with MTS Remote Parameter Control

(RPC

) software. The transducer takes data at points where fixturing inputs are located rather than at traditional instrumentation points along the vehicle’s suspension. Using the SWIFT sensor saves you instrumentation time, and fewer iterations are required to achieve good simulation accuracy.

Measuring spindle loads allows engineers to generate generic road profiles. Generic road profiles are portable across various vehicle models, do not require new test track load measurements for each vehicle, and eliminate additional RLDA tasks.

Four of the six loads measured by the transducer directly correlate to the MTS Model 329 Road Simulator inputs: vertical force, longitudinal force, lateral force, and braking input.

The same transducers used to collect road data at the test track can be mounted directly in the wheel adapters of the MTS Model 329 Road Simulator. For durability testing, an aluminum SWIFT sensor can be used for iterations within the RPC process. The aluminum SWIFT sensor should then be removed for the durability cycles, to preserve its fatigue life. It can be replaced by an adapter plate, available from MTS, to duplicate the mass and center of gravity of the actual SWIFT sensor. If a SWIFT sensor is to be used during full durability tests, we suggest using the titanium model, which has a higher fatigue rating.

In a typical non-spinning application, a SWIFT sensor is mounted on a road simulation test fixture, as shown in the following figure.

Non-spinning Application (Laboratory Simulation)

SWIFT 20 Sensors Hardware Overview

Construction

S20-57

Modified Rim

Hub Adapter

Transducer

Slip Ring

Bracket

Slip Ring

Encoder

Construction

The SWIFT sensor has one-piece construction for outstanding fatigue life, low hysteresis, and high stiffness. Its compact package has a minimal effect on inertia calculations, and a minimal dynamic effect on the test vehicle.

The transducer can be used for developing conventional durability tests on the MTS Model 329 Road Simulator. Normally, the transducer is replaced with an equivalent wheel adapter after the simulation drive signals are developed and prior to the start of the test.

The SWIFT sensor includes several mechanical and electrical components.

Slip Ring Assembly

Transducer The transducer attaches directly to a modified wheel rim. On the test track, it

spins with the wheel. It does not spin on a road simulator. The transducer is available in two materials: aluminum for spinning applications where the priority is on light weight, and titanium for non-spinning or higher force applications, where the priority is on durability.

The transducer’s unibody design means there are no multiple parts welded or screwed together.

The transducer has four beams with strain gages that measure six orthogonal outputs:

Fx—longitudinal force Fy—lateral force Fz—vertical force Mx—overturning moment My—acceleration and brake torque Mz—steering moment

It has onboard conditioning and amplifiers to improve the signal-to-noise ratio.

Hardware Overview

SWIFT 20 Sensors

Construction

Telemetry Model Slip Ring Model

Slip

Ring

Slip Ring

Bracket

Transducer

Interface

Cable Bracket

Anti-rotate Device

(Bend to fit vehicle)

Transducer

Customer-supplied

Attachment Bracket

Wheel Rim

Customer-supplied

Rim Adapter Flange

Attach to

vehicle

suspension

Wheel Rim

Transducer

Anti-rotate

Device

Hub

Adapter

Hub

Adapter

Brake Rotor

Telemetry Bearing

with Hub Electronics

Transducer

Interface

Cable

S20-49

Hub adapter The hub adapter attaches to the inner diameter of the transducer, allowing you to

place it at the original position of the spindle face of the vehicle. The hub adapter enables you to maintain the original position of the tire on the vehicle while the transducer is attached to the vehicle (the tire will not protrude from the vehicle).

Components Set Up for Test Track

Slip ring bracket The slip ring bracket is used to attach the slip ring to the transducer. It has

internal wiring that provides excitation power to the strain gage bridges and brings signals out from the transducer to the slip ring.

Encoder An encoder measures the angular position of the transducer. The SWIFT sensor

uses an optical encoder that counts off “ticks” to measure the angular position as the wheel rotates. In applications using a slip ring, the integral encoder measures 2048 (512 plus quadrature) points per revolution (ppr) with a resolution of 0.18 degrees and an accuracy of 0.18 degrees.

Slip ring The slip ring allows you to output the transducer bridge signals and angular

position to the TI. A transducer data cable attaches from the slip ring to the back panel of the TI. The slip ring is not typically used for non-spinning applications.

Anti-rotate device The anti-rotate device is attached to the stator portion of the slip ring and the

SWIFT 20 Sensors Hardware Overview

vehicle’s suspension (or other non-rotating point). It is able to move up and down with the vehicle. Its primary function is to provide a fixed reference point for the optical encoder. Its secondary function is to prevent the cable from rotating with the wheel and becoming tangled or breaking.

The anti-rotate device is mainly used for road data collection. Although it can also be used for short periods of time on a road simulator. MTS does not recommend this use. Due to the extreme fatigue loading characteristics of durability testing on road simulators, we suggest that you either remove the slip ring assembly before installing the vehicle on a road simulator, or use it only for iteration passes, then promptly remove it.

Construction

S20-55

Slip Ring

Assembly

Suspension/

Unsprung Mass

Tire must not

hit bracket when

loaded or rotating.

Anti-Rotate Bracket

must be stiff

(preferably steel

or stiff aluminum

tubing).

Center line

of Wheel

Anti-Rotate

Assembly

Vehicle Fender

Bracket must not

hit fender at

extreme end of

suspension travel

Slip Ring ModelSlip Ring Model

Cable Conduit

Bracket

Alignment Fixture

Example of Anti-Rotate

Bracket Attached

to Brake Caliper

Example of Anti-Rotate

Bracket Attached

to Strut

Cable Conduit Bracket

Telemetry Model

Accelerometer

(optional)

Shunt A

Load

Shunt B

S20-54

Connector Housing

S20-58

Non-Spinning

Cable Assembly

Non-Spinning

Connector Bracket

Spinning

Slip Ring

Bracket

Non-Spinning

Connector Bracket

The slip ring anti-rotate device should be configured such that no loading occurs to the slip ring throughout all loading and suspension travel. This means that when you attach the anti-rotate device to the vehicle, you must consider all possible motion of the suspension. The anti-rotate device should not bump against the wheel well at any time; any jarring of the anti-rotate arm will damage the slip ring. For steering axles, the anti-rotate bracket must be mounted to part of the unsprung suspension that steers with the tire, such as the brake caliper. For additional anti-rotate device mounting recommendations, refer to the Anti-Rotate Customer/User Assembly drawing at the back of this manual.

Non-spinning

connector housing or

connector bracket

Hardware Overview

The non-spinning connector housing or the non-spinning connector bracket (both shown below) provide a connection between the SWIFT and the TI electronics for non-spinning use. Both assemblies incorporate rugged connectors suitable for durability testing. The non-spinning connector housing can also include an optional connector with built-in, tri-axial accelerometers.

SWIFT 20 Sensors

Construction

Low-profile TI

Mini TI

Transducer Interface

(TI)

The TI comes in two versions: a Low-Profile TI and the newer Mini TI. Information on the Low-Profile TI can be found in this manual. Information on the Mini TI can be found in a separate product manual (MTS part number

100214316). The Low-Profile TI conditions the power supply, and uses previously stored

calibration values to convert the eight bridge outputs and the encoder signal to six non-rotating analog outputs (Fx, Fy, Fz, Mx, My , Mz) plus an angle output (or angular velocity with the Mini TI). The force and moment outputs have a value of 10 V full scale, unless a different full-scale output is requested by a customer. The angle output is a 0–5 V sawtooth output.

Additional

components

SWIFT 20 Sensors Hardware Overview

Additional components that are supplied with your SWIFT sensor include shunt and transducer data cables, TI power cable, a SWIFT Transducer Interface Utilities disk, and the calibration file. MTS can also provide a 12 V DC power converter for use in the test laboratory.

Construction

Design Features

Flexure isolation The SWIFT sensor has a very stiff outer ring and flexured beam isolation which

render it relatively insensitive to stiffness variations in matings with rims and road simulator fixtures.

Flexure isolation minimizes thermal expansion stresses. With flexure isolation, if the inner hub experiences thermal expansion the beams are allowed to expand out, resulting in lower compressive stress on the beams.

Thermal stability The entire sensor is machined from a solid, specially forged billet of high

strength aluminum or titanium. The absence of bolted joints permits an efficient transfer of heat across the sensor structure, minimizing temperature differentials in the gaged area.

As mentioned earlier, flexure isolation allows thermal expansion with minimal stresses.

The transducer is designed to accommodate the high temperature environments that occur during severe driving and braking events. Individual temperature compensation of each strain gage bridge minimize temperature induced variations in accuracy. Since minimal electronics reside on the SWIFT sensor, it can easily tolerate high temperatures. The temperature rating for the SWIFT sensor is 125° C (257° F) at the spindle hub.

Temperature compensation is done on each bridge for better performance in transient or non-uniform temperature occurrences.

Low hysteresis The SWIFT sensor has very low hysteresis, since the sensing structure is

constructed with no bolted joints. Micro slippage in bolted joints contributes most of the hysteresis in highly stressed structures. Hysteresis errors due to micro-slip at joints can contribute to unresolvable compounding errors in coordinate transformation of the rotating sensor.

Low noise On-board amplification of the transducer bridges minimizes noise contribution

prior to data transmission via low noise slip ring.

Low cross talk The advanced design of the SWIFT sensor means that it has very low cross talk.

The alignment of the sensing element is precision machined. This alignment is critical to achieving minimum cross talk error between axes and minimum errors in coordinate transformation (from a rotating to a nonrotating coordinate system). Any small amount of cross talk present is compensated by the TI.

Velocity information Angular position output is available from the TI when it is used in the spinning

mode with the encoder. For the Low-Profile TI, this angular out put can be used to calculate wheel velocity. In non-spinning applications, accelerometers can be integrated into the transducer connector housing.

The Mini TI has a user selectable angle or angular velocity output.

Hardware Overview

Note MTS does not supply any conditioning electronics for accelerometers.

Ask your MTS consultant for more information about this option.

SWIFT 20 Sensors

Coordinate System

Transducer

Interface

Output signals

10 Volts

Angular Position

Bridge

Outputs

S20-06

+Mz

+Fz

+Fy

+My

+Mx

+Fx

Forces acting on outer ring

S20-07

In the transducer, independent strain gage bridges measure forces and moments about three orthogonal axes. The signals are amplified to reduce the signal-tonoise ratio. An encoder signal indicates angular position, which is used to convert raw force and moment data from the rotating transducer to a vehiclebased coordinate system. The force and moment and encoder information is sent to the transducer interface (TI).

Coordinate System

The TI performs cross talk compensation and converts the rotating force and moment data to a vehicle coordinate system. The result is six forces and moments that are measured at the spindle: Fx, Fy, Fz, Mx, My, and Mz. A seventh (angle) output is available for tire uniformity information, angular position, or to determine wheel speed (depending on the data acquisition configuration).

The coordinate system shown below was originally loaded into the TI settings by MTS. It uses the right-hand rule.

The SWIFT coordinate system is transducer-based, with the origin located at the

reference drawings at the end of this manual. Positive loads are defined as applied to the outer ring of the transducer.

SWIFT 20 Sensors Hardware Overview

center of the transducer. The lateral offset of the transducer is illustrat ed in the

Coordinate System

The direction of positive forces follows the right hand rule:

• Vertical force (Fz) is positive up

• Lateral force (Fy) is positive out of the vehicle

• Longitudinal force (Fx) is positive fore or aft of the vehicle depending on

which side of the vehicle the SWIFT is mounted

You can change to the MTS Model 329 Road Simulator convention (lateral load into the vehicle is always positive) or to any coordinate system by changing the polarities in the calibration file. For instructions on how to change the coordinate system polarities, see the chapter, “Setting up the Transducer Interface” in this manual or refer to “Transducer Interface Setup” in the Mini TI manual.

The Mini TI has the capability to offset the coordinate system. For example you can offset the coordinate system such that the coordinate system is at the center of the rim instead of the default coordinate system location at the center of the transducer. The Mini TI manual has additional information.

Hardware Overview

SWIFT 20 Sensors

Specifications

SWIFT 20 Transducer Performance

Parameter Specification

Use

SWIFT 20 A (aluminum) for

SWIFT 20 T (titanium) for Maximum usable rpm Maximum speed fits rim size (usable range)

Maximum hub bolt circle diameter accommodates M12 or 1/2 inch studs

Input voltage required Input power required per transducer Output voltage ± full scale calibrated load

Aluminum Titanium

SAE J328 rated load capacity Standard Maximum Calibrated Load Rating‡

Longitudinal force (Fx)

Lateral force range (Fy)

Vertical force range (Fz)

Overturning moment (Mx)

Driving/braking moment (My)

Steering moment (Mz) Resolution (analog system) Noise level (peak-to-peak 0-500Hz) Performance accuracy

Nonlinearity

Hysteresis

Modulation§

Cross talk Maximum operating temperature

Low level amplifiers

Transducer interface

* A special flange configuration is required for a 12 inch wheel. Larger diameter rims can be used, providing that overall

clearance from brake calipers and suspension components is maintained. † Load impedance >1 k ‡ The actual calibrated range may be different based on individual customer requirements. Consult the calibration range

sheet that accompanies each transducer for the correct calibration range.

§ Typical value on most steel rims. Aluminum rims typically have slightly higher modulation, but at a lower added weight. # Each SWIFT sensor is calibrated on an MTS calibration machine. MTS provides complete documentation of calibration

values for each SWIFT unit

Ω; 0.01 µF (maximum) load capacitance.

4.3 kN (965 lbf) 7.0 kN (1,580 lbf)

±21 kN (±4,720 lbf) ±30 kN (±6,745 lbf) ±16 kN (±3,595 lbf) ±25 kN (±5,620 lbf)

±21 kN (±4,720 lbf) ±30 kN (±6,745 lbf) ±4 kN•m (±35,405 lbf•in) ±6 kN•m (±53,105 lbf•in) ±5 kN•m (±44,255 lbf•in) ±8.5 kN•m (±75,230 lbf•in) ±4 kN•m (±35,405 lbf•in) ±6 kN•m (±53,105 lbf•in)

15 N (3.4 lbf) 25 N (5.6 lbf)

low weight, high sensitivity

high fatigue life, durability

2,200

240 kph (150 mph)

12–15 inch

4.5 inch (114.3 mm)

10–17 VDC

30 W maximum (22 W typical)

†

±10 V

Infinite

1.0% full scale

0.5% full scale ≤3.0% reading

1.5% full scale

70°C (158°F) 50°C (122°F)

SWIFT 20 Sensors Hardware Overview

Specifications

Transducer Center-of-Gravity

Transd ucer Center-of-Gravity and Inertia Specifications

Material

Aluminum Titanium

0.0 mm 0.000 in 0.0 mm 0.000 in

19.2 mm 0.755 in 19.2 mm 0.755 in

0.0 mm 0.000 in 0.0 mm 0.000 in

180 kg·cm262 lbm·in2290 kg·cm299 lbm·in

353 kg·cm2121 lbm·in2569 kg·cm2195 lbm·in

180 kg·cm262 lbm·in2290 kg·cm299 lbm·in

Low-Profile Transducer Interface (part 1 of 2)

Parameter Specification

Physical

Height Width Depth Weight Rack Mounting Kit

31.75 mm (1.25 in)

431.8 mm (17 in)

215.9 mm (8.5 in.)

1.68 kg (3 lb 11.1 oz) Optional

Environmental

Ambient temperature Relative humidity

Hardware Overview

0° C (32° F) to 50° C (122° F) 0 to 85%, non-condensing

SWIFT 20 Sensors

Low-Profile Transducer Interface (part 2 of 2)

Parameter Specification

Power Requirements

Input voltage Supply current Fuse

Angular velocity

Encoder limit Processing limit Encoder resolution

10–17 V DC 2 A typical, 3 A maximum at 12 V DC 3 A fast-blow

2,200 rpm maximum 10,000 rpm maximum 2048 counts per revolution

(512 pulses with quadrature)

Specifications

Time delay (encoder tick to main outpu t stable) Transducer cable length Shunt cable length Analog outputs

Voltage

12 µs (typical) 100 ft maximum 100 ft maximum

±10 V range† (force and moment outputs) 0–5 V sawtooth (angle output)

Capacitive load Current Noise at output, with typical gains

0.01 µF maximum 6 mA maximum 7 mVpp, DC - 500 Hz (typical)

15 mVpp, DC - 500 Hz (maximum)

Bandwidth (bridge input to main output)

–3 dB at 30.1 kHz (typical) 90 degree at 16.6 kHz (typical)

* Add 25.4 mm (1.0 in) for ground lugs. † Standard from MTS. Other full scale voltages can be evaluated and may be provided at special

request.

Low-Profile Transducer Interface Communications (part 1 of 2)

Parameter Specification

Communications Channel # 1 (Remote Host Connections)

Baud rates Parity Stop bits Data bits Isolated RS-232/RS-485 interface power

supply Electrical interface

19,200 Kbits/s None 1 8 +5 V DC @ 200 mA maximum

Isolated RS-232 or RS-485 remote host connection Isolated RS-485 TI to TI connection

Maximum number of devices that can be part of a RS-485 multidrop chain

32 with RS-232 remote host 31 with RS-485 remote host

Maximum cable length

SWIFT 20 Sensors Hardware Overview

Specifications

Low-Profile Transducer Interface Communications (part 2 of 2)

Parameter Specification

For RS-232 host:

50 ft from host to the first (nearest) TI, and 300 ft from the first TI to the last SWIFT TI in the RS-

485 multidrop chain

For RS-485 host:

300 ft from host to the last (furthest) TI in the RS-485 multidrop chain

* Includes all compatible devices, such as an MTS 407 controller. A maximum of only nine transducer

interfaces can be connected, because the addresses are limited to 1–9.

Hardware Overview

SWIFT 20 Sensors

Calibration

Important The following sections include information related to the Low-

Profile Transducer Interface (TI). For SWIFT transducers designed to operate with the newer Mini TI, there is a separate manual that documents the Mini TI software utilities (MTS part number

100214316).

Each transducer is calibrated by MTS before shipment. The transducer and LowProfile TI may be returned to MTS for repair and recalibration as required.

Calibration is performed at MTS on a special fixture that is capable of applying multiple loads to the transducer. During calibration, raw signals are measured. The calibration gains and cross talk compensation values are computed from this raw data. These gains are recorded in a calibration file.

A unique calibration file is supplied for each transducer. The serial number of the Low-Profile TI associated with the transducer is listed at the top of the calibration file. A label with the serial number of the Low-Profile TI box (and the SWIFT sensor with which it was originally calibrated) is located at the back of each Low-Profile TI box.

The calibration file is loaded into the Low-Profile TI non-volatile RAM by MTS before the transducer is shipped. A copy of the file is also provided on a diskette.

MTS verifies the calibration by applying loads to the transducer, measuring the main outputs and checking for accuracy. Final calibration reports are provided with each transducer.

Shunt calibration At the end of the calibration process, a shunt calibration is performed. During a

shunt calibration, a resistance is introduced into the bridge circuit. The difference between the shunted and unshunted voltage is the delta shunt reference value for each bridge. That value is saved in the calibration file, which is downloaded from a PC or laptop computer and stored in non-volatile memory in the Low-Profile TI.

At any time afterward, pressing the Shunt button on the front of the Low-Profile TI causes each of the strain gage bridges to be shunted in sequence, and the measured shunt voltage (delta shunt measured value) is compared to the reference value.

An acceptable tolerance range is also loaded into the Low-Profile TI memory during system calibration. One tolerance value is used for all bridges. This value is loaded as a percentage of allowable deviation from the delta shunt values. For example, if the FX1 bridge has a shunt delta reference value of –3.93, and the tolerance is set at 2 (percent), the acceptable range for the measured value would be –3.85 to –4.01.

SWIFT 20 Sensors Hardware Overview

Calibration

When you press the Shunt button, the associated Shunt LED lights. As the LowProfile TI automatically switches throug h the series of bridges, it verifies that the outputs are within the accepted tolerance range. If all bridge shunt values fall within the tolerance range, the Shunt LED on the front panel will go off (after several seconds). If any bridge fails to fall within the shunt tolerance range, the LED will blink, indicating that the shunt calibration has failed. See the chapter,

“Troubleshooting,” on page 127, for more information on dealing with shunt

calibration failures.

ShuntTolerance=2 FX1ShuntDeltaRef=-3.91836 FX2ShuntDeltaRef=-3.91896 FY1ShuntDeltaRef=-3.92366 FY2ShuntDeltaRef=-3.91639 FY3ShuntDeltaRef=-3.91824 FY4ShuntDeltaRef=-3.92494 FZ1ShuntDeltaRef=-3.92282 FZ2ShuntDeltaRef=-3.92673 FX1ShuntDeltaMeas=-3.91854 FX2ShuntDeltaMeas=-3.9192 FY1ShuntDeltaMeas=-3.92412 FY2ShuntDeltaMeas=-3.91572 FY3ShuntDeltaMeas=-3.91815 FY4ShuntDeltaMeas=-3.92464 FZ1ShuntDeltaMeas=-3.9227 FZ2ShuntDeltaMeas=-3.92646

Example of Calibration File Shunt Data

The above example shows shunt data from the calibration file. This data may be transferred, using the TIXFER program, from the transducer interface RAM to a computer or from a computer to the transducer interface RAM. Note that items marked ShuntDeltaMeas are uploaded from RAM, but not downloaded from the computer. (For more information on TIXFER, see the chapter, “Software Utilities.”

Shunt verification You can check the electrical integrity of a transducer at any time by pressing the

Shunt switch. Subsequent shunt commands compare the current feedback values against those stored in the Low-Profile TI. You may set the tolerance values for each Low-Profile TI by editing the calibration file (see the chapter, “Setting up the Transducer Interface”, for instructions).

If the current feedback values from a shunt calibration are outside the tolerance, the Shunt LED blinks to indicate a failure.

Hardware Overview

SWIFT 20 Sensors

Low-Profile Transducer Interface

Transducer

Interface

Output signals

(± 10 Volts)

Angular Position

Bridge

Outputs

Transducer bridge output

signals and encoder

angular position signal are

sent through slip ring

Transducer Interface

converts signals to nonspinning vehicle coordinates, applies calibration gains and

cross talk compensation

Force, moment, and

angle analog signals

are output from

Transducer Interface

Angle signal

(05 Volts)

S20-08

The Low-Profile TI performs cross talk compensation, transforms the loads from a rotating to a non-rotating coordinate system, and produces an analog output signal suitable for any data recorder.

Low-Profile Transducer Interface

SWIFT 20 Sensors Hardware Overview

Cross talk

compensation

Cross talk occurs when a force is applied to one axis, but a non-real force is measured on another axis. The SWIFT sensor design has very low inherent cross talk. The Low-Profile TI compensates for any cross talk by subtracting the nonreal forces when the amount of cross talk is known.

The amount of known cross talk is determined during the calibration process. Cross talk values will vary slightly for different rims. For example, a steel rim will have slightly different cross talk errors than a less rigid aluminum rim.

Signal conditioning The Low-Profile TI is specifically designed to be used for both spinning and non-

spinning applications. The Low-Profile TI performs signal conditioning and communications functions. The output from the Low-Profile TI is a high-level signal suitable for input into a multichannel data recorder or an MTS Automated Site Controller (ASC).

Low-Profile Transducer Interface

Fx1 Fx2 Fy1 Fy2 Fy3

Fy4 Fz1 Fz2

Fx Fy Fz Mx My

Geometric

Matrix

Zero and

Scaling

Cross

Coupling

Matrix

Rotational

Transformation

Inputs Output

Transducer Interface Functions

S20-09

The Low-Profile TI transforms eight inputs (amplified bridge signals) into three forces and three moments by the following process:

• Applying a zero offset and scaling the signals

• Using a geometric matrix to transform the signals into three forces and three

moments in the transducer reference frame

• Using a cross-coupling matrix calculation to scale and sum the individual

signals into each output

• In spinning applications, using a rotational transformation to put the forces

and moments into a stationary reference frame

The Low-Profile TI conditions the transducer signals, producing seven analog output signals proportional to the following values:

• Longitudinal force (Fx)

• Lateral force (Fy)

• Vertical force (Fz)

• Overturning moment (Mx)

• Driving/Braking moment (My)

• Steering moment (Mz)

• Angle output (θ)

Analog signals The force and moment signals are output from the Low-Profile TI in the form of

full scale analog signals. These signals can be used by any data

±10 V acquisition system.

The angle output is an analog voltage that is proportional to angular position. At 0° the output is 0 V. At 360°, the output is 5 V.

Hardware Overview

1. Standard from MTS. Other full-scale output voltages can be evaluated and may be provided at special request.

SWIFT 20 Sensors

Low-Profile Transducer Interface

0 360°

0° 360°

Angle

Output

1 rev = 360°

S20-10

The angle output for a tire rotating at constant velocity can be represented by the following illustration:

Although you may not routinely use it, the angle output information is available for tasks such as tire uniformity testing and troubleshooting. You may also calculate angular velocity by measuring the frequency of the angle output signal.

Communications The Low-Profile TI provides a serial port for remote communication. The port

allows connection to an RS-232 or RS-485 host for multidrop communication. This interface is compatible with the MTS 407 Controller protocol, and 407 Controllers may also be in the same multidrop communication chain. A multidrop configuration can include up to 32 total devices in any combination, with a maximum of nine Low-Profile TIs (limited to addresses 1 through 9).

The serial interface provides the following capabilities:

• allows the user to save and restore Low-Profile TI setup parameters.

• is compatible with LabVIEW®.

• is compatible with serial port-equipped computers (UNIX machines,

Macintosh, and IBM PC).

• is able to link multiple Low-Profile TIs (and 407 Controllers) to one host

computer.

SWIFT 20 Sensors Hardware Overview

Low-Profile Transducer Interface

S20-11

Fuse

Power Switch

and Indicator

Shunt Switch and Indicator

Angle Zero

Switch and Indicator

Bridge Zero

Switch and Indicator

Fail

Indicator

Transmit Indicator

Address Selector

Low-Profile TI Front Panel

Transducer Interface Front Panel

Fuse (F1) A 3A fuse protects the electronics.

Power switch and

Indicator

The power switch turns power on and off. A green indicator will light to indicate that the Low-Profile TI power is turned on.

Shunt switch Pressing this switch performs a shunt calibration (shunt cal) of the transducer.

Y ou do not need to hold the switch in continuously, only until the Shunt indicator lights up (indicating that the Low-Profile TI has started the shunt cal).

Before you perform a shunt cal, check that the appropriate shunt reference value and error tolerance have been downloaded (these values are normally loaded during system calibration, and are referred to as the shunt delta cal values).

A shunt calibration will determine the current delta values by measuring the bridges unshunted and shunted, and then compare these values to the previously loaded calibration values. If the measured values are outside of an acceptable tolerance, the Shunt indicator will flash, indicating an error.

Shunt Indicator This indicator indicates the current state of the shunts. If there are any active

shunts, or if you are currently performing a shunt calib ration, this indicator will be lit.

If the shunt cal check fails, this indicator flashes (at approximately a 1 Hz rate).

Note The state of the shunt cal check is cleared at power-up, so the shunt cal

should be performed when the system installation is in question.

Hardware Overview

SWIFT 20 Sensors

Low-Profile Transducer Interface

Angle Zero and Bridge

Zero switches

These switches are used to zero the transducer inputs. Which switch you press depends on the ZeroAlgorithm that you specified in the calibration file (see following illustration). Two different methods are used to zero the system: spinning and non-spinning. For more detailed information on selecting a zero method, see the chapter, “Setting up the Transducer Interface.”

When you select a zero method, it will activate the appropriate switch on the Low-Profile TI front panel. Each switch performs a specific zero function:

Angle Zero– Angle offsets are required for spinning applications only. This switch is active when the ZeroAlgorithm=1, or 3. The Low-Profile TI reads the current angle and compensates for any offset from the Z axis facing up. You will not use this switch for non-spinning applications.

SWIFT 20 Sensors Hardware Overview

Bridge Zero–Bridge offsets are required for both spinning and non-spinning applications. This switch is active when the ZeroAlgorithm=0, 1, or 3. The Low-Profile TI reads the transducer bridge values and compensates for any offsets so that the bridge output is 0 at 0.0V.

Low-Profile Transducer Interface

Angle Zero and Bridge Zero Switch Functions

Zero

When to Use Angle Zero Bridge Zero

Algorithm

(Preferred method for non-spinning applications)

Use this algorithm for nonspinning (fixed) applications.

Use this algorithm for spinning applications.

You will need to mechanically level the SWIFT sensor.

Use this algorithm for spinning applications.

You do not need to mechanically level the SWIFT sensor.

(Preferred method for spinning applications)

Use this algorithm for spinning applications.

You will need to mechanically level the SWIFT sensor.

When a system zero is initiated, the associated LED is lit. After successful completion of the system zero, the LED turns off. If there is a failure during the system zero, the LED will flash at approximately a 1 Hz rate.

The Angle Zero switch is non-functional.

Press the Bridge Zero switch to measure and tare out the static transducer bridge offsets.

Press the Angle Zero switch to read the current angle and use the value to set the angle sum to 0.0°.

Press the Bridge Zero switch and rotate the transducer to measure the static transducer bridge offsets.

Both the Angle Zero and Bridge Zero switches are functional. This algorithm will perform both angle zero and bridge zero processes based on two rotatio n s of the SWIFT sensor regardless of which button you press.

Both the Angle Zero and Bridge Zero switches are functional. This algorithm will perform both angle zero and bridge zero processes from a two-point zeroing procedure.

Hardware Overview

SWIFT 20 Sensors

Low-Profile Transducer Interface

Zero LEDs These indicators indicate the current state of the zero process. The

ZeroAlgorithm value (0, 1, 3, or 4) you selected in the calibration file will determine the state of the indicators when you press either the Bridge Zero or the Angle Zero button.

• The indicators are off under normal operating conditions

• In non-spinning applications using ZeroAlgorithm=0 (required), press the

Bridge Zero button. The Bridge Zero indicator will light for 3–4 seconds while the Low-Profile TI is completing the bridge zero process.

• In spinning applications using ZeroAlgorithm=1 (alternate), pressing the

Bridge Zero button will light the Bridge Zero indicator continuously (no flashing) until the wheel is spun for one revolution (index-to-index). This may take up to two full revolutions, depending on where the encoder index pulse starts. After one revolution of data is collected, the Bridge Zero indicator will flash rapidly for 30 seconds while the data is analyzed and the bridge zeroes are calculated.

• When you press the Angle Zero switch, the Angle Zero indicator will light

for a few seconds while the Low-Profile TI reads the current angle and sets the angle offset value.

• In spinning applications using ZeroAlgorithm=3 (alternate), both the

Bridge Zero and Angle Zero indicators will light continuously until the wheel is spun for one revolution (index-to-index). After one revolution of data is collected, both indicators will blink rapidly for approximately two minutes while the Low-Profile TI analyzes the data and calculates both the angle offset and bridge zero values.

• In spinning applications using ZeroAlgorithm=4 (preferred), the Bridge

Zero and Angle Zero indicators will initially be off. After the wheel is turned at least 1.25 turns, in order for the Low-Profile TI to locate the index, the level can be installed and leveled. With the wheel orientated such that Fz on the axis icon on the transducer is facing up, pressing the Bridge Zero button will light the Bridge Zero indicator continuously for a few seconds, then the indicator will start blinking rapidly. The Angle Zero indicator will start blinking slowly.

• With the wheel orientated such that Fx on the axis icon on the transducer is

facing up, pressing the Angle Zero button, will light the Angle Zero indicator continuously for a few seconds. Then both the Bridge Zero and Angle Zero indicators will turn off.

the algorithm was unable to calculate zero, the Fail indicator will light

• If

momentarily and both the Bridge Zero and Angle Zero indicators will blink continuously at approximately a 1 Hz rate.

• If no successful zero has been performed for the currently selected zero

algorithm, the Bridge Zero and Angle Zero indicators will flash (at approximately a 1 Hz rate), until a zero has been initiated. Use the TISTATUS utility for a detailed explanation of th e problem.

After successful completion of a zero algorithm, the Bridge Zero and Angle Zero indicators turn off. Should the system zero fail, the indicators will return to a flashing state.

SWIFT 20 Sensors Hardware Overview

Low-Profile Transducer Interface

Address selector Each Low-Profile TI in a communications chain has a unique address. This

address is used in every read or write command from the host computer. The host can transmit to only one Low-Profile TI at a time, using its assigned address. The Low-Profile TI will reply to the host when it has received a command.

The address selector switch allows you to set the communication address for the Low-Profile TI. When multiple TIs are connected, each must have a unique address. The address must be 1 to 9. Address 0 is used only for broadcast messages from the host. In the case of broadcast messages, the Low-Profile TI does not respond to the host.

T o change an address, insert a small screwdriver in the slot and turn the dial until the arrow points to the desired address number.

Note Make sure every Low-Profile TI on a communications chain has a unique

address. If you set two TIs on one communications chain to the same address, you may experience unpredictable communications errors.

If two Low-Profile TIs on one communications chain have the same address, communications to either Low-Profile TI will be unreliable. (The errors are unpredictable, but will probably be parity or framing errors.) Assigning the same address to two TIs does not damage the hardware.

Transmit Indicator The green Transmit indicator lights to indicate that the Low-Profile TI is

transmitting information via the COMM IN connector.

FAIL Indicator The red Fail indicator lights to indicate that a fail condition exists on the board.

Depending on the failure detected, the Fail indicator will either be on constantly or will flash a repetitive pattern that can be used to identify the failure detected.

Certain failures are considered critical, and will result in the Low-Profile TI becoming completely unusable. These failure conditions must be resolved before the Low-Profile TI can be used. If a critical failure occurs, the Fail indicator will only blink the cause of the first critical failure. This failure code will be repeated approximately every 1 second.

Non-critical failures indicate impaired system functionality, which, in most cases, can be corrected operationally from the communication interface. Noncritical failure codes are checked cyclically, so that multiple failure conditi ons can be communicated. Failure codes are indicated approximately every 1.5 seconds.

The following table lists fail conditions and the manner in which the Fail indicator indicates the failure.

Error Codes for the Fail Indicator (part 1 of 3)

Fail Indicator State

[Number of blinks:]

Error

Off Continuous On Fast blinking Fast varying blink 1

Hardware Overview

No error detected

Critical: Boot failure; bad code in boot block Critical: Unanticipated exception prior to relocation of loader code Critical: Unanticipated exception after relocation of loader code Critical: SRAM failure

SWIFT 20 Sensors

Fail Indicator State

[Number of blinks:]

Low-Profile Transducer Interface

Error Codes for the Fail Indicator (part 2 of 3)

Error

Critical: Local register failure

3 5

10 11

Critical: Boot block CRC failure NVRAM error. An error was detected during the NVRAM self-test. This

self-test is performed at every power-cycle, and verifies that the NVRAM checksum is valid, and also that the data stored is compatible with the current firmware version. A failure of this test will require an NVRAM Init command to be issued. Issuing this command will result in all stored settings being cleared.

Self-T est fail. A failure was detected during the commanded self-test (note that this is different than the power-up self-test). Further information can be obtained by reading the self-test error status.

Operational error. These errors are usually caused by issuing communication commands with invalid Command IDs, out-of-range data, invalid slot number, and so on. This error condition is cleared after the Fail indicator has indicated it.

Serial EEPROM Error. A checksum or version error was detected on the serial EEPROM data. This data stores normalization values.

AD Failure. An error (gain out of range or off set ou t of r ange) o ccurred o n at least one A/D, when the A/D gains and offsets were set. The ability to perform a zero, self-test or shunt tests may be impaired in this state.

Issuing a Cal A/D command may clear this state.

Critical: Memory allocation failur e Critical: An unexpected interrupt occurred.

Communication Interface Init Error. An error occurred while attempting to initialize the communication interface. The communication interface may be unusable in this state.

Low-Profile TI Firmware Init Error . An error occurred while attempting to initialize the Low-Profile TI firmware. The communication interface may be unusable in this state.

Box ID Error. An error occurred while attempting to initialize the LowProfile TI Box ID. The communication interface may be unusable in this state.

DAC Init Error. An error occurred while attempting to initialize the LowProfile TI DACs. The functionality of the Low-Profile TI may be impaired in this state.

Switch Init Error. An error occurred while attempting to initialize the LowProfile TI switches. The functionality of the Low-Profile TI may be impaired in this state.

Encoder Init Error. An error occurred while attempting to initialize the Low-Profile TI encoder interface. The functionality of the Low-Profile TI may be impaired in this state.

SWIFT 20 Sensors Hardware Overview

Low-Profile Transducer Interface

Error Codes for the Fail Indicator (part 3 of 3)

Fail Indicator State

[Number of blinks:]

Error

AD Init Error. An error occurred while attempting to initialize the LowProfile TI A/Ds. The ability to perform a self-test, and/or shunt tests may be impaired in this state.

Shunt interface Init error. An error while attempting to initialize the shunt interface. The shunt interface may be unusable in this state.

Hardware Overview

SWIFT 20 Sensors

Low-Profile TI Rear Panel

J2A Shunt A

and J2B Shunt B

J4 Output

Comm In and

Comm Out

J3 Power

Ground

Terminals

S20-31

Transducer

Connector

Slip Ring

Daughter Board

Telemetry

Daughter Board

Data

Connector

Encoder

Output Connector

Indicators

Error/Low Power/Ready

Low-Profile Transducer Interface Rear Panel

Low-Profile Transducer Interface

J4 Output connector The J4 Output connector provides the conditioned sensor outputs that can be

connected to a data acquisition or test control system.

J2A Shunt A J2B Shunt B

The J2 connectors are used for the shunt cables. The shunt cables are connected to the two 6-pin shunt cal connectors on the front of the transducer.

connectors

Comm In Comm In is an 8-pin modular phone jack connector (RJ-45) that provides a

connection to an RS-232/RS-485 remote host, or to another Low-Profile TI in an RS-485 multidrop communications chain. The cable connected to Comm In selects an RS-232 or RS-485 interface. The RS-232/RS-485 interfaces on Comm In are electrically isolated from the Low-Profile TI power. This connection is only needed when you are downloading new settings to the Low-Profile TI module.

Under normal operating conditions, no host connection is required. The Comm In and Comm Out connectors allow you to daisy-chain multiple boxes without Y cables or multiple connections to the host computer.

Comm Out Comm Out is an 8-pin modular phone jack connector (RJ-45) that provides a

connection to another Low-Profile TI chassis in an RS-485 multidrop communication chain.

J3 Power connector Connect a power cable from an external 12 V DC source.

Ground Terminals The ground terminals enable you to ground the Low-Profile TI, and chain several

Low-Profile TI boxes together.

Slip ring daughter

board

A slip ring daughter board must be installed in the Low-Profile TI when a SWIFT transducer with a slip ring will be mounted on the vehicle

Transducer connector Connect the data cable from the transducer slip ring to the Transducer Connector.

SWIFT 20 Sensors Hardware Overview

Low-Profile Transducer Interface

Power Switch

Fuse (F3)

J1 Power

Ground

Terminal

Fuses (F1, F2)

Power

Indicator

RF Output Connector

Gain

(trim pot)

S20-32

Front

Rear

Induction Power Source

Fuses (F1, F2) Provides circuit protection for up to two systems.

Induction Power Source

Power indicator Indicates (green) when power is available to the induction power source.

RF output connector Provides power for up to two system.

Gain (trim pot) Allows you to adjust the power gain if the LPwr indicator on the daughter board

if the Low-Profile TI is blinking, indicating the power available to the system is marginal.

Power switch Controls power to the induction power source.

Fuse (F3) Provides circuit protection for the induction power source.

J1 Power Connects the induction power source to an external 12 V DC source.

Ground terminal The ground terminal enables you to ground the induction power source.

Hardware Overview

SWIFT 20 Sensors

Low-Profile TI Jumpers

S20-13

The transducer interface uses circuit board jumpers to establish certain parameters and make use of various electronic functions. These jumpers are set at the factory, and should not be reset. Th e followi ng table is for reference only.

Jumper Setting Function

Low-Profile Transducer Interface

1–2 2–3

X4 removed X5 installed

removed

X6 installed

removed

Excitation setup for shunts FX1, FY1, FY4, and FZ2. Sets up – (minus) excitation for shunts FX1, FY1, FY4, and FZ2. Sets up + (plus) excitation for shunts FX1, FY1, FY4, and FZ2.

Excitation setup for shunts FX2, FY2, FY43 and FZ1. Sets up – (minus) excitation for shunts FX2, FY2, FY43 and FZ1. Sets up + (plus) excitation for shunts FX2, FY2, FY43 and FZ1. Not used for Low-Profile TI applications (Standard setting). Enables the ability to download new code to the block of FLASH RAM

where the boot code is stored. Disables the ability to download new code to the block of FLASH RAM

where the boot code is stored (Standard setting). Boots to the FLASH memory down-loader. Boots to the Transducer Interface software (Standard setting).

Low-Profile TI PWB Jumper Locations

SWIFT 20 Sensors Hardware Overview

Interfacing with RPC

The SWIFT sensor is directly compatible with the MTS Remote Parameter Control (RPC) simulation software. The SWIFT system produces outputs that directly correspond to the uncoupled spindle forces that the MTS Model 329 Road Simulator applies to the vehicle. Traditional instrumentation techniques provide coupled suspension loads data. Using the SWIFT sensor, the RPC simulation software needs to apply less correction to obtain the road simulator drive signals. Fewer iterations are required to recreate the measured loads.

You must ensure that the full scale value for your data recorder and the MTS Series 498 electronics match. MTS electronics are typically set at ±10 V full scale, while some data recorders are ±5 V full scale.

The SWIFT sensor is calibrated for ±10 V full scale. To recompute the LowProfile TI gains for ±5 V full scale, a verification pass must be run or the calibration will not be traceable. Upon special request, MTS can evaluate and may provide calibration for ±5 V or other full scale voltages.

Hardware Overview

SWIFT 20 Sensors

Software Utilities

Important This section includes information related to the Low-Profile

Contents Introduction 46

TISTATUS - Low-Profile Transducer Interface Status 47 TIXFER - Low-Profile Transducer Interface Transfer 48 TISHUNT - Low-Profile Transducer Interface Shunt 51 TISETZERO – Low-Profile Transducer Interface Set Zero Method 56 Error Messages 57 Shunt Error Status 58

Transducer Interface (TI). Fo r SWIFT transducers designed to operate with the newer Mini TI, there is a separate manual that documents the Mini TI software utilities (MTS part number

100214316).

SWIFT 20 Sensors Software Utilities

Introduction

The SWIFT utility programs in this distribution are for Win32 Operating Systems (Windows 95, 98, NT, 2000, XP). They are designed to be run from the Command Prompt or MSDOS Shell. However, it is possible to create a shortcut to run the programs. If launched from a shortcut the application window may close immediately when the application terminates making it impossible to see any error messages. The Command Prompt application is usually found in Start–>Programs–>Accessories but the actual location depends on the version of your operating system.

To run a SWIFT utility program

• Copy it to your computer. For example, create the folder

the executables (*.exe) to that folder.

• Launch Command Prompt

• Change the working directory to where you copied the executables: cd bin.

This step can be eliminated if you set up the PATH environment variable to include the directory where you copied the SWIFT utility executables.

• Type the name of a SWIFT utility program providing the necessary

command line arguments: provided the program will display a simple help message. This is helpful if you forget the order of the command line arguments.

In the Windows environment the SWIFT utilities programs define port 1 as COM1: and port 2 as COM2:. Which communications port you specify depends on which connector on the computer the serial communications cable is plugged into. T o confuse things, some computers label the communications connectors as “A” and “B”.

tixfer 1. If no command line arguments are

C:\bin and drag

Software Utilities

1. You may want to change the layout properties for the Command Prompt

window to display a larger area or to increase the screen buffer size. Within Command Prompt, select Properties and the Layout tab to modify the screen buffer size or window size.

2. In Windows 2000 the environment variables can be changed at

Start–>Control Panels–>Systems. Click on the Advanced tab, and the Environment Variables… button. The path is a system variable. Adding

;c:\bin, or whatever directory name you used, to the end of the string will

cause Command Prompt to search that directory for applications.

SWIFT 20 Sensors

TISTATUS - Low-Profile Transducer Interface Status

This program is used to get status information from the SWIFT Low-Profile Transducer Interface (TI). When the Low-Profile TI has encountered a problem and is blinking an error code, this program can be used to easily interpret the error. For certain errors this program may provide additional information. The program also provides information such as the internal power supply voltages.

Note The power supply voltages displayed may be unreliable if the power

supplies are too low, as the circuit used to measure the power supply also depends on the available power.

Syntax The tistatus command requires two arguments:

tistatus port box

port is the communications serial port number

1 = COM1: 2 = COM2:

box is the Low-Profile TI communications address

1 = lowest possible address 9 = highest possible address

Example

C:\bin>tistatus 1 1

tistatus $Revision: 1.6 $ ($Date: 2002/04/10 21:05:49 $)

Reads status from the SWIFT Transducer Interface Requires that the remote comm port be configured for 19200 baud, 8 data bits, no parity, 1 stop bit.

Tue Dec 28 10:15:14 2004 Firmware Version: 2.6.1 Ground = 0 +5V Supply = 4.98904 +15V Supply = 14.9479

-15V Supply = -14.9433 +5V Ref = 5.00092

-5V Ref = -5.00763 No system errors to report Closing the communications port... Program completed.

SWIFT 20 Sensors Software Utilities

TIXFER - Low-Profile Transducer Interface Transfer

This program is used to change settings within the SWIFT Low Profile Transducer Interface (TI). It can be used to read the current settings and save them to the computer (upload) or write the settings to a Low-Profile TI with values from a file on the computer (download).

Syntax The tixfer command requires one argument:

tixfer port

port is the serial port number

1 = COM1: 2 = COM2:

Example

C:\bin>tixfer 1

tixfer $Revision: 1.11 $ ($Date: 1999/04/21 10:12:40 $)

0...exit

1...Upload/Save a chassis

2...Restore/Download a chassis Enter choice? 1 Enter TI box address? 1 Enter output specifications filename? example.cal Enter description? example for uploading settings Allocating box... Initializing box...

File Format The file used with commands contains a header and a list of parameters.

Transducer calibrations can be uploaded and saved individually. If a test needs to be rerun at a later date but the original transducer is not available, another transducer can be used by downloading its calibration information.

The header must be the first thing in the file, and it must be in the form:

[SWIFT]

Following the header is a list of parameter settings. The syntax is:

ParamName=ParamValue

Software Utilities

SWIFT 20 Sensors

TIXFER - Low-Profile Transducer Interface Transfer

CAUTION

The following rules apply:

Tabs and spaces are allowed. The parameters can occur in any order Names are case insensitive. If a parameter name is not recognized, an error

will be reported, and further processing will be stopped. If an error causes the program to abort while downloading, any parameters

prior to the error will have been successfully downloaded because parameters are downloaded as they are read.

Make important files read-only after uploading. After uploading important files, such as those containing calibration data, make them read-only.

If not protected, important data may get overwritten.

Make important files read-only, and make backups of important data.

More about TIXFER

files

Check force and moment output signals after downloading new settings. Downloading new settings may affect Transducer Interface outputs.

After downloading new settings, force and moment output signals should be monitored to check basic system operation.

The files created by TIXFER are plain text files that can be read by Microsoft Notepad or WordPad. In general, use a common extension such as “.cal” to help identify the files, but that is not required. The settings files contain both configuration settings and calibration settings. As a general rule parameters that begin with K are calibration gains and should not be edited. Configuration settings such as the zero algorithm can be changed without affecting the calibration.

Whenever downloading settings, make sure the file is for the transducer connected to the SWIFT Transducer Interface. Usually the filename for the settings contains the serial number for the transducer. If settings for one transducer are used with another they will not be accurate. Because the LowProfile TI is calibrated by itself, calibration settings for a given transducer can be used with any Low-Profile TI, however, some calibration methodologies require the transducer, cable and Low-Profile TI to be used as a calibration set (end-toend calibration).

The serial number in the TIXFER settings file is the serial number of the LowProfile TI that the settings were first uploaded from.

SWIFT 20 Sensors Software Utilities

TIXFER - Low-Profile Transducer Interface Transfer

The bridge and angle zero values will change whenever a zero is activated by pressing the Low-Profile TI front panel zero button. Therefore, after a zero is performed the zero values uploaded will not match those downloaded.

All parameters within the Low-Profile TI have been calibrated. Because the resolution of each adjustable parameter is finite, downloaded values may vary slightly from subsequent uploads and the values uploaded from various units may be different. The downloaded value gets “snapped” to the closest realizable value. The realizable values depend on the resolution and calibration data for the parameter. Normally the gains from the SWIFT automated calibration stand are computed to a higher resolution than the Low-Profile TI is capable of dealing with.

Software Utilities

SWIFT 20 Sensors

TISHUNT - Low-Profile Transducer Interface Shunt

This program is a utility with various functions related to shunts. The SWIFT system includes the ability to connect a shunt resistor across each of the resistive bridges in the transducer. This shunt function can be used as a simple verification that the SWIFT system is working normally. Shunt verification activates the shunts and compares the results to those recorded during calibration. While this does not guarantee the transducer is still in calibration, it provides some level of confidence it is working normally. If the shunt results differ significantly from those recorded during calibration the SWIFT system should be evaluated for possible problems.

Syntax The tishunt command requires one argument, as follows:

tishunt port box port is the communications

1 = COM1: 2 = COM2:

box is the SWIFT-Low-Profile TI communications address

1 = lowest possible address 9 = highest possible address

Example

Initializing box...SWIFT TI Shunt Main Menu

0...exit

1...Read current Shunt values

2...Set the TI shunt tolerance

3...Restore Shunt parameters from a file

4...Scan inputs & outputs with shunts

5...Command a shunt cal

6...Write last shunt measurements to a parameter file

Enter choice:

The Shunt Main Menu options are described in the following paragraphs.

SWIFT 20 Sensors Software Utilities

TISHUNT - Low-Profile Transducer Interface Shunt

Option 0 Use this option to exit the program.

Option 1 Use this option to read the shunt tolerance, the last measured shunt values, the

reference values, and the shunt error status.

Note The shunt error status is not maintained over power cycles, so it is only

valid if the shunt is executed after power is applied. Refer to, “Shunt Error

Status,” on pag e 58 for additional information about shunt error status.

This option asks if you want to save the data in a file. Answer Y or N, and if Y, then supply the file name when prompted. The following is typical of what is displayed when this selection is made:

Reading Shunt parameters from TI... OK Shunt Delta Tol: 10.000% FX1 Ref: 3.935 Measured: 3.934 Error Status: 0 FX2 Ref: 3.932 Measured: 3.932 Error Status: 0 FY1 Ref: 3.937 Measured: 3.930 Error Status: 0 FY2 Ref: 3.929 Measured: 3.930 Error Status: 0 FY3 Ref: 3.932 Measured: 3.932 Error Status: 0 FY4 Ref: 3.931 Measured: 3.932 Error Status: 0 FZ1 Ref: 3.930 Measured: 3.935 Error Status: 0 FZ2 Ref: 3.932 Measured: 3.934 Error Status: 0 Save to a file (y/n)?

Note If you save to a file, the file is created in the same directory as the tishunt

program. The file name must contain less than 80 characters.

Option 2 Use this to set the shunt tolerance. When selected, the following is displayed:

The Shunt Tolerance specifies how much the measured shunt deltas may deviate from the Ref settings, and still be considered good.

The value is entered as a percentage, where "1.0" would mean 1.0% of the Ref settings.

For example: if the tolerance is 1%, and the Ref setting is 8.0, then the measured delta must be between 7.92 and 8.08 to be considered good.

It is not necessary to reboot the TI when this value is changed, but a Shunt Calibration must be executed to update the Shunt Error Status words.

Also note that a parameter download will overwrite this value. Enter tolerance (in percent):

Software Utilities

SWIFT 20 Sensors

TISHUNT - Low-Profile Transducer Interface Shunt

Option 3 Use this option to restore shunt settings from a file. The file format is the same as

that used in the tixfer program.

Option 4 Use this option to apply a shunt sequentially, reading the eight bridges and six

outputs of the Transducer Interface. Note that this option does not update the shunt measured values or error status. A reading is first made with no shunts applied (displayed as the zeroes data). The remainder of the readings are displayed as delta values from the original readings.

Enter Filename to save data to (the file will be appended): Enter Description: Reading bridges & outputs unshunted

FX1

zeroes:

bridges: 0.000 0.002 0.000 0.000 0.001 0.000 0.001 0.000 outputs: -0.003 -0.006 0.001 0.000 -0.002 0.000

deltas: Shunting FX1

bridges: -3.933 0.000 -0.001 0.002 -0.001 0.001 0.000 0.000 outputs: -9.014 0.031 -0.031 -0.001 -3.246 -0.188

Shunting FX2

bridges: -0.002 -3.929 0.000 0.001 0.000 0.001 0.001 0.001 outputs: -9.198 -0.049 0.026 -0.011 3.259 -0.072

Shunting FY1

bridges: -0.001 0.001 -3.931 0.001 -0.001 0.000 -0.001 0.001 outputs: 0.029 -8.493 -0.145 -3.695 0.024 0.002

Shunting FY2

bridges: 0.000 -0.001 -0.001 -3.930 0.000 0.000 0.000 0.001 outputs: 0.175 -8.322 0.031 0.021 -0.014 -3.647

Shunting FY3

bridges: -0.001 0.001 -0.001 0.000 -3.931 0.001 0.000 -0.001 outputs: 0.005 -8.538 0.163 3.692 -0.016 -0.003

Shunting FY4

bridges: -0.002 0.001 0.000 0.000 0.001 -3.932 -0.001 0.000 outputs: -0.150 -8.271 -0.018 -0.021 0.021 3.712

Shunting FZ1

bridges: 0.000 0.001 0.000 0.000 -0.001 0.002 -3.922 -0.001 outputs: 0.105 -0.010 -7.482 0.129 -2.892 -0.052

Shunting FZ2

bridges: 0.000 -0.001 0.000 0.001 0.000 0.001 -0.001 -3.931 outputs: -0.052 -0.081 -7.021 0.114 2.749 0.049

FX2

FY1

FY2

FY3

FY4

FZ1 FZ2

SWIFT 20 Sensors Software Utilities

TISHUNT - Low-Profile Transducer Interface Shunt

Option 5 Use this option to command a Shunt Cal in the Transducer Interface. This is the

same as pressing the Shunt button on the front panel of the Low-Profile TI. A period is displayed on the screen for every change in the shunt state. This gives you a quick view of the progress.

TI Shunt Cal state 2 TI Shunt Cal state 5 TI Shunt Cal state 7 TI Shunt Cal state 8 TI Shunt Cal state 11 TI Shunt Cal state 14 TI Shunt Cal state 17 TI Shunt Cal state 20 TI Shunt Cal state 23 TI Shunt Cal state 26 TI Shunt Cal state 29 TI Shunt Cal state 32 TI Shunt Cal state 34 TI Shunt Cal state 35 TI Shunt Cal state 38 TI Shunt Cal state 41 TI Shunt Cal state 43 TI Shunt Cal state 44 TI Shunt Cal state 47 TI Shunt Cal state 0 TI Shunt Cal completed. Read results by selecting appropriate menu option.

Option 6 A valid shunt calibration should be performed prior to executing this command.

This option allows an easy means of setting the Shunt Calibration Reference values after calibration. After this option has executed, the file that was written can then be downloaded (using option 3). Downloading the file will set the Shunt Reference values to the last measured values, so that subsequent Shunt Calibrations should pass when the SWIFT system is setup properly, and fail when not setup properly.

Note This menu choice should only be used by qualified service personnel.

Software Utilities

SWIFT 20 Sensors

TISHUNT - Low-Profile Transducer Interface Shunt

Setting Up Shunt Calibration Reference Values

The tishunt utility provides all of the necessary functions for setting up a Transducer Interface with valid Shunt Cal Reference values.

Note This procedure should only be performed by qualified service personnel.

Before running the tishunt utility, connect the Transducer cable and Shunt cables from the SWIFT Low-Profile TI to the SWIFT Transducer Assembly. Power up the SWFT Low-Profile TI and wait for the red Fail indicator on the Low-Profile TI front panel to go out (this indicates that the Low-Profile TI is ready).

Note that it is not necessary to perform a System (Transducer) Zero prior to the Shunt Cal.

Procedure 1. Launch the tishunt utility.

2. Using Option 2, enter the desired shunt tolerance.

3. Using Option 5, command a shunt cal, and wait for it to complete. This causes the Low-Profile TI to apply and measure each shunt delta. These measured values will be written as the Cal Reference values. The Shunt indicator on the Low-Profile TI front panel should not blink (blinking indicates that the shunt cal verification failed).

4. Using Option 1, read the current shunt parameters. It is not necessary to save these to a file. Review the measured values and verify that they are correct.

5. Using Option 6, write the last shunt measurements to a parameter file. This sets up a file that contains the eight Set Shunt Cal Reference commands, with the last measured values as the values for the commands. This step does not download the values, but forces the generation of a shunt cal reference parameter file.

Write down the filename that is generated, as it will be required later.

6. Using Option 3, restore shunt parameters from a file. Enter the filename used in Option 6 (Step 5). The tishunt utility then downloads the shunt cal reference values to the Low-Profile TI. These values are written into nonvolatile memory within the Low-Profile TI, and are automatically restored whenever the Low-Profile TI is powered up.

7. Using Option 5, command another shunt cal, and wait for it to complete. This provides a verification, showing that the values downloaded are valid.

The Shunt indicator on the Low-Profile TI Front Panel should not blink (blinking indicates that the shunt cal verification failed).

SWIFT 20 Sensors Software Utilities

TISETZERO – Low-Profile Transducer Interface Set

TISETZERO – Low-Profile Transducer Interface Set Zero Method

This program allows some configuration settings to be changed in a SWIFT Low-Profile Transducer Interface (TI) without modifying a settings file. This program only changes configuration settings, it does not change any calibration settings.

Syntax :

tisetzero port box [zero_algo]

port is the communications

1 = COM1: 2 = COM2:

box is the Low-Profile TI communications address

1 = lowest possible address 9 = highest possible address

zero_algo is optional and specifies the zero algorithm

0 = lowest 4 = highest

Example

C:\bin>tisetzero 1 1

Firmware Version: 2.6.1 Current angle mode is ENCODER Current zero algorithm is SPINNING BRIDGE AND ANGLE UNLOADED Zero algorithms...

0) exit

1) fixed

2) spinning bridge

3) spinning bridge and angle unloaded

4) spinning 2 point

Enter choice?

Option 0

Use this option to exit the program

Option 1 Use this option for fixed (non-spinning) applications. It sets the AngleMode to 1

(fixed) and the ZeroAlgorithm to 0 (fixed). You may need to set the fixed angle manually.

Software Utilities

Option 2 Use this option for spinning applications. It sets the AngleMode to 0 (encoder)

and the ZeroAlgorithm to 1 (spinning bridge, angle with level).

Option 3 Use this option for spinning applications. It sets the AngleMode to 0 (encoder)

and the ZeroAlgorithm to 3 (spinning bridge and angle)

Option 4 Use this option for spinning applications. It sets the AngleMode to 0 (encoder)

and the ZeroAlgorithm to 4 (2-point bridge and angle with level).

SWIFT 20 Sensors

Error Messages

When a SWIFT utility encounters an error, a traceback message is displayed. An example traceback message is:

serial port command timeout, received: 0 chars, buffer:

-1: (DoTIUploadBox) upload box error

-1: (SwiftTI::Init) error reading typeid

-1: (MParm::ReadVal) error read value for Type ID

-1: (MPort::DoCommand) error sending or receiving response

-4: (MPort::GetResponse) error parsing error code

-4: (ParseErrorCode) expected @

Usually you only need to be concerned with the first line of the traceback which gives a summary of the error. The indented list of messages may provide additional information that in some instances will be helpful to determine the cause of an error. For instance, if the program reported an “out of range” error one of the other lines may indicate the name of the parameter being written to when the error occurred.

Error Messages

The number at the beginning of an indented error line is an error number. Negative error numbers are generated by the SWIFT utility program. Positive error numbers are generated by the Low-Profile TI.

SWIFT 20 Sensors Software Utilities

Shunt Error Status

This is the error status for each bridge from the last shunt cal that was performed. The error status is a bit-mapped status word, where the error is present if the bit is set to 1.

Bit 0 = Bridge amplifier was saturated prior to applying the shunt. Bit 1 = Bridge amplifier was saturated after applying the shunt. Bit 2 = Measured delta value failed high. Bit 3 = Measured delta value failed low. Bit 4 = A procedural error occurred (unable to read a value, etc.). In the following example the error status received is 5 indicating that bits 0 and 2

were set.

Bit 43210 Bit Value168421 Example00101

Error Status=

Software Utilities

SWIFT 20 Sensors

Setting up the Low-Profile Transducer Interface

Important This section includes information related to the Low-Profile

Transducer Interface (TI). Fo r SWIFT transducers designed to operate with the newer Mini TI, there is a separate manual that documents the Mini TI setup (MTS part number 100214316).

Overview Three different software configurations are used by the TI, depending on whether

you will be using the SWIFT sensor on the test track (spinning application) or in the laboratory (non-spinning application). Angular transformation is required on the test track only. If you are using angular transformation, you must define the encoder resolution. If you are using the same transducer and TI for data collection and simulation testing, you must change the software configuration before the TI can be used for simulation testing.

Contents Select a Zero Method 60

Calibration File Elements 61

Zero Algorithms 62 Upload the Calibration File 64 Edit the Calibration File 66 Download the Calibration File 70

SWIFT 20 Sensors Setting up the Low-Profile Transducer Interface

Select a Zero Method

Before you install a transducer and zero it, you must configure the transducer interface (TI) for the appropriate zero method.

Equipment required You will need:

• A laptop computer (at test track) or desktop PC

• Serial port communication cable

• SWIFT Transducer Interface Utilities diskette

• Know the address assigned to each TI box

• Some experience with DOS commands and text editors

Zero methods There are two separate zero algorithm classes used to zero the transducer inputs.

The method you choose depends on whether you will use the transducer in a spinning (test track) application (Zero Algorithm 1, 3 or 4) or non-spinning (road simulator) application (Zero Algorithm 0).

If you are using the same transducer with a road simulator that you used previously on the test track, you must re-zero the transducer using the nonspinning zero algorithm.

When you select an algorithm, you are also enabling the zero button(s) on the front panel of the TI. There are two zero buttons:

Bridge Zero Angle Zero

What you need to do To change the zero algorithm used by the TI you will need to:

1. Copy the original calibration file from the diskette that came with the transducer to the computer.

2. Edit the calibration file to select a zero algorithm and angle mode.

3. Download the modified calibration file from the computer to the TI box.

4. Repeat the process for all of the transducers.

These steps are described in detail in the following sections.

Setting up the Low-Profile Transducer Interface

SWIFT 20 Sensors

Calibration File Elements

[SWIFT] Name=zero 3 after new tire SerialNum=1234567 Normalization=0 InputSwitches=255 OutputPolarities=40 ZeroAlgorithm=4 AngleMode=0 AngleOffset=82.0898 AngleFixed=0 EncoderSize=0 ZFX1=0.103786 ZFX2=-0.023199 ZFY1=-0.094017 ZFY2=-0.184371 ZFY3=-0.225885 ZFY4=-0.269841 ZFZ1=-0.101343 ZFZ2=-0.045177 KFX1=0.196337 KFX2=0.195604 KFY1=0.169231 KFY2=0.166789 KFY3=0.167277 KFY4=0.16801 KFZ1=0.195849 KFZ2=0.196581 KMX=3.7558 KMYX=2.39805 KMYZ=2.5641 KMZ=3.75824 KFXFY=0.000611 KFXFZ=-0.00315 KFXMX=0.008864 KFXMY=-0.005348

SWIFT file identifier

Description of the file

Serial number of the T

ransducer Interface (TI)

Internal calibration for the TI

Polarity of the six outputs

(default = 40)

Zero Algorithm

Angle Mode

Angle Offset

Fixed Angle

Bridge Zeroes

Do Not Modify

Calibration Gains

Do Not Modify

Setting for all input switches

(default = 255, all closed)

S20-33

Encoder Size

The following figure shows some elements of the calibration file:

Select a Zero Method

SWIFT 20 Sensors Setting up the Low-Profile Transducer Interface

Typical Calibration File

Select a Zero Method

Items you may edit • OutputPolarities–defines the polarities of the six outputs. Change these

only if your application requires different polarities from those on the transducer label.

• ZeroAlgorithm–selects a zero algorithm for the application.

• AngleMode–selects the mode used for determining the encoder sine and

cosine.

• AngleFixed–used for non-spinning applications.

• AngleOffset–used for spinning applications. Normally you do not need to

change this value.

• EncoderSize–defines the size of the encoder. The value will typically be 1

for the spinning slip ring.

• Zero Algorithms

The following table lists the different values available and the angle zero and bridge zero functions that they perform:

Zero Algorithm Values Defined (p art 1 of 2)

Zero Algorithm When to Use Bridge Zero Angle Zero

Use this algorithm for non-spinning (road simulator) applications.

When you press the Bridge Zero button, the TI measures the static transducer bridge offsets. It sets up zero DACs

The Angle Zero button is nonfunctional.

to provide 0.0 V raw bridge

(AngleMode=1)

output. The Bridge Zero LED will

light for 3–4 seconds, and will go off when the zero process is complete.

This is the algorithm for spinning (test track) applications.

When you press the Bridge Zero button, the TI will collect one revolution of raw bridge data, average the data, and remove the DC offset by

You will need to mechanically level

setting the zero DACs to the average value.

the SWIFT sensor.

The Bridge Zero LED will

The transducer is unloaded during the zero process.

(AngleMode=0)

light continuously until the wheel is turned for one revolution (index-to-index). After one revolution of data is collect, it will flash (at approximately 4 Hz) for 30 seconds while the bridge zero values are computed.

When you press the Angle Zero button, the TI will read the current angle and use the value to set the angle sum to 0.0 degrees.

The Angle Zero LED will light for a few seconds while the TI sets the angle offset value.

If you do not press the Angle Zero button, the value for AngleOffset will not be updated in the calibration file.

The wheel must be rotated past the encoder index pulse at least once after power up so that the electronics can determine the absolute angular position.

Reserved for future use.

Setting up the Low-Profile Transducer Interface

N/A N/A

SWIFT 20 Sensors

Zero Algorithm Values Defined (p art 2 of 2)

Zero Algorithm When to Use Bridge Zero Angle Zero

Select a Zero Method

Use this algorithm if you do not need to mechanically

Both the Angle Zero and Bridge Zero buttons are functional. This algorithm will perform both angle zero and bridge zero processes

when either of these buttons is pressed. level the SWIFT sensor

The transducer is unloaded during the zero process.

(AngleMode=0)

In the Bridge Zero process,

the TI will average the data

and remove the DC offset by

setting the zero DACs to the

average value.

In the Angle Zero process, the TI will collect one revolution of raw bridge data, perform a peak/valley analysis via sine curve fit for X1, X2, Z1, Z2, and determine the angle that will result in positive Z facing upward.

This process assumes that the wheel is hanging, so that the peak vehicle Z axis is read 180° out of phase (transducer peaks are the weight of the wheel, in a downward direction). The angle determined is then shifted by 180°.

This is the recommended

Both the Angle Zero and Bridge Zero buttons are functional. This

algorithm will perform both angle zero and bridge zero processes. algorithm for spinning applications.

You will need to mechanically level the SWIFT sensor

The Bridge Zero button is pressed when the Z beam is facing up.

The Angle Zero button is pressed after the sensor is rotated 90° in

either the plus or minus direction.

Using the data collected from these two positions, all bridge zeros and

angle zeros are computed. The transducer is

unloaded during the zero process.

(AngleMode=0)

SWIFT 20 Sensors Setting up the Low-Profile Transducer Interface

Upload the Calibration File

A unique calibration file was loaded into the TI RAM by MTS before the transducer and transducer interface were shipped. Use the program TIXFER to retrieve the calibration file. TIXFER is a simple DOS-based program that will prompt you for information.

1. Connect a communication cable from the laptop computer or PC to the TI.

2. Insert the SWIFT Transducer Interface Utilities diskette into the lapto p computer or PC.

3. Go to a DOS shell and run the program TIXFER. When you type in the command to run the program, you must specify the

communications port for data transfer. For example, enter TIXFER 1 to specify COM1.

4. Enter 1 at the prompt to upload the calibration file. (See the illustration below.)

5. Enter the address for the TI box at the prompt. The address for the TI is determined by the setting of the address selector

switch on the front panel. If you are using more than one transducer, each TI will have a different address.

6. Enter a file name. The file name must use the DOS naming convention (xxxxxxxx.xxx).

7. Enter a description of the file. You may enter the serial number of the transducer or descriptive words to

help you identify the correct calibration file.

Setting up the Low-Profile Transducer Interface

SWIFT 20 Sensors

Upload the Calibration File

8. TIXFER will prompt you when the file has uploaded.

tixfer 1.7 beta ((10/25/04)

0...exit

1...Upload/Save a chassis

2...Restore/Download a chassis

Enter choice? 1

Enter TI box address? 1 Enter output specifications filename? demo.cal Enter description? demo upload Allocating box... Initializing box... Uploading box... Saving settings... completed upload.

SWIFT 20 Sensors Setting up the Low-Profile Transducer Interface

Edit the Calibration File

CAUTION

Edit the Calibration File

Do not change any other items in the calibration file. The calibration file contains offset values for all of the bridge outputs.

Changing any of the items other th an those listed in the following procedure will cause your calibration file to be incorrect.

Take care not to change any values except those listed in the following procedure. If your calibration file is incorrectly changed, reload the original file from the diskette provided by MTS.

What you need to

know

Before you make the changes to the Calibration file you will need to know how your system is set up (a spinning or non-spinning configuration) and how you want you data from each sensor formatted (the Output Polarities)

1. Open the calibration file using a text editor.

Setting up the Low-Profile Transducer Interface

SWIFT 20 Sensors

Edit the Calibration File

2. If necessary, edit the value for OutputPolarities. This value sets the polarity states of all six outputs (Mz, My, Mx, Fz, Fy, and

Fx) using the following binary scheme (the default configuration is represented):

Mz My Mx Fz Fy Fx

Bit

22212

Bit Value 32 16 8 4 2 1

Example 1 0 1 0 0 0

= 4010 (default)

For example, if you want to invert Fx and Fy, and Mx and My, (making their polarities opposite those shown on the labeling) you would make the following changes:

Mz My Mx Fz Fy Fx

Bit

2322212

Bit Value 32 16 8 4 2 1

101000= 40 110011

* See the examples in the next table.

(old value)

= 5110 (new value)

SWIFT 20 Sensors Setting up the Low-Profile Transducer Interface

Edit the Calibration File

S20-34

Front

Fz UpFyOut

Aft

Fz Up

Fore

Out

S20-35

Front

Fz Up

Fx Aft

Fore

Fz Up

S20-41

Front

Fx Aft

Fz Up

Fx Aft

Out

Fz Up

Output Polarity Value

Example Output Polarities

Description

Direction of Positive output from load on tire when mounted on left hand side of the vehicle

Direction of Positive output from load on tire when mounted on right hand side of the vehicle

OutputPolarities = 40 Standard Setting from

MTS. Matches the axis orientation on the front cover of the SWIFT.

OutputPolarities = 51 Common setting to

alter the axis for-aft and in-out lateral axis

OutputPolarities (left side) = 51 OutputPolarities (right side) = 40

Common setting for vehicle coordinate matching between the two sides of the vehicle.

+Fx = fore +Fy = out from car, left +Fz = up +Mx, +My+, +Mz =

Right-hand rule about Force axis

+Fx = aft +Fy= into car, right +Fz = up +Mx, +My, +Mz =

Right-hand rule about Force axis

+Fx = aft +Fy= into car, right +Fz = up +Mx, +My, +Mz =

Right-hand rule about Force axis

+Fx = aft +Fy = out from car, right +Fz = up +Mx, +My, +Mz = Right-

hand rule about Force axis

+Fx = fore +Fy = into car, left +Fz = up +Mx, +My, +Mz = Right-

hand rule about Force axis

+Fx = aft +Fy = out from car, right +Fz = up +Mx, +My, +Mz = Right-

hand rule about Force axis

3. Perform this step for spinning application. For non-spinning applications, skip to Step 4.

A. Edit the value for ZeroAlgorithm.

The zero algorithm value that you specify will affect the operation of the Angle Zero and Bridge Zero switches.

Set ZeroAlgorithm=1, 3 or 4

B. Edit the value for AngleMode.

Set the AngleMode=0 In this mode, the encoder pulses are summed in with the offset and the

resulting value addresses the sine and cosine RAM, which perform the rotational transformation of the output signals.

1. See the Zero Algorithms discussion on page 62 to help determine which algorithm to use.

Setting up the Low-Profile Transducer Interface

SWIFT 20 Sensors

Edit the Calibration File

C. The AngleOffset value is used when you are operating in encoder

mode (spinning applications). This value is summed with the encoder output count, and used to address the sine and cosine RAM when the angle mode is set to 0 (encoder). Negative angles are converted to their positive equivalent so that the readback value range is 0–360°.

The AngleOffset value is calculated by the TI during the zero process. At the end of the process it is written to the calibration file.

There is no need to change this calculated value.

D. Edit the value for EncoderSize depending on the SWIFT Sensor being

used. For most applications this is EncoderSize=1 (sensor with slip ring option)

4. Perform this step for non-spinning applications. For spinning applications, skip to Step 5.

A. Edit the value for ZeroAlgorithm.

The zero algorithm value that you specify will affect the operation of the Angle Zero and Bridge Zero switches.

Set ZeroAlgorithm=0

B. Edit the value for AngleMode.

Set the AngleMode=1 In this mode, the sine and cosine RAM address is fixed. The encoder is

not used, nor is the encoder offset.

C. Edit the value for AngleFixed.

The AngleFixed value is used for non-spinning applications. This value addresses the sine and cosine RAM when the angle mode is set to 1 (fixed). Negative angles are converted to their positive equivalent so that the readback value range is 0–360°.

You may set the fixed angle value when you are operating in fixed angle mode (non-spinning applications) only if the transducer is rotated from its correct Fz–Fx orientation on the road simulator. For installations where the Fz-Fx orientation on the SWIFT cover(s) is aligned with gravity. The correct setting is:

AngleFixed=0

If the SWIFT is installed at an angle to the desired Fz–Fx output axis, set the AngleFixed value equal to the installed angle offset in degrees, with clockwise rotation positive.

For example:AngleFixed = 45.

5. Save the changes and exit the editor.

SWIFT 20 Sensors Setting up the Low-Profile Transducer Interface

Download the Calibration File

Use the program TIXFER to download the modified calibration file to the TI.

1. Insert the diskette into the laptop computer or PC.

2. Go to a DOS shell and run the program TIXFER. When you type in the command to run the program, you must specify the

communications port for data transfer. For example, enter TIXFER 1 to specify COM1.

3. Enter 2 at the prompt to download the calibration file.

4. Enter the address for the TI box at the prompt. The address for the TI is determined by the setting of the address selector

switch on the front panel. If you are using more than one transducer, each TI will have a different address.

5. Enter the name of the file you wish to download. The file must be in the same directory as the TIXFER program. The file

name must use the DOS naming convention (xxxxxxxx.xxx), which means that you must type the full name and the extension.

6. TIXFER will prompt you when the file has successfully downloaded.

Setting up the Low-Profile Transducer Interface

SWIFT 20 Sensors

7. Enter 0 at the prompt to exit the program.

tixfer 1.7 beta ((10/25/04)

0...exit

1...Upload/Save a chassis

2...Restore/Download a chassis

Enter choice? 2

Enter TI box address? 1 Enter input specifications filename? demo.cal Allocating box... Initializing box... Restoring settings... Downloading box... Completed download.

tixfer 1.7 beta ((10/25/04)

Download the Calibration File

0...exit

1...Upload/Save a chassis

2...Restore/Download a chassis

Enter choice? 0 Program completed

SWIFT 20 Sensors Setting up the Low-Profile Transducer Interface

Download the Calibration File

Setting up the Low-Profile Transducer Interface

SWIFT 20 Sensors

Installing the Transducer

Important This section includes information related to the Low-Profile

Transducer Interface (TI). Fo r SWIFT transducers designed to operate with the newer Mini TI, there is a separate manual that documents the transducer installation with the Mini TI (MTS part number 100214316).

The SWIFT sensor can be installed on a vehicle at the test track or on an MTS Series 329 Road Simulator in the test laboratory.

Contents Test Track Vehicle for Slip Ring Sensor 74

Attaching SWIFT Components to the Wheel Assembly 77 Attaching SWIFT and Wheel Assembly to the Vehicle 80 Installing the Low-Profile Transducer Interface Electronics 82 Setting up the SWIFT Sensor for Data Collection 85 Verifying the Quality of the Zero Procedure 95 Collecting Data 98 Road Simulator 100 Attaching SWIFT Components to the Fixturing 102

Zeroing the Low-Profile Transducer Interface 105 Communication Configurations 106 Cable Configurations 108

Transducers Designed to Operate with a Low-Profile TI but Using a Mini TI

For SWIFT transducers designed to operate with a Low-Profile but are using the Mini TI, an adapter cable is needed; MTS part number 100224052. The transducer and shunt cables are connected to one end of the adapter cable and the other end is connected to J3 of the Mini TI.

SWIFT 20 Sensors Installing the Transducer

Test Track Vehicle for Slip Ring Sensor

Equipment required This procedure requires one person. To install the SWIFT 20A or SWIFT 20T

slip ring sensor, you will need the following equipment:

• Hub adapter (see next figure)

• Modified rim (see next figure)

• Anti-rotate assembly (including customer-supplied mounting arm)

• Small set of hex-head wrenches (both English and metric)

• Tube bender for the anti-rotate bar

• Tube cutter

• Metric socket head drive set (up to 14 mm) with extension

• 5/16-18 UNC tap

• Molykote g-n paste (MTS part number 011-010-207)

• Bolts

For SWIFT 20A Transducer

40 size M8 X 1.25 mm 8 size M5 X 0.8 mm lug nuts

For SWIFT 20T Transducer

32 size M10 X 1.5 mm 12 size M8 X 1.25 mm 8 size M5 X 0.8 mm Lug nuts

• Torque wrenches, capable of the following ranges:

14–28 N•m (10–20 lbf•ft); 28–54 N•m (20–40 lbf•ft), 81–136 N•m (60-100 lbf•ft); 7 N•m (60 lbf •in)

Installing the Transducer

• Cables (transducer and BNC, plus customer-supplied from transducer

interface to data recorder). If the SWIFT is designed to operate with the Low-Profile TI and you have a Mini TI, you will need an adapter cable, MTS part number 100224052.

• Tie wraps

• Data recorder

SWIFT 20 Sensors

Test Track Vehicle for Slip Ring Sensor

S20-57

Modified Rim

Hub Adapter

Transducer

Slip Ring

Bracket

Slip Ring

Encoder

CAUTION

• 12 V power supply (for example, a car battery)

Slip Ring Installation Components (Test Track)

Importance of bolts Bolts provide exceptional clamp force at the transducer to rim/spindle interface.

• Bolts on the inner hub secure the hub adapter to the SWIFT sensor.

• Bolts on the outer ring secure the SWIFT sensor to the wheel rim (or road

simulator spindle adapter).

Note Make sure all bolts are in place and fully torqued during all tests.

Correct use of bolts reduces the safety hazard and ensures optimal transducer performance.

Before you begin Observe the following safety conditions while you are attaching the SWIFT

sensor and components to the vehicle.

Do not pressure-wash the transducer or clean it with solvents that would degrade its silastic seal.

Pressure-washing the transducer or cleaning it with certain solvents can damage it or degrade its silastic seal.

Avoid pressure-washing the transducer. Use only solvents that will not degrade the silastic seal.

Do not use high-pressure-air to clean debris from around the transducer connectors.

High-pressure-air can damage the silastic seals.

Use a fine wire brush and low air-pressure [0.07 MPa (10 psi)] to clean debris from around the transducer connectors.

SWIFT 20 Sensors Installing the Transducer

Test Track Vehicle for Slip Ring Sensor

CAUTION

Do not lay the wheel flat while the transducer is attached to it. When the wheel is laid flat with the transducer facing down the weight of the

wheel can damage the connectors.

Always hold the wheel upright when the transducer is attached to it. If needed, have another person hold the tire upright while you tighten the bolts, or place the wheel on a thin layer of foam to protect the connectors.

Do not under-torque the lug nuts. Lug nuts that are not properly tightened can become loose during testing.

Loss of a wheel can cause damage to the test vehicle and transducer and result in injury to personnel.

Always tighten the lug nuts to the torque rating recommended for the vehicle/ wheel.

Do not drop the slip ring bracket (spider). Dropping the slip ring bracket can damage the slip ring or a connector.

Always use care when you handle the slip ring bracket.

Do not allow the mounting arm or anti-rotate arm to bump against any portion of the wheel or wheel well.

The anti-rotate device should not bump against the wheel well or other vehicle parts at any time. Any jarring of the anti-rotate arm will damage the slip ring and/or the encoder.

Position the mounting arm and anti-rotate assembly so that full suspension travel will not cause interference with the wheel well or any other part of the vehicle.

Installing the Transducer

SWIFT 20 Sensors

Test Track Vehicle for Slip Ring Sensor

Attaching SWIFT Components to the Wheel Assembly

SWIFT 20 Fasteners

SWIFT 20A SWIFT 20T

M8 X 1.25 mm M10 X 1.5 mm M5 X 0.8 mm M8 X 1.25 mm

M5 X 0.8 mm

MTS modified M12 X 1.5 mm or 1/2–20UNF inch lug nuts

* For threaded spindle applications, customer supplied M12 or 1/2 in

fasteners of appropriate length and thread pitch are required.

MTS modified M12 X 1.5 mm

or 1/2–20UNF inch lug nuts

Procedure 1. Remove the current wheel from the test vehicle.

2. Clean all surfaces of the vehicle tire(s) and the modified rim(s). It is critical that all surfaces be free of stones, burrs, and grease. Use a mild detergent such as dish soap.

Important It is imperative that the mounting surfaces of the transducer be

protected from getting scratched. Any wheel components and work surfaces that might come in contact with the transducer must be clean, smooth, and free of debris

Mount the tire(s) on the modified rim(s).

3. Wipe the unpainted mating surfaces of the modified rim and the transducer with a clean dry cloth.

4. Attach the transducer to the modified wheel rim. Hand tighten the bolts. If environmental conditions warrant, coat each fastener with Birchwood

Casey Sheath RB1 rust preventative (or equivalent).

Lubricate the threads and under the heads of all fasteners, using Molykote g-n paste.

SWIFT 20 Sensors Installing the Transducer

Test Track Vehicle for Slip Ring Sensor

SWIFT 20T

Viewed from Pilot Side

Rim Pilot

Tabs (8)

SWIFT 20A

Viewed from Pilot Side

Rim Pilot

Tabs (8)

S20-16

1418

235

Inner Bolt Pattern

All bolts are M8

Outer Bolt Pattern

All bolts are M8

Inner Bolt Pattern

Bolts 14 are M8.

Bolts 520 are M10

Outer Bolt Pattern

Bolts 18 are M8.

Bolts 924 are M10

5. Attach the hub adapter to the transducer. Hand tighten the bolts If environmental conditions warrant, coat each fastener with Birchwood

Casey Sheath RB1 rust preventative (or equivalent). Lubricate the threads and under the heads of all fasteners, using Molykote

g-n paste. A clearance of approximately 0.05 mm (0.002 in) is required between the

transducer and the hub adapter. You should not have to wedge the wheel into the rim or the hub adapter into the SWIFT sensor.

Installing the Transducer

Bolt Torque Sequence

SWIFT 20 Sensors

Test Track Vehicle for Slip Ring Sensor

6. Tighten the mounting bolts. A. Following the sequence shown in the previous figure for the transducer

being installed, torque the inner hub bolts in two increments, as shown in the following table.

Important For the SWIFT 20T, the M8 bolts in the inner bolt pattern (bolts 1–4

in the previous figure) must be torqued, as described, before torquing the M10 bolts (bolts 5–20 in the previous figure).

Note To minimize negative clamping effects, you must torque the bolts in the

sequence shown.

Torque Increment SWIFT 20A SWIFT 20T

Bolt Size M8 M8 M10

1st Increment 14 N•m (10 lbf•ft) 14 N•m (10 lbf•ft) 27 N•m (20 lbf•ft)

Final Torque 27 N•m (20 lbf•ft) 27 N•m (20 lbf•ft) 54 N•m (40 lbf•ft)

B. Following the sequence shown in the previous figure for the transducer

being installed, torque the outer hub bolts in two increments as shown in the previous table.

Important For the SWIFT 20T, the M8 bolts in the outer bolt pattern (bolts 1–8

in the previous figure) must be torqued, as described, before torquing the M10 bolts (bolts 9–24 in the previous figure).

Note To minimize negative clamping effects, you must torque the bolts in the

sequence shown.

SWIFT 20 Sensors Installing the Transducer

Test Track Vehicle for Slip Ring Sensor

Attaching SWIFT and Wheel Assembly to the Vehicle

1. Before installing the SWIFT and wheel assembly, attach the slip ring antirotate bracket to the vehicle.

Since the bracket is unique to each vehicle the slip ring anti-rotate bracket must be provided by the customer. The following are guidelines for manufacturing and locating the bracket. See the next figure.

• The bracket must be stiff, preferably steel or stiff aluminum tubing, so

as not to move or rotate when connected to an unsprung mass or spindle which will allow the slip ring assembly to move with the tire as the vehicle is moving or testing.

• The bracket must be positioned so as not to hit the fender at the

extreme end of the suspension travel.

• The bracket must maintain a minimum clearance from the tire so as not

to hit the tire when it is loaded and rotating.

2. Attach the wheel/transducer to the test vehicle. Lubricate the lug bolt threads with Molykote g-n paste. Tighten the lug nuts to the torque rating recommended for the wheel.

3. Attach the slip ring bracket (spider) and slip ring to the transducer. A. The slip-ring bracket fits over the 10-pin connectors on the front of the

transducer at the locations labeled Board A and Board B. The slip-ring bracket is similarly labeled to prevent connecting it the wrong way.

Note Use care when installing the slip-ring bracket. The 10-pin connectors are

keyed. The slip-ring bracket should be fitted on straight (without bending or angling it) to make sure it engages both connectors simultaneously and evenly.

B. Lubricate the threads and under the bolt heads of the eight M5 X 0.8

mm bolts with Molykote g-n paste. Insert them through the mounting hole in the slip ring bracket and thread them into the transducer. T orque them to 6.8 N•m (60 lbf•in).

C. Make sure that the covers on the shunt connectors are securely locked

in place. Each cover should be twisted until it snaps into the retaining groove.

4. Attach the anti-rotate assembly to the anti-rotate bracket (installed earlier) and the slip ring. If this is the first time the anti-rotate assembly is used on this vehicle or if the mounting location has changed, perform Steps A and B, otherwise proceed to Step C. (Refer to the next figure for guidelines.)

Installing the Transducer

A. Weld the steel tube sleeve to the customer-supplied customer supplied

anti-rotate bracket.

B. Bend the aluminum tube to fit over the wheel.

SWIFT 20 Sensors

Test Track Vehicle for Slip Ring Sensor

Slip Ring

Assembly

Dependent on

Slip Ring/Encoder

Geometry

Slip Ring

Assembly

Suspension/

Unsprung Mass

Minimum Clearance

Typically approximately

6 mm (0.25 in) depending

on tire uniformity. Tire

must not hit bracket when

loaded or rotating.

Anti-Rotate Bracket

must be Stiff (preferably steel

or stiff aluminum tubing), so as

not to move or rotate when

connected to unsprung mass

or spindle, which will allow the

slip ring assembly to move with

the tire as the vehicle is

moving or testing.

Center line

of Wheel

Anti-Rotate

Assembly

6-32 X 1/4 in long

Socket Head

Cap Screw

Transducer

5/16-18 UNC

Low-head Socket Screw

19 mm (0.75 in) long

Steel

Sleeve

Modified Delrin Ball

15.875 mm (0.625 in) diameter

Vehicle Fender

Bracket must not hit

fender at extreme end

of suspension travel

Weld steel sleeve to

anti-rotate bracket

when assembly is

mounted on vehicle

S20-18

Anti-Rotate

Assembly

M4 X 0.7 mm

X10 mm long

or 8-32 X 3/8 in long

Socket Head

Cap Screw (qty 2)

Transducer

Output Cable

C. Measure, making bends as necessary, and cut the aluminum tube to

size. MTS provides an extra long tube with a hinge welded at one end. After

fitting the tube to your test vehicle, cut off the excess length. D. Tap the end of the aluminum tube 5/16-18 UNC X 1.00 inch deep. E. Insert the low-head cap screw through the delrin ball. F. Insert the aluminum tube into the steel sleeve. G. Tighten the screws that attach the hinge joint to the slip ring assembly.

5. Attach the transducer output cable to the slip ring encoder connector and the Slip Ring D-connector on the rear of the TI.

6. Secure the cable along its length so that ot will not become damaged during data collection. (For example, tape it to the external mirror.)

Be sure to leave enough slack in the cable to allow for the full range of wheel travel (jounce and steer).

SWIFT 20 Sensors Installing the Transducer

Test Track Vehicle for Slip Ring Sensor

Installing the Low-Profile Transducer Interface Electronics

Important This section includes information related to the Low-Profile

Transducer Interface (TI). Fo r SWIFT transducers designed to operate with the newer Mini TI, there is a separate manual that documents the Mini TI (MTS part number 100214316).

The Transducer Interface (TI) electronics should be securely fastened to the vehicle in a protected location. The TI box is designed to withstand the accelerations associated with the body of a vehicle during rugged durability and typical data acquisition testing.

The TI box can be located anywhere in the vehicle that is convenient. However, if the TI is able to bounce around during data collection, it can bump against another piece of equipment, pushing in the Zero button. If the Zero button is pushed, you will lose all of the data.

Considerations Suitable locations for the TI box include the vehicle trunk, flatbed, interior floor,

or rear seat. Consider the following guidelines when you fasten the TI box(es) to the vehicle:

• Mount the TI box in a position on or in the vehicle that is protected from

impact and high acceleration events.

• Do not expose the TI box to rain, snow, or other wet conditions.

• Orient the TI box horizontally.

• Multiple TI boxes may be rigidly attached to each other using optional

mounting straps.

• Place a thin foam or rubber material between TI boxes and any hard

mounting surface.

• Use ratcheting straps to provide a tight connection that will not loosen or

untie during testing.

• Do not use rubber cords to secure the TI box because they may stretch and

lose retention in the cord due to inertial forces.

Procedure 1. Connect all data cables from the TI to the data recorder.

There is one cable per channel of data from the TI to the data recorder. These correspond to the three forces, three moments, and angular position.

Note Make sure that there is no tension or strain in the cables or at the cable

and connector junction. There should be some slack in the cables to ensure that they are not pulled during testing.

Installing the Transducer

2. Connect the TI and the data recorder to a 12 V DC power source (such as a vehicle battery).

SWIFT 20 Sensors

Test Track Vehicle for Slip Ring Sensor

Ground to vehicle frame

12 Vdc

Transducer Interface

S50-025

Data Recorder

Ground to vehicle frame

12 Vdc

Transducer Interface

S50-026

Data Recorder

Note Some data acquisition systems may introduce electrical noise spikes to

the battery and cabling. The TI electronics should always be used with the cleanest power supply possible. To reduce the likelihood of noise spikes from the data recorder, we suggest running the power cables in parallel, as shown in the following diagrams. If this does not remove the noise spikes, separate batteries may be required.

3. Ground the TI and data recorder to the vehicle frame. (See the following figures.)

Suggested Grounding for a single TI Box

Suggested Grounding for a Multiple TI Boxes

4. Secure the TI box so that it will not move during data collection.

Note If the TI box is not properly secured, it can bump against another piece of

equipment or a hard surface, pushing in the Zero button. If the Zero

SWIFT 20 Sensors Installing the Transducer

button is pushed, you will lose all of the data.

Test Track Vehicle for Slip Ring Sensor

5. Verify that the shunt contacts are covered. Make sure that the plugs on the slip ring bracket (spider) cover are in place

so that no water will enter the contacts. Make sure that the bayonette covers on the shunt connectors are securely

locked in place. Each cover should be twisted until it snaps into the retaining groove.

6. Turn on the TI and let it warm up for 15-20 minutes before you zero the strain gage bridges.

Installing the Transducer

SWIFT 20 Sensors

Test Track Vehicle for Slip Ring Sensor

CAUTION

Setting up the SWIFT Sensor for Data Collection

Important This section includes information related to the Low-Profile

Transducer Interface (TI). Fo r SWIFT transducers designed to operate with the newer Mini TI, there is a separate manual that documents the Mini TI (MTS part number 100214316).

To ensure accurate data collection, complete this setup procedure daily before you begin testing.

The accuracy of the data that you collect depends on the ability of the SWIFT electronics to “zero out” the forces and angles present in an initial, unloaded state. During the Zero process, the TI box reads the transducer bridge values and compensates for any offsets so that the bridge output is 0 at 0.0 V. It also reads the current angle and compensates for any offset from the Z axis facing up.

You can ensure the success of the Zero procedure by taking these simple precautions:

Considerations for

rotating a tire

Do not introduce extraneous forces or excessive accelerations into the wheel while rotating it during the Zero process.

Any forces applied to the wheel, tire, rim, spider, or outer portion of the transducer will cause a Bridge Zero error.

Make sure to apply only a gentle force at a steady rate to the inner hub while rotating it.

Do not touch or bump the wheel while the transducer is zeroing. T ouching or bumping the wheel will add loads to the transducer, resulting in

an erroneous zero reading.

Avoid all contact with the wheel while the transducer is zeroing. If you suspect that the zero process is incorrect, begin again

When using a zero method that collects zero data while the sensor is rotating (i.e., algorithm 1 or 3), you must be careful to minimize the forces that are induced in the transducer’s bridges.

SWIFT 20 Sensors Installing the Transducer

Test Track Vehicle for Slip Ring Sensor

When using one of these zero methods, never rotate the tire directly, or by grabbing the outer diameter of the transducer. This will introduce forces into the transducer bridges that will result in a bad zero process and unreliable data.

• Rotate the tire at an even rate to avoid accelerations on the transducer.

• For positive-lock differentials, turn the other tire on the axle to cause the

desired rotation in the transducer you are zeroing.

• If you must touch the transducer to rotate the tire, carefully rotate the tire by

touching only the inner diameter of the transducer.

Choosing a Zero

method

Preferred method—Zero Algorithm 4 is the pr eferred method for configuring the calibration file for spinning applications:

ZeroAlgorithm=4 AngleMode=0

This zero method samples all eight input bridges at two positions. After the data is taken, all eight input channels are analyzed for signal offsets, and bridge zeroes and angle zeroes are set in the TI.

Alternate methods—Zero Algorithm 1 and 3 are alternate methods for configuring the calibration file:

ZeroAlgorithm=1 AngleMode=0

Zero Algorithm 1 samples all eight input bridges on every encoder tick, for one complete revolution. After the data is taken, all eight input channels are analyzed for signal offsets, and bridge zeroes are set in the TI. The angle offset is then recorded in a separate step.

ZeroAlgorithm=3 AngleMode=0

Installing the Transducer

Zero Algorithm 3 may be more convenient for some test setups. However, you must take care when using it, because it is susceptible to two types of errors:

• Noise spikes from power. These can be minimized by following the

grounding suggestions illustrated earlier in this chapter.

• Extraneous loads. Be very careful to rotate the wheel only by touching the

inner hub of the transducer or by engaging the axle (for some vehicles, this means putting the vehicle in Park) and rotating the opposite wheel.

Because the SWIFT sensor measures loads applied to the outer edge of the transducer, you should never touch the outer edge while you are spinning the wheel. The rotation speed should be smooth, in order to avoid applying inertial braking moments to the transducer.

SWIFT 20 Sensors

Test Track Vehicle for Slip Ring Sensor

[SWIFT] Name=zero 3 after new tire SerialNum=1234567 Normalization=0 InputSwitches=255 OutputPolarities=40 ZeroAlgorithm=4 AngleMode=0 AngleOffset=82.0898 AngleFixed=0 EncoderSize=1 ZFX1=0.103786 ZFX2=-0.023199 ZFY1=-0.094017 ZFY2=-0.184371 ZFY3=-0.225885 ZFY4=-0.269841 ZFZ1=-0.101343 ZFZ2=-0.045177 KFX1=0.196337 KFX2=0.195604 KFY1=0.169231 KFY2=0.166789 KFY3=0.167277 KFY4=0.16801 KFZ1=0.195849 KFZ2=0.196581 KMX=3.7558 KMYX=2.39805 KMYZ=2.5641 KMZ=3.75824 KFXFY=0.000611 KFXFZ=-0.00315 KFXMX=0.008864 KFXMY=-0.005348

S20-38

Zero Algorithm

0 Non-spinning mode 1 Spinning mode (uses a digital

inclinometer for angle zero and spinning the tire for the bridge zero

process 2 Not used 3 Spinning mode (uses spinning the

tire for both angle and bridge

processes) 4 Spinning mode (use a digital

inclinometer to define two positions

90° apart for the bridge zero and

angle zero processes.

Angle Mode

0 Spinning mode (obtains angle from

the encoder) 1 Fixed angle mode (used for test rigs

in the lab)

This zero method samples all eight input bridges on every encoder tick, for one complete revolution. After the data is taken, all eight input channels are analyzed for signal offsets, and the X and Z input channels are analyzed to determine the angular zero point.

SWIFT 20 Sensors Installing the Transducer

Example of a .cal file

If Zero Algorithm=4 When you zero the TI, you want the vehicle to be fairly level and the transducer

to be as close to plumb as practical.

1. Install the SWIFT sensor(s) and data collection equipment on the vehicle.

2. Connect all cables and turn on the power to the TI boxes.

3. Let the TI boxes and transducers warm up for 15-20 minutes.

4. Run the TISTATUS program to compare the supply voltages to the

5. Verify that the calibration file is set up correctly for your testing application.

reference voltages. Type: TIstatus <port#> <box#> If the supply voltages vary more than 0.5 V from the reference voltages,

there is a power supply problem that must be resolved before you can continue.

Test Track Vehicle for Slip Ring Sensor

Axes Icon

S20-22

A. Download the spinning calibration file (xxxxxs.cal) to the computer

B. If necessary, modify the zero algorithm and angle mode to fit the

C. The EncoderSize parameter should be omitted or set to EncoderSize=1 D. Download the calibration file to the TI box.

Note If it becomes necessary to change the zero algorithm or angle mode

6. Elevate the vehicle with a lift, raise each corner with a jack.

7. Perform the zero procedure on each corner of the vehicle. Use a digital inclinometer to zero the angle and strain gage bridges on the

transducer.

from the MTS Disk that corresponds to the serial number of the transducer that you are setting up.

application/use requirements as described in, “Edit the Calibration

File,” on page 66.

after downloading the file to the TI, you can do so by using the TISETZERO utility, as described in, “TISETZERO – Low-Profile

Transducer Interface Set Zero Method,” on page 56

A. Rotate the tire one full revolution so that the encoder can find the zero

index mark.

Note The encoder has a red dot on the mounting flange connected to the slip-

ring bracket and a black dot on the slip-ring connector housing where it interfaces with the mounting flange. These dots, when aligned next to each other, indicate the index mark is under the encoder sensor.

B. Rotate the tire as necessary, until the Fz on the axes icon (see the next

figure) printed on the transducer label is pointing up

C. Attach the level bracket so that it sits on top of the transducer. Insert the

locking pin through the bracket and into the pin pilot hole on the transducer (see the next figure).

Installing the Transducer

SWIFT 20 Sensors

Test Track Vehicle for Slip Ring Sensor

Digital Inclinometer

in this position

should read 0°, ±0.1°

Insert Lock Pin

in Pilot Hole

Level Bracket

S20-20

0.00°

Axes Icon

Digital Inclinometer

(alternate location)

in this position

should read 90°, ±0.1°

S20-21

Angle Zero

Switch and Indicator

Bridge Zero

Switch and Indicator

Note If the anti-rotate assembly interferes with the mounting of the digital

inclinometer, use the alternate mounting location shown.

D. Place the digital inclinometer on the bracket and rotate the tire until the

inclinometer reads 0.0°, ±0.1° (or 90.0°, ±0.1° if the alternate position is used).

E. Push the Bridge Zero button on the front of the TI box. The LED will

turn on for a few seconds, then start blinking rapidly. The Angle Zero indicator will start blinking slowly.

F. Remove the digital inclinometer and level bracket. G. Rotate the tire 90° in either direction. H. Attach the level bracket so that it again sits on top of the transducer.

Insert the locking pin through the bracket and into the pin pilot hole on the transducer.

SWIFT 20 Sensors Installing the Transducer

Test Track Vehicle for Slip Ring Sensor

Digital Inclinometer (alternate location)

in this position

should read 90°, ±0.1°

Digital Inclinometer

in this position

should read 0°, ±0.1°

Insert Lock Pin in

Pilot Hole

Level Bracket

S20-23

0.00°

Rotate

Transducer

+ or  90°

I. Place the digital inclinometer on the bracket and rotate the tire until the

inclinometer reads 0.0°, ±0.1° (or 90.0°, ±0.1° if the alternate position is used).

If Zero Algorithm=1 When you zero the TI, you want the vehicle to be fairly level and the transducer

J. Push the Angle Zero button on the front of the TI box. The Angle Zero

indicator will light for a few seconds, then both the Bridge Zero and Angle Zero indicators should turn off.

Note If the red Fail indicator lights momentarily and the Bridge Zero and

Angle Zero indicators end up blinking slowly, problems were detected

with the zero. Try repeating the procedure. Use TISTATUS for a more detailed explanation of the problem. If you continue to have an error, consult the chapter, “Troubleshooting,” on page 127.

K. Rotate the transducer slightly to update the rotational transformation.

At this point the TI should be reading absolute forces in the vehicle

coordinate system. L. Perform, “Verifying the Quality of the Zero Procedure,” on page 95. M. Look at your data acquisition system to verify that the SWIFT sensor is

gathering data.

to be as close to plumb as practical.

1. Install the SWIFT sensor(s) and data collection equipment on the vehicle.

2. Connect all cables and turn on the power to the TI boxes.

3. Let the TI boxes and transducers warm up for 15-20 minutes.

Installing the Transducer

SWIFT 20 Sensors

Test Track Vehicle for Slip Ring Sensor

4. Run the TISTATUS program to compare the supply voltages to the reference voltages.

Type: TIstatus <port#> <box#> If the supply voltages vary more than 0.5 V from the reference voltages,

there is a power supply problem that must be resolved before you can continue.

5. Verify that the calibration file is set up correctly for your testing application. A. Download the spinning calibration file (xxxxxs.cal) to the computer

from the MTS Disk that corresponds to the serial number of the transducer that you are setting up.

B. If necessary, modify the zero algorithm and angle mode to fit the

application/use requirements as described in, “Edit the Calibration

File,” on page 66.

C. The EncoderSi ze parameter shoul d be omitted or set to EncoderSize=1 D. Download the calibration file to the TI box.

Note If it becomes necessary to change the zero algorithm or angle mode

after downloading the file to the TI, you can do so by using the TISETZERO utility, as described in, “TISETZERO – Low-Profile

Transducer Interface Set Zero Method,” on page 56

6. Put the vehicle on a lift or jack up the corner of the vehicle on which the SWIFT sensor is mounted.

Important Place wheel chocks under the wheels on the ground or otherwise

restrain the vehicle to prevent it from moving.

7. Push the Bridge Zero button. Only the Bridge Zero indicator will light.

8. Gently spin by hand, the wheel on the opposite side of the vehicle for two revolutions. Be careful not to allow the wheel to stop or reverse direction.

This will cause the wheel you are zeroing to spin without load.

Note For rear wheels or wheels where this cannot be done, carefully spin the

wheel to be zeroed by gently contacting only the hub adapter bolted to the SWIFT sensor.

9. Stop spinning the wheel when the Bridge Zero indicator begins to blink at a rate of 4 Hz and continues blinking for about one minute.

The Bridge Zero indicator will then turn off, indicating completion of the Bridge Zero procedure.

10. Perform the Angle Zero procedure. Use a digital inclinometer to zero the angle on the transducer, then rotate the

tire to zero the strain gage bridges. A. Rotate the tire one full revolution so that the encoder will pass the zero

index mark at least once.

SWIFT 20 Sensors Installing the Transducer

Test Track Vehicle for Slip Ring Sensor

Axes Icon

S20-22

Digital Inclinometer

in this position

should read 0°, ±0.1°

Insert Lock Pin

in Pilot Hole

Level Bracket

S20-20

0.00°

Axes Icon

Digital Inclinometer

(alternate location)

in this position

should read 90°, ±0.1°

Note The encoder has a red dot on the mounting flange connected to the slip-

B. Rotate the tire as necessary, until the Fz on the axes icon (see the next

C. Attach the level bracket so that it sits on top of the transducer. Insert the

Note If the anti-rotate assembly interferes with the mounting of the digital

figure) printed on the transducer label is pointing up

locking pin through the bracket and into the pin pilot hole on the transducer (see the next figure).

inclinometer, use the alternate mounting location shown.

Installing the Transducer

D. Place the digital inclinometer on the bracket and rotate the tire until the

inclinometer reads 0.0°, ±0.1° (or 90.0°, ±0.1° if the alternate position is used.

E. Push the Angle Zero button on the front of the TI box. The Angle Zero

indicator will turn on for a few seconds, then turn off indicating that the Angle Zero procedure is complete.

11. After completing the Bridge and Angle Zero procedures, rotate the wheel one full revolution clockwise.

This allows the electronics to locate the index pulse for the encoder.

Note The wheel must rotate one-half revolution in the same direction and then

pass over the encoder index point before data collection is started.

SWIFT 20 Sensors

Test Track Vehicle for Slip Ring Sensor

S20-21

Angle Zero

Switch and Indicator

Bridge Zero

Switch and Indicator

12. Perform, “Verifying the Quality of the Zero Procedure,” on page 95.

13. Look at your data acquisition system to verify that the SWIFT sensor is gathering data.

If Zero Algorithm=3 When you zero the TI, you want the vehicle to be fairly level and the transducer

to be as close to plumb as practical.

1. Install the SWIFT sensor(s) and data collection equipment on the vehicle.

2. Connect all cables and turn on the power to the TI boxes.

3. Let the TI boxes and transducers warm up for 15–20 minutes.

4. Run the TISTATUS program to compare the supply voltages to the reference voltages.

Type: TIstatus <port#> <box#> If the supply voltages vary more than 0.5 V from the reference voltages,

there is a power supply problem that must be resolved before you can continue.

5. Verify that the calibration file is set up correctly. A. Download the calibration file (xxxxx.cal) to the computer from the

MTS Disk that corresponds to the serial number of the transducer that you are setting up.

B. If necessary, modify the zero algorithm and angle mode to fit the

application/use requirements as described in, “Edit the Calibration

File,” on page 66

C. For slip-ring transducers, the EncoderSize parameter should be omitted

or set to EncoderSize=1.

D. Download the calibration file to the TI box.

Note If it becomes necessary to change the zero algorithm or angle mode

after downloading the file to the TI, you can do so by using the TISETZERO utility, as described in, “TISETZERO – Low-Profile

Transducer Interface Set Zero Method,” on page 56

6. Elevate the vehicle with a lift, or raise each corner with a jack.

7. Perform the zero procedure on each corner of the vehicle. Both the angle and bridge zeros are computed by rotating the tire.

A. Push either the Angle Zero or Bridge Zero button on the front of the

TI box. Both indicators will light.

SWIFT 20 Sensors Installing the Transducer

Test Track Vehicle for Slip Ring Sensor

B. Rota te the tire 1 1/4 to 2 revolutions, until the Bridge Zero indicator

C. If the Bridge Zero indicator continues to slowly flash after 2 minutes,

D. Perform, “Verifying the Quality of the Zero Procedure,” on page 95. E. Look at your data acquisition system to verify that the SWIFT sensor is

starts flashing. Follow the guidelines in, “Considerations for rotating a

tire,” on page 85.

or if the red Fail indicator flashes, there is an error in the zero process. Run TIST ATUS to find out more information. Repeat Steps A and B. If you continue to have an error, consult the chapter, “Troubleshooting,” on page 127

gathering data.

Installing the Transducer

SWIFT 20 Sensors

Verifying the Quality of the Zero Procedure

Important This section includes information related to the Low-Profile

Transducer Interface (TI). Fo r SWIFT transducers designed to operate with the newer Mini TI, there is a separate manual that documents the Mini TI (MTS part number 100214316).

Perform the following consistency checks for each SWIFT sensor while the vehicle (or corner) is elevated.

1. Does Fz measure the approximate weight of the tire/rim assembly?

2. Is Fx small (less than 0.1% of the rated load)?

3. What is the variance in Fz (modulation) when the tire is slowly rotated?

4. When the vehicle is on the ground, is the Fz reading approximately equal to the corner weight of the vehicle? (See, “Effect of Zero Reference on SWIFT

Output,” on page 96.)

Acceptable Variations for Fx, Fz Readings

Transducer Model Max Rated Load

(Fx, Fz)

Fx Reading with Vehicle Lifted

Test Track Vehicle for Slip Ring Sensor

Fz Modulation with Vehicle Lifted

SWIFT 20 A (Aluminum) SWIFT 20T (Titanium)

21 kN 0.1% (±15–20 N) 0.2% (20–40 N) 30 kN 0.1% (±25–30 N) 0.2% (40–60 N)

5. Perform a Shunt calibration on each transducer. A. Elevate the vehicle on a lift, or jack up each corner. B. Connect the shunt calibration cables from the Shunt A, Shunt B

connectors on the front of the transducer to the Shunt A, Shunt B connectors on the back of the TI box (see the next figure).

C. Connect the signal cable from the slip ring to the Slip Ring connector

on the back of the TI box.

SWIFT 20 Sensors Installing the Transducer

Test Track Vehicle for Slip Ring Sensor

Connect to

Data Acquisition

System

Shunt B

Shunt A

Board B

Board A

S20-24

D. Press the Shunt button on the front of the TI box, or use option 5 in the

Connect the shunt calibration cables

TISHUNT program. The shunt indicator will light continuously for 30–45 seconds. If the

indicator continues to flash after shunt calibration is complete, the shunt calibration has failed.

Effect of Zero

Reference on SWIFT

Output

6. Verify that the outputs from the TI box matches those on the calibration report.

Use either the TISHUNT or TIXFER program to look at the shunt values of the individual bridges.

The shunt calibration will fail if the measured shunt values are >2% of the reference values that were set at the factory. Typically, the shunt values will vary a maximum of 0.20-0.30 V from the reference values.

Refer to the chapter, “Troubleshooting,” on page 127, for more information on dealing with shunt calibration failures.

When the SWIFT sensor is used in spinning applications, it is important that a correct absolute zero of each strain gage bridge is used to ensure the proper computation and transformation of the transducer outputs to a non-rotating vehicle coordinate system. An error in the absolute zero of each bridge will produce a one-time-per-revolution modulation error in the output signals. To achieve absolute zero of each bridge, the zeroing process must account for the tare weight acting on the transducer.

When the vehicle is lifted and the tire and wheel assembly are suspended, the mass of the tire, rim, outer diameter fasteners, and outer ring of the transducer are all reacted through the beams of the transducer. With gravity acting on this outer tire/rim assembly, the SWIFT sensor measures a vertical force pulling down on the transducer.

Installing the Transducer

The SWIFT output cannot be zero, because it is not possible to set the vehicle on the ground precisely enough that the ground supports only the outer tire/rim weight.

SWIFT 20 Sensors

Test Track Vehicle for Slip Ring Sensor

As the vehicle is set completely on the ground, the output from the SWIFT sensor will read the corner weight of the vehicle from the reference point of the transducer. The output of the SWIFT sensor will be slightly less than the total corner weight of the vehicle, because the SWIFT sensor is inboard of the outer tire and rim assembly, and will therefore not measure the weight of the outer tire and rim assembly.

SWIFT 20 Sensors Installing the Transducer

Test Track Vehicle for Slip Ring Sensor

Collecting Data

Important This section includes information related to the Low-Profile

After you zero the TI, you are ready to collect data.

Note If you turn off power to the TI boxes, the zero values will remain valid, but

1. Spin the wheel twice to ensure that the encoder tick is correct.

Transducer Interface (TI). Fo r SWIFT transducers designed to operate with the newer Mini TI, there is a separate manual that documents the Mini TI (MTS part number 100214316).

the encoder will need to find the index pulse to properly convert the rotating coordinates to stationary coordinates. The transducer outputs will not be correct until this happens.

To reset the encoder, roll the vehicle either forward or backward so that the tire completes at least one revolution. This can be accomplished while driving to the test area, or if the vehicle is on a lift in the garage area, rotate the tire according to the guidelines in, “Considerations for

rotating a tire,” on page 85.

Spinning the wheel after you have completed the zero process will ensure that the encoder is correctly referenced to the index pulse. Otherwise, the data collected during the first revolution will be flawed.

2. Remove the vehicle from the lift or jacks.

3. Secure the connector that attaches the signal cable to the top of the slip ring with high quality duct or electrical tape.

This will prevent dust, dirt, and water from entering the connector and causing wear on the pins and sockets.

4. Verify that the shunt contacts are covered. Ensure that the plugs on the slip ring bracket (spider) cover are in place so

that no water will enter the contacts. Ensure that the covers on the shunt connectors are securely locked in place.

Each cover should be twisted until it snaps into the retaining groove.

5. Perform a final inspection of the SWIFT sensor and the electronics to ensure that everything is secure and the TI is on.

The zero data is saved at the end of each completed procedure. If the TI is off, the zero data will not be lost. However, due to thermal conditions that could affect your data, if the TI is powered off for an extended period of time (such as over night), you must repeat the zero process.

Installing the Transducer

Note Rezeroing the transducer is good practice when thermal changes occur.

Rezeroing the transducer at conditions and temperatures closest to the test conditions will provide a more accurate zero and reduce thermal errors.

6. Turn on the data recorder.

7. Start data collection.

SWIFT 20 Sensors

Test Track Vehicle for Slip Ring Sensor

CAUTION

WARNING

Important Before beginning data collection, read the cautions on the next

page.

Do not allow the SWIFT assembly to bump into any hard surfaces while you are driving the vehicle.

Bumping the SWIFT assembly into hard surfaces such as garage doors, ramps and railings will damage the anti-rotate device, cable, slip ring, slip ring bracket (spider), and transducer.

The SWIFT assembly will protrude approximately four inches (102 mm) from the side of the vehicle. Remember to allow extra space on each side of the test vehicle as you enter and exit areas with possible hazards.

Do not drive through tall grass and brush. Driving through tall grass and brush can damage the cable and tear off the

slip ring.

Avoid areas of the test track with tall grass and brush.

Do not use the SWIFT sensor on public roads. Public use or use on public roads could endanger the public.

Use the SWIFT sensor only on closed courses where the loads and load cycles are recorded and managed within the prescribed limits. Only experienced test vehicle drivers should operate a vehicle with the SWIFT sensor attached

Do not use the SWIFT sensor after excessive loading or load cycles. The SWIFT sensor has a limited load life. Excessive loading or load cycles

could cause a fracture of the transducer, wheel rim, hub adapter, or fasteners and can result in injury or death.

Always be aware of the maximum full scale loads appropriate for your transducer. Upon approaching a prescribed limit, return the transducer with the recorded load cycles to MTS for physical inspection and analysis of the load cycle history

SWIFT 20 Sensors Installing the Transducer

Road Simulator

CAUTION

Road Simulator

Before you begin Angular correction is required on the test track only. If you are using the same

transducer(s) for non-spinning simulation testing you must load the correct software into the TI.

The SWIFT sensor must be attached to the test fixture before the vehicle is mounted.

Clean all surfaces. It is critical that all surfaces be free of stones, burrs, and grease.

Do not pressure-wash the transducer or clean it with solvents that would degrade its silastic seal.

Pressure-washing the transducer or cleaning it with certain solvents can damage it or degrade its silastic seal.

Avoid pressure-washing the transducer. Use only solvents that will not degrade the silastic seal.

Do not use high-pressure-air to clean debris from around the transducer connectors.

High-pressure-air can damage the silastic seals.

Use a fine wire brush and low air-pressure [0.07 MPa (10 psi)] to clean debris from around the transducer connectors.

Do not under-torque the lug nuts. Lug nuts that are not properly tightened can become loose during testing.

Loss of a wheel can cause damage to the test vehicle and transducer and result in injury to personnel.

Always tighten the lug nuts to the torque rating recommended for the vehicle/ wheel.

Installing the Transducer

100

SWIFT 20 Sensors

MTS SWIFT 20 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Technical Support

How to Get Technical Support

Before You Contact MTS

If You Contact MTS by Phone

Problem Submittal Form in MTS Manuals

Preface

Before You Begin

Conventions

Documentation Conventions

Hardware Overview

Spinning Applications (Test Track)

Non-spinning Applications (Simulation Lab)

Construction

Design Features

Coordinate System

Specifications

Calibration

Low-Profile Transducer Interface

Low-Profile TI Front Panel

Low-Profile TI Rear Panel

Induction Power Source

Low-Profile TI Jumpers

Interfacing with RPC

Software Utilities

Introduction

TISTATUS - Low-Profile Transducer Interface Status

TIXFER - Low-Profile Transducer Interface Transfer

TISHUNT - Low-Profile Transducer Interface Shunt

Setting Up Shunt Calibration Reference Values

TISETZERO – Low-Profile Transducer Interface Set Zero Method

Error Messages

Shunt Error Status

Setting up the Low-Profile Transducer Interface

Select a Zero Method

Calibration File Elements

Upload the Calibration File

Edit the Calibration File

Download the Calibration File

Installing the Transducer

Transducers Designed to Operate with a Low-Profile TI but Using a Mini TI

Test Track Vehicle for Slip Ring Sensor

Attaching SWIFT Components to the Wheel Assembly

Attaching SWIFT and Wheel Assembly to the Vehicle

Installing the Low-Profile Transducer Interface Electronics

Setting up the SWIFT Sensor for Data Collection

Verifying the Quality of the Zero Procedure

Collecting Data

Road Simulator