MTS SWIFT 45 User Manual

be certain.

SWIFT® 45 GLP Sensor Product Information

Spinning Wheel Integrated Force Transducer For Medium Trucks

100-214-138 A

Trademark information MTS, SWIFT, T estStar, TestWare, MTS Remote Parameter Control, and RPC 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. All other trademarks or service marks are property of their respective owners.

Proprietary information Software use and license is governed by MTS’s End User License Agreement

which defines all rights retained by MTS and granted to the End User. All Software is proprietary, confidential, and owned by MTS Systems Corporation and cannot be copied, reproduced, disassembled, decompiled, reverse engineered, or distributed without express written consent of MTS.

Software validation and

verification

Publication information

MTS software is developed using established quality practices in accordance with the requirements detailed in the ISO 9001 standards. Because MTSauthored software is delivered in binary format, it is not user accessible. This software will not change over time. Many releases are written to be backwards compatible, creating another form of verification.

The status and validity of MTS’s operating software is also checked during system verification and routine calibration of MTS hardware. These controlled calibration processes compare the final test results after statistical analysis against the predicted response of the calibration standards. With these established methods, MTS assures its customers that MTS products meet MTS’s exacting quality standards when initially installed and will continue to perform as intended over time.

MANUAL PART NUMBER PUBLICATION DATE

100-214-138 A June 2009

Contents

Technical Support 5

Preface 9

Conventions 10

Hardware Overview 13

Overview 14 Spinning Applications (Track or Road) 16 Non-Spinning Applications (Laboratory) 17 Construction 18

Design Features 21 Coordinate System 22 Specifications 24 Calibration 28

Installation 31

Hazard Icons 32 Road and Track Vehicles 33

Attaching SWIFT Components to the Vehicle 38

Attaching SWIFT and Wheel Assembly to the Vehicle 41

Collecting Data 48 Road Simulator 51

Attaching SWIFT Components to the Fixturing 54

Analyzing SWIFT Data 59

The Data 60 Fx Data (Longitudinal Force) 61 Fz Data (Vertical Force) 63 Mx Data (Overturning Moment) 64 My Data (Brake Moment) 67 Acceleration and Braking Events Example 68 Slalom Curve Driving Example 70

SWIFT® 45 GLP Sensors

Contents

Maintenance 71

Transducer 72 Cables 73

Troubleshooting 75

Assembly Drawings 79

Cable Drawings 80 SWIFT 45 GLP Mechanical Drawings 85

Contents

SWIFT® 45 GLP Sensors

Technical Support

How to Get Technical Support

Start with your

manuals

Technical support

methods

The manuals supplied by MTS provide most of the information you need to use and maintain your equipment. If your equipment includes 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 Technical Support in one of the following ways.

www.mts.com The web site provides access to our technical support staff by means of an

onlineform:

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

E-mail tech.support@mts.com

Telephone MTS Call Center 800-328-2255

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

Fax 952-937-4515

Please include “Technical Support” in the subject line.

Outside the U.S. 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:

Before You Contact MTS

Know your site

number and system

number

SWIFT® 45 GLP Sensors

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

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

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

Example site number: 571167

When you have more than one MTS system, the system job number identifies your system. You can find your job number in your order pape rwork.

Example system number: US1.42460

Technical Support

Know information from

prior technical

If you have contacted MTS about this problem before, we can recall your file based on the:

assistance

• MTS notification number

• Name of the person who helped you

Identify the problem Describe the problem and know the answers to the following questions:

• How long and how often has the problem occurred?

• Can you reproduce the problem?

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

problem started?

• What are the equipment model numbers?

• What is the controller model (if applicable)?

• What is the system configuration?

Know relevant

computer information

Know relevant

software information

For 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 where 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 can typically be found in the About selection in the Help menu.

• The names of other applications on your computer, such as:

– Anti-virus software – Screen savers – Keyboard enhancers – Print spoolers

Technical Support

– Messaging applications

SWIFT® 45 GLP Sensors

If You Contact MTS by Phone

A Call Center agent registers your call before connecting you with a technical support specialist. The agent asks you for your:

• Site number

• Name

• Company name

• Company address

• Phone number where you can be reached

If your issue has a notification number, please provide that number. A new issue will be assigned a unique notification number.

Identify system type To enable the Call Center agent to connect you with the most qualified technical

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

• Electromechanical material test system

• Hydromechanical material test system

• Vehicle test system

• Vehicle component 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 for your

• Aero test system

Prepare to perform troubleshooting while on the phone:

• Call from a telephone close to the system so that you can implement

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.

In case Technical Support must call you:

• Verify the notification number.

• Record the name of the person who helped you.

• Write down any specific instructions.

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

SWIFT® 45 GLP Sensors

Technical Support

Problem Submittal Form in MTS Manuals

Use the Problem Submittal Form to communicate problems with your software, hardware, manuals, or service that are not resolved to your satisfaction through the technical support process. The 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 respon se—your feedback is important to us.

Access the Problem Submittal Form:

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

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

form to be e-mailed to MTS)

Technical Support

SWIFT® 45 GLP Sensors

Preface

Before You Begin

Safety first! Before you 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 can result in hazardous conditions that can cause severe personal injury or death, or 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 manuals in paper or

electronic form. You may also receive an MTS System Documentation CD. It contains an

electronic copy of the manuals that pertain to your test system, such as:

• Hydraulic and mechanical component manuals

• Assembly drawings

• Parts lists

• Operation manual

• Preventive maintenance manual

Controller and application software manuals are typically included on the software CD distribution disc(s).

SWIFT® 45 GLP 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 Hazard notices may be embedded in this manual. These notices contain safety

information that is specific to the activity 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 all directions and recommendations. 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 or equipment damage, or could 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. They 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® 45 GLP 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

45 GLP Sensors

Preface

Conventions

Preface

SWIFT® 45 GLP Sensors

Hardware Overview

Contents Overview 14

Spinning Applications (Track or Road) 16 Non-Spinning Applications (Laborator y) 17 Construction 18

Design Features 21 Coordinate System 22 Specifications 24 Calibration 28

SWIFT® 45 GLP Sensors

Hardware Overview

Overview

S45-001

WARNING

Overview

The MTS Spinning Wheel Integrated Force Transducer (SWIFT) sensor 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 on the test track and public roads as well as 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 or public road and on a road simulator. It is available in several sizes and materials to fit various vehicle and loading requirements.

Parts replacement,

disassembly, and care

Driving a vehicle configured in this way on public roads can pose unexpected dangers to pedestrians and other vehicle traffic.

Only authorized, licensed drivers, who are experienced driving a vehicle with SWIFT sensors mounted on it, should be allowed to operate the vehicle on public roads. Drive the vehicle with the SWIFT sensor attached on closed courses only until you have proper experience.

Driving a vehicle with SWIFT sensors mounted on it will change the handling characteristics of the vehicle.

The SWIFT sensor assembly, Transducer Interface box, and the accessory components have no user serviceable parts. These components should not be disassembled other than as outlined in “Troubleshooting” beginning on page 75.

Hardware Overview

SWIFT® 45 GLP Sensors

Overview

CAUTION

Do not disassemble the SWIFT sensor, Transducer Interface (TI) electronics, and accessory components.

The SWIFT sensor, TI electronics, and accessory components are not intended to be disassembled, other than as outlined in “Troubleshooting”.

Disassembling or tampering with these components may result in damage to the sensor, loss of watertight seal, and voiding of the warranty.

• The sensor assembly should be returned to MTS annually for recalibration

and inspection.

• Clean the sensor assembly after each use, as described in Maintenance

beginning on page 71, especially if it is exposed to corrosive or abrasive material, such as salt or sand.

• Read and follow all warnings and cautions affixed to the transducer and in

this manual especially those warnings and cautions that deal with installation, use, inspection and maintenance of the transducer.

The SWIFT sensor assembly should not:

• Be bumped into hard surfaces or objects while driving the vehicle.

• Be driven through grass or brush that is taller than the bottom edge of the

sensor.

• Be exposed to loads that exceed the full scale calibrated ranges, as listed in

“Specifications” on page 24.

• Be used if the integrity of the sealed cover has been compromised or the

warning labels removed.

• Be used if the sensor assembly shows indications of damage (such as dents,

bent slip ring bracket arms, a bent anti-rotate assembly, etc.).

• Be used if any part of the assembly has been modified without explicit,

written authorization from MTS.

SWIFT

45 GLP Sensors

Hardware Overview

Spinning Applications (Track or Road)

S45-002

Spinning Applications (Track or Road)

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. The Transducer Interface (TI), power supply, and data recorder can be located inside the vehicle or in the trunk.

Hardware Overview

Spinning Application (Track or Road)

SWIFT® 45 GLP Sensors

Non-Spinning Applications (Laboratory)

S45-003

Non-Spinning Applications (Laboratory)

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 can be mounted directly in the wheel adapters of the MTS Model 329 Road Simulator. The 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.

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

45 GLP Sensors

Hardware Overview

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.

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

vehicle, it spins with the wheel. It does not spin on a road simulator. 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® 45 GLP Sensors

Construction

Anti-Rotate Mounting Bracket (customer supplied)

Anti-Rotate Assembly

Spindle Adapter Spacer

Transducer Interface Cable

Slip-Ring Bracket

Slip-Ring Extension

Bracket SWIFT 45 Transducer

Slip-Ring

Dual Rim Conguration

Front Rim Conguration

Anti-Rotate Mounting Bracket (customer supplied)

Anti-Rotate Assembly

Spindle Adapter Spacer

Transducer Interface Cable

Slip-Ring Bracket

SWIFT 45 Transducer

Slip-Ring

Tire

Spindle adapter spacer The spindle adapter spacer 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 spindle adapter spacer enables you to maintain the original position of the tire on the vehicle (the tire will not protrude from the vehicle) while the transducer is attached to the vehicle. In addition, the spindle adapter spacer helps minimize brake heat from being transferred to the transducer.

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, integrated into the slip ring assembly, that counts off “ticks” to measure the angular position as the wheel rotates. It 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 used for non-spinning applications.

Anti-rotate device The anti-rotate device is attached to the slip ring and the vehicle’ s suspension (or

SWIFT

45 GLP Sensors

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.

Hardware Overview

Construction

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.

The 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 antirotate device mounting recommendations, refer to the Anti-Rotate Customer/ User Assembly drawing at the back of this manual.

Transducer Interface

(TI)

Additional

components

The 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. 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 that are supplied with your SWIFT sensor transducer data cables, TI power cable, a SWIFT Transducer Interface Utilities CD or disk, and the calibration file. MTS can also provide a 12 V DC or 24 V DC power converter for use in the test laboratory.

Hardware Overview

SWIFT® 45 GLP Sensors

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 outward sensor is machined from a solid, specially forged billet of

high strength 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 minimizes temperature-induced variations in accuracy. The temperature rating for the SWIFT sensor is 125° C (257° F) at the spindle hub.

Construction

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 The SWIFT sensor uses a slip ring rather than telemetry for the transducer output

signals. On-board amplification of the transducer bridges minimizes any slip ring noise contribution.

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 non rotating coordinate system). Linear cross talk is compensated by the TI.

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

the encoder. This angular output can be used to calculate wheel velocity. In nonspinning applications, accelerometers can be integrated into the transducer connector housing.

MTS does not supply any conditioning electronics for accelerometers. Ask your MTS consultant for more information about this option.

SWIFT

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Hardware Overview

Coordinate System

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).

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 (angular) 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.

Hardware Overview

SWIFT® 45 GLP Sensors

Coordinate System

The SWIFT coordinate system is transducer-based, with the origin located at the center of the transducer. Positive loads are defined as applied to the outer ring of the transducer.

• Vertical force (Fz) is positive up

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

• Longitudinal force (Fx) is positive out of the transducer

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”.

SWIFT

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Hardware Overview

Specifications

MEASURED VALUE UNITS TITANIUM

SWIFT 45T (MT)

Max Calibrated Load Ratings

Fx lb (kN) 26,977 120

Fy lb (kN) 10,791 48

Fz lb (kN) 26,977 120

Mx in-lb (kN-m) 247,820 28

My in-lb (kN-m) 265,522 30

Mz in-lb (kN-m) 247,820 28

Noise Level peak to peak (0-500Hz) N8

Maximum usable RPM RPM 2200

Maximum Speed (15 in. rolling radius) mph (kph) 150 240

Max Operating Temperature (measured at the spindle hub)

Shock Resistance, Each Axis G50

SWIFT Environmental Protection Rating IP67

Input Voltage Required VDC 10-28

Input Power Required Per Transducer W6

Output Voltage at Full Scale Calibrated Load V±10

SAE J267 Half Axle Rating lb 8000

SAE Bending Moment Seen on Cell in-lb (kN-m) 206,000 23.3

°F (°C) 257 125

Hardware Overview

SWIFT® 45 GLP Sensors

Specifications

Accuracy

Force

Moment

Hysteresis

Force

Moment

Crosstalk

Force → Force

Force → Moment

Moment → Force

Moment → Moment

Assembly Weight Information

Transducer lb (kg) 23.6 10.7

Washer Plates lb (kg) 9.0 4.1

Slip Ring Assembly lb (kg) 2.0 0.9

% FS 1

% FS 0.5

% FS 1

% FS 1.5

% FS 0.5

HD Steel 19.5x6.75 Modified Rim lb (kg) 92.2 41.8

Modified Lug Nuts (qty. 10) lb (kg) 3.0 1.4

Attached Fast en er lb (kg) 6.8 3.1

Total Weight lb (kg) 136.6 62.0

Reference Weight of Standard Unmodified

19.5 X 6.75 X 5.5 Rim and Lug Nuts lb (kg) 61.0 27.7

Differential Weight lb (kg) 75.0 34.0

SWIFT

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Hardware Overview

Specifications

Minimum Rim Size inch 17.5

Typical Lug Nut Bolt Circle Accommodated mm 165 to 225; 8x275

(8x275 pattern accepts 20mm Studs)

Output Connector Type BNC

Auto Shunt Calibration Internal Shunts

Notes:

• Based on loads at center of transducer.

• Each SWIFT 45 sensor will be calibrated on an MTS calibration machine. MTS provides complete

documentation of calibration values for each serial number SWIFT unit. Unique calibration values are stored electronically and transferred to the transducer interface unit (TI box) shipped with each SWIFT 45.

• Periodic recalibration services can be provided by MTS.

• Rim design is provided by MTS and tested to SAE J267 criteria.

• Proper rim design is essential for optimum performance.

• For applications involving non-listed wheel sizes, contact your MTS application engineer.

• Reference rim weights based on 19.5x6.75 truck rim with 5.5" offset, 10 hole 225mm bolt circle.

Single wheel configuration.

Hardware Overview

SWIFT® 45 GLP Sensors

Trans ducer Center-of-Gravity

North American Transducer Center-of-Gravity and Inertia Specifications

ITANIUM

Specifications

0.0 mm 0.0 in.

26.7 mm 1.05 in.

0.0 mm 0.0 in.

1404 kg·cm2480 lbm·in 2759 kg·cm2943 lbm·in 1404 kg·cm2480 lbm·in

SWIFT

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Hardware Overview

Calibration

Each transducer is calibrated by MTS before shipment. The transducer and 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 TI associated with the transducer is listed at the top of the calibration file. A label with the serial number of the TI box (and the SWIFT sensor with which it was originally calibrated) is attached to the back of each TI box.

The calibration file is loaded into the 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 TI.

At any time afterward, pressing the Shunt button on the front of the 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 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.

Hardware Overview

SWIFT® 45 GLP Sensors

Calibration

When you press the Shunt button, the associated Shunt LED lights. As the TI automatically switches through 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 and error light turns on, indicating that the shunt calibration has failed. For more information on dealing with shunt calibration failures, see the chapter, “Troubleshooting.”

ShuntTolerance=2 FX1ShuntDeltaRef=-1.379 FX2ShuntDeltaRef=-1.386 FY1ShuntDeltaRef=-1.381 FY2ShuntDeltaRef=-1.378 FY3ShuntDeltaRef=-1.382 FY4ShuntDeltaRef=-1.381 FZ1ShuntDeltaRef=-1.380 FZ2ShuntDeltaRef=-1.380 FX1ShuntDeltaMeas=-1.378 FX2ShuntDeltaMeas=-1.386 FY1ShuntDeltaMeas=-1.380 FY2ShuntDeltaMeas=-1.379 FY3ShuntDeltaMeas=-1.382 FY4ShuntDeltaMeas=-1.382 FZ1ShuntDeltaMeas=-1.385 FZ2ShuntDeltaMeas=-1.382

Checking the

calibration

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”.

You can check the calibration of a transducer at any time by pressing the Shunt switch. Subsequent shunt commands compare the current feedback values against those stored in the TI. You may set the tolerance values for each TI by editing the calibration file. See the chapter, “Setting up the T ransducer Interface”, for instructions.

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

SWIFT

45 GLP Sensors

Hardware Overview

Calibration

Hardware Overview

SWIFT® 45 GLP Sensors

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