MTS WIFT Mini Transducer Interface User Manual

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SWIFT® Mini Transducer Interface (TI) Product Information

100-214-316 B

Trademark information MTS, SWIFT, TestWare, RPC, and Remote Parameter Control 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

100-214-316 A June 2009 100-214-316 B December 2011

Contents

Technical Support 5

How to Get Technical Support 5 Before You Contact MTS 5 If You Contact MTS by Phone 7 Problem Submittal Form in MTS Manuals 8

Preface 9

Before You Begin 9

Conventions 10

Documentation Conventions 10

Hardware Overview 13

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

Design Features 18 Coordinate System 19 Specifications 21 Calibration 22 Transducer Interface 24

TI Front Panel 27

TI Rear Panel 28

Software Utilities 29

Introduction 30 TI2STATUS - Transducer Interface Status 31

Description of TI2STATUS Indications 31 TI2XFER - Transducer Interface Transfer 33 TI2SHUNT - Transducer Interface Shunt 35 Error Messages 38

SWIFT® Mini TI

Contents

Transducer Interface Setup 41

USB Driver Installation 42 Select a Zero Method 44

Calibration File Elements 45

Upload the Calibration File 47 Edit the Calibration File 48 Download the Calibration File 52

Installation 53

Transducer Interface Electronics Installation 54 SWIFT Sensor Setup for Data Collection 56 Quality of the Zero Procedure Verification 60 Data Collection 61 Road Simulator 63 Zero the Transducer Interface 64

Alternate zero procedures 67

Maintenance 71

Transducer Interface 71

Troubleshooting 73

Contents

SWIFT® Mini TI

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® Mini TI

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 paperwork.

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® Mini TI

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® Mini TI

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 response—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® Mini TI

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® Mini TI

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® Mini TI

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

Mini TI

Preface

Conventions

Preface

SWIFT® Mini TI

Hardware Overview

Contents Overview 14

Spinning Applications (Track or Road) 16 Non-Spinning Applications (Laborator y) 17 Design Features 18 Coordinate System 19 Specifications 21 Calibration 22 Transducer Interface 24 TI Front Panel 27 TI Rear Panel 28

WEEE The Waste Electrical and Electronic Equipment (WEEE) symbol ( ) means

that the controller and its electronic parts must not be disposed of as unsorted municipal waste. Proper disposal is required by approved electronic waste collection agencies. Customers in the EC region who desire to return an end-oflife controller and its electronic parts are encouraged to contact your local MTS Systems Sales/Service Offices for instructions.

SWIFT® Mini TI

Hardware Overview

Overview

Data

S10-01

Track or Road

Laboratory Simulation

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 various sizes and materials to fit various vehicle and loading requirements.

Transducer Interface

(TI)

Additional

components

Parts replacement,

disassembly, and care

The TI provides power to the transducer and uses previously stored calibration values to convert the raw transducer signals from the bridge outputs and the encoder to three force outputs (Fx, Fy, Fz), three moment outputs (Mx, My, Mz) and an angle or angular velocity 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 to 5 V sawtooth output. The angular velocity full scale can be configured in the calibration file.

Additional components that are supplied with your SWIFT sensor include 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 power supply for use in the test laboratory.

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 73.

Hardware Overview

SWIFT® Mini TI

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.

SWIFT

Mini TI

Hardware Overview

Spinning Applications (Track or Road)

Customer Supplied

Power Supply

Customer Supplied

Data Recorder

Transducer

Interface (TI)

Transducer Signals

Output

Signals

S10-02

(Battery or Vehicle power)

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 securely mounted on a carriage rack. The TI box should be protected against environmental conditions (water and mud splashes and dust), and it should not be allowed to be immersed.

Hardware Overview

Spinning Application (Track or Road)

SWIFT® Mini TI

Non-Spinning Applications (Laboratory)

Power Supply (with 4

connections)

Customer-Supplied

Test Control System

Transducer

Interface (TI)

Transducer Signals

Output

Signals

PC Communication

S10-03

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.

Several of the six loads measured by the transducer directly correlate to the MTS Model 329 Road Simulator inputs.

The same transducers used to collect road data can be mounted directly in the wheel adapters of the MTS Model 329 Road Simulator. For durability testing, the SWIFT sensor can be used for iterations within the RPC process. 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. 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

Mini TI

Hardware Overview

Non-Spinning Applications (Laboratory)

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

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 The SWIFT sensor uses a slip ring 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). Any small amount of cross talk present is compensated by the TI.

Angle/Velocity

information

Angular position and angular velocity outputs are available from the TI when it is used in the spinning mode with the encoder. In non-spinning 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.

Hardware Overview

SWIFT® Mini TI

Coordinate System

Transducer

Interface

Output signals

±10 Volts

Angular

Position

Bridge

Outputs

S10-10

In the transducer, independent strain gage bridges measure forces and moments about three orthogonal axes. The signals are amplified to improve the signal-tonoise ratio. An encoder signal measures angular position, which is used to convert raw force and moment data from the rotating transducer to a vehiclebased coordinate system. The force, moment, and encoder information are 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. If desired, the TI can convert the forces and moments to represent a measurement that is offset from the spindle along the y-axis. A seventh (angular) output is available for tire uniformity information, angular position, or to determine wheel speed (depending on the data acquisition configuration).

Normally, the moments are referenced to the center of the transducer but can be offset to another location such as the center of the rim or tire patch.

SWIFT

Mini TI

Hardware Overview

Coordinate System

+Fz

+Mz

+Fx

+Fy

S10-09

Forces Acting on Rim-side of Transducer

Hub Adapter

Mounting Side

Rim Flange

Mounting Side

+Mx

+My

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

By default, 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) follows the right-hand rule, consistent with Fz and

Fy described above.

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. The coordinate system can be moved along the yaxis by changing the y-axis parameter in the calibration file. For instructions on how to change the coordinate system polarities and offset, see “Transducer

Interface Setup” on page 41.

Hardware Overview

SWIFT® Mini TI

Specifications

Parameter Specification

Physical

Height Width Depth Weight Rack mounting kit

Environmental

Ambient temperature Relative humidity Protection

Transducer Interface

28 mm (1.100 in) 213 mm (8.375 in)

171 mm (6.750 in.)

0.907 kg (32 oz) Optional

0–50 °C (32–122° F) 0 to 90%, non-condensing IP64 (complete dust protection, projected water from all

directions)

Specifications

Power requirements

Input voltage Fuses

Power Consumption

Angular velocity

Encoder limit Processing limit

Time delay (encoder tick to main output stable)

Transd ucer cable length Analog outputs

Voltage

Capacitive load Current

Resolution

10–28 VDC Internal thermal, self-resetting

4 Watts maximum without transducer or encoder 6 Watts typical with transducer and encoder with 12 V DC

input.

2,200 rpm maximum 10,000 rpm maximum

150 µs (typical)

100 ft maximum

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

0.01 µF maximum 2 mA maximum

16-bits

Communications

* 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.

SWIFT

Mini TI

USB 2.0

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 memory by MTS before the transducer is shipped. A copy of the file is also provided on a disk.

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.

Note For SWIFT transducers designed to operate with the previous generation

low-profile TI, shunt cables A and B must be connected prior to performing a shunt check.

Shunt verification Shunt verification is good for verifying the SWIFT electrical system. A shunt

verification that fails should be investigated because the calibration will likely be affected. However, a shunt passing does not guarantee the system load accuracy so other checks should be done to verify load accuracy.

At the end of the calibration process, a shunt check is performed. During a shunt check, 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® Mini TI

Calibration

When you press the Shunt button, the associated Shunt indicators toggle while the shunt is in progress. 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 indicators on the front panel will go off (after several seconds). If any bridge fails the shunt test, the red, fail indicator lights, indicating that the shunt calibration has failed. The fail indicator remains lit until a shunt check passes or until you cycle power off and on. Use the TI2STATUS utility to get more detailed information about the shunt failure.

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

Manual shunt

verification

Example of Calibration File Shunt Data

The above example shows shunt data from the calibration file. This data can be transferred, using the TI2XFER program, from the transducer interface memory to a computer or from a computer to the transducer interface memory. Note that items marked ShuntDeltaMeas are uploaded from memory, but not downloaded from the computer.

For more information on TI2XFER, see the chapter, “Software Utilities”.

You can check the system at any time by pressing the Shunt switch (described earlier). The shunt verification checks a portion of the system by applying an electrical offset at the input. Shunt verification can be used as a troubleshooting tool; failing the shunt verification raises the possibility the system is not calibrated. You can set the tolerance values for each TI by editing the calibration file. For instructions, see “Transducer Interface Setup” on page 41.

SWIFT

Mini TI

Hardware Overview

Transducer Interface

or Angular Velocity signal (+/- 10 V)

Transducer Interface

The 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 most data recorders.

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 TI compensates for cross talk by subtracting cross talk values measured during calibration.

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

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

The 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

• Using an offset matrix to shift the coordinate system along the y-axis

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

and moments into a stationary reference frame

Hardware Overview

SWIFT® Mini TI

Transducer Interface

Coordinate

System

Oset

Matrix

The 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 (θ) or Angular Velocity (ω)

Analog signals The force, moment, and angular velocity signals are output from the TI in the

form of ±10 V acquisition systems.

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.

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

SWIFT

Mini TI

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

Hardware Overview

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.

If using the sawtooth angle output for analysis, care should be taken when setting the data acquisition to avoid filter-induced ringing or attenuation of the sawtooth output.

High-Resolution

Velocity Algorithm

The Mini TI has two algorithms for calculating angular velocity. The high resolution algorithm provides a much cleaner signal, but requires a minimum Mini TI FPGA version of 15. For the high resolution algorithm, the plot below shows the expected ripple of the angular velocity signal as a function of actual angular velocity.

The low resolution velocity algorithm produces significantly larger ripples on the angular velocity signal. These ripples can be reduced by enabling a filter at the input of data acquisition system. For more information on the angular velocity output option, contact MTS.

Communications The TI uses USB 2.0 for communication. The MTS supplied USB drivers must

be installed on each computer you connect to the TI.

Hardware Overview

SWIFT® Mini TI

TI Front Panel

Power button and Indicator and Fail Indicator

Shunt button and Indicators

Zero button and Indicators

J5 USB Connector

J4 I/O Connector

Transducer Interface

Transducer Interface Front Panel

Power button and

Indicator

Shunt button and

indicators

Zero button and

indicators

The power button turns power on and off. Pressing and holding the button turns on power and initializes the TI. During initialization, all indicators turn on momentarily. When initialization is complete, all indicators will turn off with the exception of the green Power indicator.

Pressing this button performs a shunt calibration (shunt cal) of the transducer. You do not need to hold the button in continuously, only until the Shunt indicators light up (indicating that the TI has started the shunt cal). The two indicators will alternately toggle on and off as the TI sequences through the shunt calibration of each bridge.

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.)

A shunt calibration will determine the current delta values by measuring the bridges unshunted and shunted values, and then compare these values to the previously loaded reference values.

If the measured values are outside of an acceptable tolerance the red status indicator under the Power indicator with light.

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.

The zero button is used to zero the transducer inputs. When you press the button, the TI executes the ZeroAlgorithm that you specify in the calibration file (see

“Calibration File Elements” on page 45).

J5 USB connector The USB connector is a standard USB 2.0 type B connector for connection to a

laptop or PC with the correct drivers installed.

J4 I/O connector Not used at this time.

SWIFT

Mini TI

Hardware Overview

Transducer Interface

J3 Transducer Connector

J2 Output Connector

J1 Power Connector

TI Rear Panel

Transducer Interface Rear Panel

J1 Power connector Connect a power cable from the external power source.

J2 Output connector The J2 Output connector provides the conditioned sensor outputs that can be

connected to a data acquisition or test control system.

J3 Transducer

connector

Transducers Designed

to Operate with a Low-

Profile TI but Using a

Mini TI

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

For SWIFT transducers designed to operate with a Low-Profile TI 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.

Hardware Overview

SWIFT® Mini TI

Software Utilities

Contents Introduction 30

TI2STATUS - Transducer Interface Status 31 TI2XFER - Transducer Interface Transfer 33 TI2SHUNT - Transducer Interface Shunt 35 Error Messages 38

SWIFT® Mini TI

Software Utilities

Introduction

The SWIFT utility programs in this distribution are for Win32 Operating Systems (Windows 2000 and 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:

1. Copy it to your computer. For example, create the folder the executables (*.exe) to that folder.

2. Launch Command Prompt

3. Change the working directory to where you copied the executables: This step can be eliminated if you set up the PATH environment variable to

include the directory where you copied the SWIFT utility executables.

4. Type the name of a SWIFT utility program providing the necessary command line arguments, for example: from the TI box. Then select the desired function, for example: to upload settings from the TI box. If no command line arguments are provided the program will display a simple help message. This is helpful if you forget the order of the command line arguments.

ti2xfer to transfer settings to or

C:\bin and drag

Choice 1

cd bin.

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 and Windows XP, the environment variables can be

changed at Start–>Settings–>Control Panel–>System. Click on the Advanced tab, and the Environment Variables button. The path is a system variable. Adding the end of the string will cause Command Prompt to search that directory for applications.

;c:\bin, or whatever directory name you used, to

SWIFT® Mini TI

TI2STATUS - Transducer Interface Status

This program gets status information from the SWIFT Transducer Interface (TI) when the TI has encountered a problem and the red failed indicator is lit. Y ou can use this program to easily interpr et the er ror. For certain errors this program may provide additional information.

Syntax ti2status

The following is an example of the ti2status command report:

Example

C:\bin>ti2status

SWIFT Mini TI status (Version 1.3) Fatal error: NONE

Boot Loader version: 1 FPGA version: 10 Firmware version: 24

Zero: Good Fx1 Shunt: Good

Fx2 Shunt: Good Fy1 Shunt: Good Fy2 Shunt: Good Fy3 Shunt: Good Fy4 Shunt: Good Fz1 Shunt: Good Fz2 Shunt: Good

Calibration data is: Good Unit serial number: 02036413

Description of TI2STATUS Indications

Fatal Error: Provides an indication that the CPU is unable to run. The message indicates the

possible reason (see, “Error Messages,” on page 38 for a list of the possible errors).

Boot Loader version: The boot loader is a program that verifies that the main program is complete. The

version number is a reference for use by service personnel (see, “Error

Messages,” on page 38 for a list of the possible errors).

FPGA version: Identifies the version of the functions programmed in the field programmable

gate array. The version number is a reference for use by service personnel.

Firmware Version: Displays the version of the software installed in the TI. This software is stored in

flash memory and if needed can be upgraded in the field by an MTS service engineer.

SWIFT

Mini TI

Software Utilities

TI2STATUS - Transducer Interface Status

Zero: Indicates whether the transducer zeroing was successful or not (see, “Error

Messages,” on page 38 for a list of the possible errors).

F## Shunt: Indicates the status of shunt test for each bridge (see, “Error Messages,” on page

38 for a list of the possible errors).

Calibration data is: Indicates that the TI calibration data passed a data consistency check. The TI is

calibrated by itself, before system calibration is performed. this allows a TI to be swapped without significantly affecting system calibration. For more information see, “Error Messages,” on page 38 for a list of the possible errors).

Unit serial number: Displays the serial number of the TI box.

Software Utilities

SWIFT® Mini TI

TI2XFER - Transducer Interface Transfer

This program is used to read the current settings in the TI and save them to the computer (upload) or write the values from a calibration file on the computer to a TI (download).

Syntax ti2xfer

The following is an example of the ti2xfer command:

Example

C:\bin>ti2xfer

SWIFT Mini TI transfer (Version 1.0) Upload and download settings

0...Exit

1...Upload settings from TI box

2...Download settings to TI box Choice? 1 Filename? sample.cal

0...Exit

1...Upload settings from TI box

2...Download settings to TI box Choice? 0

File Format The file used with commands contains a header and version number, 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.

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

ParamName=ParamValue

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, a

warning will be reported.

SWIFT

Mini TI

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. Only those parameters in the file are downloaded. Parameters not in the file are unchanged.

Software Utilities

TI2XFER - Transducer Interface Transfer

CAUTION

Make important files (such as those containing calibration data) read-only after uploading.

If not protected, important data may get overwritten.

Make important files read-only. Make backups of important data.

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.

More about TI2XFER

files

The calibration files created by TI2XFER are plain text files that can be read by Microsoft Notepad or WordPad (see the example calibration file on page 45). 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.

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 TI is calibrated by itself, calibration settings for a given transducer can be used with any TI, however, some calibration methodologies require the transducer, cable and TI to be used as a calibration set (end-to-end calibration).

The serial number in the TI2XFER settings file is the serial number of the TI that the settings were first uploaded from.

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

Software Utilities

SWIFT® Mini TI

TI2SHUNT - 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 ti2shunt

Example

C:\bin>ti2shunt

SWIFT Mini TI Shunt (Version 1.0)

0...Exit

1...Read current shunt status

2...Set the TI shunt tolerance

3...Scan inputs with shunts

4...Command a shunt cal

5...Set references to last measured Enter choice: 1

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

Option 0 Use this option to exit the program.

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

the shunt status.

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

the shunt is executed after power is applied. Refer to, “Error Messages,” on page 38.

The following is typical of what is displayed when this selection is made:

Enter choice: 1 FX1 Ref: 0.854 Measured: 0.854 Status: Good

FX2 Ref: 0.855 Measured: 0.855 Status: Good FY1 Ref: 0.857 Measured: 0.857 Status: Good FY2 Ref: 0.858 Measured: 0.857 Status: Good FY3 Ref: 0.856 Measured: 0.856 Status: Good FY4 Ref: 0.857 Measured: 0.856 Status: Good FZ1 Ref: 0.856 Measured: 0.856 Status: Good FZ2 Ref: 0.856 Measured: 0.855 Status: Good

SWIFT

Mini TI

Software Utilities

TI2SHUNT - Transducer Interface Shunt

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

Enter choice: 2 The current shunt tolerance is 2% Enter new shunt tolerance in percent?

Option 3 Use this option to apply a shunt to each bridge individually, read the output of the

bridge, compare the result with the value stored in the Transducer Interface and display the difference each bridge. See the table on the next page. The shaded fields are the bridge being shunted. The actual sequence depends on the transducer wiring. Note that this option does not update the shunt measured values or error status.

Enter choice: 3

FX1 FX2 FY1 FY2 FY3 FY4 FZ1 FZ2

Unshunted: 0.00050 0.00042 0.00017 -0.00050 -0.00005 -0.00033 -0.00025 0.00000

Shunted1:

Differ1:

Unshunted: 0.00017 0.00008 -0.00050 -0.00117 0.00062 -0.00033 0.00008 0.00000

Shunted2: 0.00050 0.00042

Differ2: 0.00033 0.00033

Unshunted: 0.00050 0.00008 0.00017 -0.00050 -0.00005 -0.00000 0.00042 0.00000

Shunted3: 0.00050 0.00008 -0.00017 -0.00017 0.00062 -0.00000

Differ3: 0.00000 0.00000 -0.00033 0.00033 0.00067 0.00000

Unshunted: 0.00017 0.00008 -0.00050 -0.00084 -0.00005 -0.00000 0.00075 -0.00033

Shunted4: 0.00050 0.00008 -0.00017

Differ4: 0.00033 0.00000 0.00033

Unshunted: 0.00084 -0.00025 -0.00017 -0.00017 0.00062 -0.00033 0.00008 0.00033

Shunted5: 0.00050

Differ5: -0.00033

Unshunted: 0.00050 0.00008 0.00017 -0.00050

Shunted6: -0.00017 0.00042 0.00017 -0.00017

Differ6: -0.00067 0.00033 0.00000 0.00033

Unshunted: 0.00050 0.00042 -0.00017 -0.00084 -0.00005 -0.00033 0.00008

Shunted7: 0.00084 0.00008 0.00050 -0.00050 -0.00005 -0.00033 0.00008

Differ7: 0.00033 -0.00033 0.00067 0.00033 0.00000 0.00000 0.00000

Unshunted: 0.00017 0.00008 0.00017 -0.00084 -0.00005

Shunted8: -0.00017 0.00008 0.00017 -0.00050 0.00028

Differ8: -0.00033 0.00000 0.00000 0.00033 0.00033

0.85475 0.00008 -0.00017 -0.00050 0.00028 -0.00033 -0.00025 0.00000

0.85424 -0.00033 -0.00033 0.00000 0.00033 0.00000 0.00000 0.00000

0.85675 -0.00117 0.00028 -0.00000 0.00008 0.00000

0.85725 0.00100 -0.00033 0.00033 0.00000 0.00000

0.85620 -0.00033

0.85579 -0.00033

0.85747 -0.00005 -0.00033 0.00008 0.00000

0.85831 0.00000 -0.00033 -0.00067 0.00033

0.85557 -0.00017 -0.00050 -0.00005 -0.00033 0.00042 0.00000

0.85582 0.00000 -0.00033 -0.00067 0.00000 0.00033 -0.00033

-0.00038 -0.00000 0.00008 0.00033

0.85614 -0.00033 -0.00025 -0.00033

0.85653 -0.00033 -0.00033 -0.00067

0.00000

0.85510

-0.00000 0.00008 0.00067

0.85610 0.00008 0.00000

0.85610 0.00000 -0.00067

Software Utilities

Option 4 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 TI. A period is displayed on the screen for every change in the shunt state. This gives you a quick view of the progress.

SWIFT® Mini TI

TI2SHUNT - Transducer Interface Shunt

Option 5 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. This is normally done as part of calibration and should not be done during normal use. After this option has executed, uploads will contain the new shunt reference values.

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

SWIFT

Mini TI

Software Utilities

Error Messages

When a SWIFT utility encounters an error, the red failed indicator on the TI front panel lights. Run the TI2STATUS program to identify the cause of the error.

Following is a list of possible error messages:

• Fatal Errors

NONE Failed command port initialize Failed I2C (integrated-integrated-circuit) initialize Failed non-volatile memory initialize Failed compute module initialize Failed ADC (analog-to-digital converter) initialize Failed DAC (digital-to-analog converter) initialize Failed calibration multiplexer initialize Failed while reading I2C Failed timer initialize Failed interrupt initialize Failed encoder initialize Failed zero module initialize Failed shunt module initialize Unrecognized failure code – This error could be due to hardware

failures or software bug.

• Boot Loader – The boot loader runs when you turn on power. This line

displays the version number if boot was successful.

Error, boot loader has not run – This occurs if the CPU is not running.

Error, the boot loader has not finished – Something prevented the

CPU from completing booting the main program. Error, the boot loader found a bad Flash CRC (cyclic redundancy

check) – This error is likely due to a corrupted Flash program.

Software Utilities

Computed CRC = Flash CRC =

Error, unrecognized boot loader error code of: – Possibly corrupted

memory; communications or the version of TI2STATUS is not compatible with the firmware.

SWIFT® Mini TI

• Zero

Good – no problems detected Bad Angle Offset – The change in angle was not 90°, ±2°. Direction Change – The direction of 90° increments reversed.

• Shunt

Good – no problems were detected. Reference Bad – The shunt reference is out of range. Shunted Bad – A shunt value does not match the shunt reference. Unshunted Bad – While shunting one bridge another bridge output

unexpectedly changed.

• Calibration Data is:

Good – No problems were detected. Bad – The unit has not been calibrated or the calibration memory is

corrupted.

Error Messages

SWIFT

Mini TI

Software Utilities

Error Messages

Software Utilities

SWIFT® Mini TI

Transducer Interface Setup

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

you will be using the SWIFT sensor on the test track (typical for spinning application) or in the laboratory (typical for non-spinning or fixed application). Angular transformation is required on the test track only. If you are using the same transducer and TI for data collection on the test track and simulation testing in the laboratory, you must change the software configuration in the TI when you change testing modes.

Contents USB Driver Installation 42

Select a Zero Method 44

Calibration File Elements 45 Upload the Calibration File 47 Edit the Calibration File 48 Download the Calibration File 52

SWIFT® Mini TI

Transducer Interface Setup

USB Driver Installation

Two USB 2.0 drivers must be installed to recognize the Transducer Interface. Perform the following procedure to install these drivers on a laptop or desktop computer that does not already have these drivers installed.

Important Do not allow Windows to search for or choose the drivers for you.

Always direct Windows to the path containing the Mini TI USB drivers.

1. Copy the Mini TI USB drivers from the Utilities CD provided to your hard drive.

2. Push and hold the Power button on the Mini TI. Release the button when the Power indicator lights.

All the indicators on the Mini TI will light briefly then go out leaving only the Power indicator lit.

3. Connect the USB cable between the computer and the Mini TI. The Found New Hardware Wizard will launch. On the screen that

displays, select the No, not this time radio button (see the next figure).

Transducer Interface Setup

SWIFT® Mini TI

USB Driver Installation

4. On the next window, select the Install from a list or specific location (Advanced) radio button.

5. If you copied the driver files from the CD to your hard drive, use the browser to direct the wizard to the location where you copied the files as shown in the next figure.

6. Click Next to install the loader for the MTS SWIFT TI Interface

7. When the installation is complete, click Finish on the window that displays.

SWIFT

Mini TI

8. Another Found New Hardware Wizard will display. Repeat Steps 4 through 7 to install the MTS SWIFT TI Interface driver for

the TI Interface.

9. If prompted by Windows, restart your computer to activate the new settings.

Transducer Interface Setup

Select a Zero Method

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

Equipment required You wil l need:

• A laptop computer (at test track) or desktop PC with Window 2000 or XP

operating system.

• A USB 2.0 communication cable with type A to type B connectors.

• SWIFT Transducer Interface Utilities diskette.

• Some experience with DOS commands and text editors.

Modes There are two separate modes for using the transducer interface. The mode you

choose depends on whether you will use the transducer in a spinning (test track) application (AngleMode = 0) or non-spinning (road simulator) application (AngleMode = 1).

If you are using the same transducer with a road simulator that you used previously on the test track, or vice versa you must download the proper calibration file and re-zero the transducer.

In either mode, the zero button on the front panel of the TI is used to zero the angle and balance the bridges.

What you need to do To change the angle mode used by the TI:

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

Note A separate calibration file was created at the factory for each transducer.

In the next steps, note the serial number of the transducer identified in the calibration file and the serial number of the TI box that the file was downloaded to. This information will be used later.

2. Edit the calibration file to select appropriate angle mode: 0 = spinning, 1 = non-spinning (fixed).

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.

Transducer Interface Setup

SWIFT® Mini TI

Calibration File Elements

The following figure shows some elements of the calibration file:

Select a Zero Method

SWIFT

Mini TI

Typical Calibration File

Transducer Interface Setup

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 identified on the transducer label.

• 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.

• Y-Axis Offset—shifts the output coordinate system along the y-axis

• Output 7 signal—selects Angle of Angular Velocity for analog output

channel 7.

• VelocityFullscale—sets the 10 V fullscale value for the Angular Velocity

output.

Transducer Interface Setup

SWIFT® Mini TI

Upload the Calibration File

A unique calibration file was loaded into the TI memory by MTS before the transducer and transducer interface were shipped. Use the program TI2XFER to retrieve the calibration file.

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

Note Ensure the proper USB 2.0 drivers are installed on the laptop or PC.

Refer to, “USB Driver Installation,” on page 42, as necessary

2. Insert the SWIFT Transducer Interface Utilities CD or diskette into the laptop computer or PC.

3. Run the program TI2XFER.

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

5. Enter a file name.

6. TI2XFER will prompt you when the file has uploaded.

Upload the Calibration File

SWIFT Mini TI transfer (Version 1.0) Upload and download settings

0...Exit

1...Upload settings from TI box

2...Download settings to TI box Choice? 1

Filename? sample.cal

0...Exit

1...Upload settings from TI box

2...Download settings to TI box Choice? 0

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

SWIFT

Mini TI

Transducer Interface Setup

Edit the Calibration File

CAUTION

Edit the Calibration File

The calibration file contains offset values for all of the bridge outputs. Changing any values other than 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.

1. Open the calibration file using a text editor. Typically two calibration files are provided with each transducer: one for

spinning applications and one for non-spinning (fixed) applications. The spinning application files are usually names in the format

<transducer serial number>s.cal. The non-spinning (fixed) application files are usually names in the format

<transducer serial number>f.cal.

Transducer Interface Setup

SWIFT® Mini TI

Output Polarity Value

S20-34

Front

Fz Up

Out

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

Edit the Calibration File

2. If necessary, edit the value for Polarity (see the table below).

The polarities that match the coordinate icon on the transducer are:

Fx=0 Fy=0 Fz=0 Mx=1 My=0 Mz=1

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 = 5 Common setting to

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

OutputPolarities (left side) = 1 OutputPolarities (right side) = 0

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.

SWIFT

Mini TI

Transducer Interface Setup

Edit the Calibration File

3. If desired, set up the coordinate system offset. In the following figure, Fx, Fy, Fz is the original default coordinate system

location. F’x, F’y , F’z is the output coordinate system with a y-axis negative offset. The offset is entered in the calibration file:

// Coordinate system offset in mm. // A non-zero value will shift the location of the output // coordinate system along the transducer's y-axis. A // positive value will shift the coordinate system from // the center of the transducer body in the positive // y-axis direction by the amount specified. YAxisOffset = [user entered offset]

If the offset in this example is 100mm, the calibration file parameter would be entered as:

YAxisOffset = -100.0

Transducer Interface Setup

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

A. Verify the value for AngleMode.

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

end of the process the value in the TI internal memory and is used to perform the rotational transformation of the output signals.

SWIFT® Mini TI

Edit the Calibration File

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

mode (spinning applications). This value is summed with the encoder output count. At the end of the process the value in the TI internal memory and used 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.

C. Verify that EncoderSize=2048. D. If applicable, enter the Angular Velocity full scale.

The Angular Velocity full scale is entered in the calibration file:

// Velocity output scaling (rad/s) VelocityFullscale = 60.0

5. Perform this step for non-spinning (fixed) applications. For spinning applications, skip to Step 6.

A. Verify 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.

B. Edit the value for AngleFixed.

The AngleFixed value is used for non-spinning applications. This value addresses the sine and cosine in memory when the angle mode is set to 1 (fixed).

Use a non-zero 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

6. Save the changes and exit the editor.

SWIFT

Mini TI

7. Download the calibration file to the appropriate TI box. See, “Download the

Calibration File,” on page 52.

Transducer Interface Setup

Download the Calibration File

Use the program TI2XFER to download the modified calibration file to the TI.

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

2. Run the program TI2XFER.

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

4. Enter the name of the file you wish to download.

5. TI2XFER will prompt you when the file has successfully downloaded.

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

SWIFT Mini TI transfer (Version 1.0) Upload and download settings

0...Exit

1...Upload settings from TI box

2...Download settings to TI box Choice? 2

Filename? sample.cal

0...Exit

1...Upload settings from TI box

2...Download settings to TI box Choice? 0

Program completed

Transducer Interface Setup

SWIFT® Mini TI

Installation

Contents Transducer Interface Electronics Installation 54

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.

SWIFT Sensor Setup for Data Collection 56 Quality of the Zero Procedure Verification 60 Data Collection 61 Road Simulator 63 Zero the Transducer Interface 64

SWIFT® Mini TI

Installation

Transducer Interface Electronics Installation

The Transducer Interface (TI) electronics should be securely fastened to the vehicle. 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 on the vehicle that is convenient. However, it should be protected from impact and securely attached to the vehicle to prevent it from being dislodged during testing.

Considerations Consider the following guidelines when you fasten the TI box(es) to the vehicle:

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

and high acceleration events.

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

• 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 the data cables from the TI to the data recorder.

There is a single cable assembly, with a D-type connector for connection from the J2 Output connector on the TI and seven BNC connectors to the data recorder. The BNC connectors correspond to:

• the three forces,

• the three moments, and

• angle or angular velocity (user selectable).

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.

2. Connect the TI to the power source (such as the vehicle battery). The TI is grounded through the power connection to the battery negative

terminal. If needed, an additional ground can be attached to the TI chassis.

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.

Installation

SWIFT® Mini TI

Transducer Interface Electronics Installation

12 Vdc

Transducer Interface

S10-25

Data Recorder

12 Vdc

Transducer Interface

S10-26

Data Recorder

The data recorder should also be connected to the battery negative terminal. (See the following figures.)

Suggested Grounding for a single TI Box

SWIFT

Mini TI

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

Note If the TI box is not properly secured, it can dislodged from the vehicle.

4. Cover the J4 I/O and J5 USB connectors to protect the connectors from

5. Turn on the TI.

Suggested Grounding for a Multiple TI Boxes

contamination.

Press and hold the Power switch until the indicator lights. All other indicators will light until initialization is complete and then turn off. Only the Power indicator should remain lit.

Installation

SWIFT Sensor Setup for Data Collection

CAUTION

SWIFT Sensor Setup for Data Collection

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:

Do not touch or bump the wheel while the transducer is zeroing (after you have pressed the Zero button).

T ouching or bumping the wheel will add loads to the transducer, resulting in an erroneous zero reading.

After pressing the Zero button, avoid all contact with the wheel until the transducer zeroing at the current angle is complete. If you suspect that the zero process is incorrect, begin again.

This zero method samples all eight input bridges at four 90° intervals (that is at 0°, 90°, 180°, and 270°). 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.

The following procedure assumes:

• The transducers have been properly installed on the vehicle and the TI boxes

have been connected to the transducers and a power source. See

“Transducer Interface Electronics Installation” on page 54.

• Ensure that the connector that attaches the signal cable to the top of the

slip ring is secured 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

• The calibration file for each transducer has been edited, as required, for the

angle mode and polarity, and the calibration files have been downloaded to the TI boxes. See “Edit the Calibration File” on page 48.

Zero the TI When you zero the TI, you want the vehicle to be fairly level and the transducer

Installation

to be as close to plumb as practical.

SWIFT® Mini TI

SWIFT Sensor Setup for Data Collection

Axes Icon

1. Raise the vehicle with a lift or with jacks until each wheel is off the road surface.

The vehicle should be raised in a level manner, such that the orientation of the anti-rotate bar is the same in the lifted position as it was in the grounded position.

Note Perform the remainder of this procedure completely for one transduce r/

TI box combination at a time.

Important Performing the following step is critical after power-up.

2. Rotate the tire one full revolution so that the encoder can find the zero index mark.

Note The encoder has a re d 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.

3. Rotate the tire, as necessary, until the Fz on the axes icon (see the next figure) printed on the transducer label is pointing up.

4. If not already assembled, attach the inclinometer to the level bracket using the two 6-32 UNC fasteners provided.

Apply Locktite 222 to the threads on the fasteners. Torque each fastener to 2 N•m (18 lbf•in).

SWIFT

Mini TI

Installation

SWIFT Sensor Setup for Data Collection

Zero Button and Indicators

5. Install the inclinometer/level bracket assembly on the transducer by inserting the dowel pins in the level bracket into the pin pilot holes provided in the transducer, as shown in the next figure.

The orientation of the inclinometer/level bracket assembly is determined by the orientation of the anti-rotate bracket.

6. Adjust the tire rotation, as necessary , until the inclinometer reads 0.0°, ±0.1° (or 90.0°, ±0.1°) depending on the orientation of the inclinometer as shown in the previous figure.

7. Push the Zero button on the front of the TI box. The Zero indicators will toggle during the zero process. When the Zero

indicators turn off the process is complete for this angle.

8. Remove the level bracket/inclinometer assembly.

Installation

SWIFT® Mini TI

SWIFT Sensor Setup for Data Collection

9. Repeat Step 5 through 8 three more times. Before Step 5 of each iteration, rotate the tire 90°. Always rotate the tire in the same direction. (That is, if the first rotation was

clockwise, the succeeding rotations should also be clockwise.)

Note If the red Fail indicator lights a problem was detected during the zero

process. Try repeating the procedure. Use TI2STATUS for a more detailed explanation of the problem. If you continue to have an error, consult the chapter, “Troubleshooting,” on page 73.

SWIFT

Mini TI

Installation

Quality of the Zero Procedure Verification

Shunt Button and Indicators

Quality of the Zero Procedure Verification

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 0.2% of the rated load)?

3. What is the variance in Fz (modulation) when the tire is slowly rotated? The typical value should be <500 N.

4. Perform a shunt calibration on each transducer. Press the Shunt button on the front of the TI box (see the next figure), or use

the TI2SHUNT program. The shunt indicators will toggle until the process completes. If the red failed

indicator lights, the shunt calibration has failed. The shunt calibration will fail if the measured shunt values are >2% (the

shunt tolerance) of the reference values that were set at the factory. T ypically, the shunt values will vary a maximum of 0.020-0.030 V from the reference values.

Installation

SWIFT® Mini TI

Data Collection

CAUTION

Data Collection

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

after power is restored, the wheels should be rotated at least one full revolution so that the encoder can detect the index pulse to properly convert the rotating coordinates to stationary coordinates. The transducer outputs will not be correct until this happens.

1. Remove the vehicle from the lift or jacks.

2. When the vehicle is on the ground, check to see if the Fz reading is approximately equal to the corner weight of the vehicle.

3. Ensure that the connector that attaches the signal cable to the top of the slip ring is secured 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. Perform a final inspection of the SWIFT sensor and the electronics to ensure that everything is secure and that the TI boxes are on (see the note above).

After the zeroing procedure, the settings are stored in non-volatile memory in each TI box and will be retained when power is cycled. However, if the environment temperature changes significantly, or the anti-rotate is modified, rezeroing is recommended.

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.

5. Turn on the data recorder.

6. Start data collection.

Important Before beginning data collection, read the following cautions.

The SWIFT assembly will protrude from the side of the vehicle. Bumping the SWIFT assembly into hard surfaces such as garage doors,

ramps and railings, or objects such as rocks, stumps, and earth, will damage the anti-rotate device, cable, slip ring, slip ring bracket (spider), and transducer.

SWIFT

Mini TI

Do not allow the SWIFT assembly to bump into any hard surfaces or objects while you are driving the vehicle. Remember to allow extra space on each side of the test vehicle when driving through areas with possible hazards.

Installation

Data Collection

CAUTION

WARNING

Tall grass and brush can damage the sensor components. Driving through grass and brush that is higher than the bottom edge of the

transducer can damage the cable and tear off the slip ring.

Avoid driving in any areas with tall grass and brush.

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

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.

When driving the vehicle on public roads, you must conform to all local laws and regulations.

Do not use the SWIFT sensor if it has been exposed to load cycles that exceed the full scale calibrated ranges listed on the calibration sheets provided with each transducer.

Excessive loading or load cycles could cause a fracture of the transducer, wheel rim, hub adapter, or fasteners and can result in serious injury, death or property damage.

Always be aware of the maximum full scale loads appropriate for your transducer. If the prescribed limit for any axis of the transducer has been exceeded, contact MTS for an evaluation. If necessary, arrange for the return of the transducer with the recorded load cycles to MTS for physical inspection and analysis of the load cycle history.

Installation

SWIFT® Mini TI

Road Simulator

There are two methods of using a SWIFT on a road simulator. The traditional “non-spinning” or “fixed” mode relies on the orientation of the

SWIFT during road simulator use maintaining the same orientation relative to the anti-rotate position used during road testing. The SWIFT outputs are given in set coordinates relative to the SWIFT sensor orientation, and no angular transformation is applied to the SWIFT outputs. This is the typical method of use for larger vehicles where the angle variations of the anti-rotate bar are negligible during road testing.

The second method uses the SWIFT in a “spinning” mode. While the SWIFT itself is not spinning, the outputs from the SWIFT are passed thru the rotational transformation processing in the TI box, and the actual angle of the SWIFT relative to the encoder anti-rotate is taken into account. This method is best when there are significant angle variations of the anti-rotate bar during use, as is common on many smaller, high deflection recreational vehicles.

Depending on which mode you are using, you must load the correct calibration file into the TI boxes. Two calibration files are provided with each TI box:

• For fixed (non-spinning) mode the calibration file name is

<serialnumber>f.cal.

• For spinning mode the calibration file name is <serialnumber>s.cal.

SWIFT

Mini TI

Installation

Zero the Transducer Interface

For fixed mode For the non-spinning (fixed) zero method, use the TI2Xfer to download the fixed

calibration file (serialnumberf.ca)l to the appropriate TI box. The angle mode in the calibration file should be:

AngleMode=1

Rotate the transducer such that the orientation labeling is consistent with the reference orientation. In most cases, this means rotating the transducer so the labels are upright.

If an additional angle correction is required after installation, you will need to measure the angle from zero, and then enter the new value for the AngleFixed in the TI calibration file (see earlier instructions, “Edit the Calibration File,” on page 48).

Zeroing the transducer in fixed mode can be performed before or after connecting the adapter plate to the spindle housing.

• Perform zero before

you want to zero the transducer without the effects of the vehicle load on the transducer.

With the transducer oriented as described above press Zero on the TI Box.Repeat for each transducer.

• Perform zero after

want to apply the vehicle load to the transducer before you zero the transducer.

With installation complete and the vehicle load on the transducers, press the Zero button on each TI Box.

connecting the adapter plate to the spindle housing if

connecting the adapter plate to the spindle housing if you

For spinning mode For the spinning zero method, use the TI2Xfer to download the spinning

calibration file (serialnumbers.cal) to the appropriate TI box. The angle mode in the calibration file should be:

AngleMode=0

1. Rotate the adapter plate with the transducer attached one full revolution so that the encoder passes the zero index mark.

Installation

This must be done with the TI powered on and the transducer cable connected.

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

bracket and another 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.

SWIFT® Mini TI

Zero the Transducer Interface

Axes Icon

2. Rotate the adapter plate, as necessary, until the Fz on the axes icon (see the next figure) printed on the transducer label is pointing up.

3. If not already assembled, attach the inclinometer to the level bracket using the two 6-32 UNC fasteners provided.

Apply Locktite 222 to the threads on the fasteners. Torque each fastener to 2 N•m (18 lbf•in).

4. Install the inclinometer/level bracket assembly on the transducer by inserting the dowel pins in the level bracket into the pin pilot holes provided in the transducer, as shown in the next figure.

The orientation of the inclinometer/level bracket assembly is determined by the orientation of the anti-rotate bracket.

Digital Inclinometer

–in this position

should read 0°, ±0.1°

Adapter Plate

Level Bracket

Mounting Holes (4)

Setup for Vertical Anti-rotate

Bracket Configuration

SWIFT

Mini TI

Installation

Zero the Transducer Interface

Setup for Horizontal Anti-rotate

Bracket Configuration

Axes

Icon

Digital Inclinometer

–in this position

should read 90°, ±0.1°

Level Bracket

Adapter Plate

Zero Button and Indicators

5. Adjust the adapter plate, as necessary, until the inclinometer reads 0.0°, ±0.1° (or 90.0°, ±0.1° depending on the orientation of the inclinometer) as shown in the figure above.

6. Push the Zero button on the front of the TI box. The Zero indicators will toggle during the zero process. When the Zero

indicators turn off the process is complete for this angle.

7. Remove the level bracket/inclinometer assembly.

8. Repeat Step 5 through 8 three more times. Before Step 5 of each iteration, rotate the adapter plate 90°. Always rotate the adapter in the same direction. (That is, if the first rotation

was clockwise, the succeeding rotations should also be clockwise.)

Note If the red Fail indicator lights a problem was detected during the zero

process. Try repeating the procedure. Use TI2STATUS for a more detailed explanation of the problem. If you continue to have an error, consult the chapter “Troubleshooting” on page 73.

Installation

SWIFT® Mini TI

Alternate zero procedures

Firmware changes were made to the Mini TI to make it compatible with older models. These firmware changes provide two additional zeroing procedures. For the spinning zero method, use the TI2Xfer to download the spinning calibration file (serialnumbers.cal) to the appropriate TI box. The angle mode in the calibration file should be:

AngleMode=0

Now one physically has to specify the zero algorithm. The above two procedures are the most common and still recommended but the following combinations also make sense and could be used:

Zero the Transducer Interface

AngleMode=0 (spinning) defaulted to ZeroAlgorithm=1 (angle with level, bridges with 1 rotation)

AngleMode=0 (spinning) defaulted to ZeroAlgorithm=3 (angle and bridges with 1 rotation)

Zero the TI – one revolution averaging without inclinometer

(unloaded)

ZeroAlgorithm=3.

Recommended for spinning applications… (Angle Mode = 0) (The TI will collect one revolution of raw bridge data, average the data, and

remove the DC offset by setting the zero offsets to the average value. The angle offset will be calculated using a sine curve fit to the raw bridge data)

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. Raise the vehicle with a lift or with jacks until each wheel is off the road surface.

The vehicle should be raised in a level manner, such that the orientation of the anti-rotate bar is the same in the lifted position as it was in the grounded position

Note Perform the remainder of this procedure completely for one transduce r/

TI box combination at a time.

2. Rotate the tire one full revolution so that the encoder can find the zero index mark.

Note The encoder has a re d dot on the mounting flange connected to the slip

SWIFT

Mini TI

3. Push the Zero button on the front of the TI box. When the lower Zero indicator turns on, proceed to the next step.

Installation

Zero the Transducer Interface

4. Rotate the tire in either direction until the lower Zero indicator turns off and

the upper indicator turns on (approximately 1.25 revolutions). The bridge zeros will be computed using the average value of the bridges over one full revolution. The angle offset will be calculated using a sine curve fit to the raw bridge data. Once the computation is complete, both Zero indicators will turn off.

Note If the red Fail ind icator lights a problem was detected during the zero

process. Try repeating the procedure. Use TI2STATUS for a more detailed explanation of the problem. If you continue to have an error, consult the chapter “Troubleshooting” on page 73.

Zero the TI – one

revolution averaging

with inclinometer

(unloaded)

ZeroAlgorithm=1.

Recommended for spinning applications… (Angle Mode = 0) (The TI will read the angle when the zero button is pressed and will use this as

the angle offset. It will then collect one revolution of raw bridge data, average the data, and remove the DC offset by setting the zero offsets to the average value)

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. Raise the vehicle with a lift or with jacks until each wheel is off the road surface.

The vehicle should be raised in a level manner, such that the orientation of the anti-rotate bar is the same in the lifted position as it was in the grounded position

Note Perform the remainder of this procedure completely for one transduce r/

TI box combination at a time.

2. Rotate the tire one full revolution so that the encoder can find the zero index mark.

Note The encoder has a re d dot on the mounting flange connected to the

slipring 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.

Installation

3. Rotate the tire, as necessary, until the Fz on the axes icon (see the next figure) printed on the transducer label is pointing up.

4. If not already assembled, attach the inclinometer to the level bracket using the two 6-32 UNC fasteners provided. Apply Locktite 222 to the threads on the fasteners. Torque each fastener to 2 N•m (18 lbf•in).

5. Install the inclinometer/level bracket assembly on the transducer by inserting the dowel pins in the level bracket into the pin pilot holes provided in the transducer, as shown in the next figure. The orientation of the inclinometer/level bracket assembly is determined by the orientation of the anti-rotate bracket.

6. Adjust the tire rotation, as necessary , until the inclinometer reads 0.0°, ±0.1° (or 90.0°, ±0.1°) depending on the orientation of the inclinometer as shown in the previous figure.

SWIFT® Mini TI

Zero the Transducer Interface

7. Push the Zero button on the front of the TI box. The upper Zero indicator

will turn on temporarily while the encoder angle is recorded. When the lower Zero indicator turns on, proceed to the next step.

8. Rotate the tire in either direction until the lower Zero indicator turns off and

the upper indicator turns on (approximately 1.25 revolut ions). The bri dge zeros will be computed using the average value of the bridges over one full revolution. Once the computation is complete, both Zero indicators will turn off.

Note If the red Fail ind icator lights a problem was detected during the zero

process. Try repeating the procedure. Use TI2STATUS for a more detailed explanation of the problem. If you continue to have an error, consult the chapter “Troubleshooting” on page 73.

SWIFT

Mini TI

Installation

Zero the Transducer Interface

Installation

SWIFT® Mini TI

Maintenance

Transducer Interface

Scheduled maintenance is a set of routine procedures that allow you to extend the operating life of the transducer interface electronics.

The information provided in this chapter is a recommendation only. The actual time intervals will depend on the operating conditions at your facility.

The electronics for your transducer have no internal parts that can be serviced by the user. The case is sealed against moisture. Breaking the seal by opening the case can void any warranty.

Before making any cable connections to the TI box, inspect the area of the connector for accumulated dirt.

If necessary, clean the connector areas with low pressure air or an electrical connector cleaner.

SWIFT® Mini TI

Maintenance

SWIFT® Mini TI

Troubleshooting

CAUTION

This chapter covers basic set-up related troubleshooting tips. Please read this section to investigate problems that you observe. In many cases, these problems will be setup related and can be corrected as described in this section.

Important In the event that these troubleshooting tips indicate that there is a

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

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

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

component failure, or the correction tips do not correct the problem, contact MTS.

SWIFT® Mini TI

Troubleshooting

Troubleshooting Guide (part 1 of 11)

Symptom Possible Causes Solution

Transducer Interface (TI) does not power up (green power indicator is not lit).

If any of the following conditions exist, the Power indicator next to the Power button will not turn on (green) when you press the button.

The TI power supply cable is not connected.

Check that the cable is securely connected to the TI box. At the back of the TI box, the J1 Power must be connected to a power supply or battery.

The power supply is not providing power.

If a battery is used, check that the battery is charged. See Specifications beginning on page

21 for the minimum input voltage. If an external

power supply is used, check that it is plugged into an AC supply, and that power is turned on. The fan on the top of the power supply should be on at all times when the external power supply is ON.

The power supply wiring is reversed.

If using a car battery, check that the wiring is correct. If the wiring has been reversed and the power switch turned on, it is likely the fuse has opened.

The fuse has opened. The TI box is provided with a self-resetting

thermal fuse. If input power exceeds the fuse limits, or polarity is reversed, the fuse will open. If the fuse opens, the TI box cannot be used until the fuse cools enough to reset.

FAIL indicator.

Zero Procedure: The Zero indicators stay on too long, or they continue to blink slowly, even af ter the wheel has rotated twice.

An internal failure has occurred in the TI electronics.

The angular output signal is not reaching the TI. If the encoder signal is not reaching the TI, it may eventually time out and red fail indicator will light.

The red fail indicator will stay lit if there is no encoder signal. If the encoder is disconnected after data collection has started, the data collection will time out and blink slowly.

Boot Error: Turn the TI pow e r off and on to reboot.

Internal Error: See “Hardware Overview”, for failure codes relating to FAIL indicator.

T o get additional information when the fail LED is on, run TI2STATUS.

Check that all cables are attached and undamaged. In particular, check the main signal cable from the transducer to the TI.

Check that the encoder output is present. The angle output signal from the TI should be a 0–5 V sawtooth output while the transducer is spinning at a constant velocity.

If this signal is not present, check that the slip ring/encoder assembly has not been damaged. If you suspect encoder damage, swap the slip ring assembly with a known functioning unit to verify it. If the slip ring/encoder assembly is damaged, call MTS or replace it with a spare slip ring assembly.

Troubleshooting

SWIFT® Mini TI

Troubleshooting Guide (part 2 of 11)

Symptom Possible Causes Solution

Some or all transducer output signals read 0 volts at the TI output even when a load is present.

The TI is not turned on. Check that TI is turned on and the green power

indicator is lit.

The transducer signal cable is not connected.

Check that the cable is connected between the TI box and the slip ring (or connector housing for a road simulator).

Output cables are not connected.

Cables or connectors are damaged.

Check that the output connectors are securely fastened to the data acquisition device.

Check all cables and connectors, particularly the power and transducer cable. Cables must be free of nicks or cuts, and all connector pins shown on the cable drawings must be present and not bent.

Data acquisition configuration, cabling, or input ports are incorrect or damaged.

Verify that the data acquisition is configured correctly. While the TI is turned on and the cable from the transducer to the TI is connected, use a handheld DVM to verify output on individual channels while they are being loaded.

Grounding problem. Check that there is a good signal-to-ground

connection between the TI power cable and the negative terminal on the battery

SWIFT® Mini TI

Troubleshooting

Troubleshooting Guide (part 3 of 11)

Symptom Possible Causes Solution

Zero Offset: One or more Signal Outputs appear to have an offset after the TI electronics have been zeroed.

The transducer was zeroed with load applied (or a

Rezero the TI, being careful not to touch or load

the transducer during the zero procedure. different load than the intended tare weight for non-spinning applications only).

Considerable temperature changes have occurred.

The transducer is temperature-compensated to

reduce temperature-induced errors, but any

significant changes in temperature will induce

zero shifts. For best results, zeroing should

occur at the conditions closest to those of the

test conditions. Noise in the system. Noise in the power supply or high magnetic

fields can cause errors in the zeroes. For more

information, see grounding suggestions in

“Transducer Interface Electronics Installation”

on page 54. Zero button was pressed

with cables not connected, or during a loaded test

If the Zero button is pressed with the cables not

connected, the TI Electronics will set the new

zero values according to this zero voltage

signal. If the Zero button is accidentally pressed

during a test, the TI electronics will zero the

bridges at whatever load they are reading at the

time the Zero button was pressed, resulting in

an erroneous bridge zero value. The data acquisition

configuration or input ports show a zero offset.

The reference angle of the transducer is set incorrectly in non-spinning (fixed) mode.

After zeroing, while the TI is turned on and all

cables from the SWIFT transducer to TI are

connected, use a handheld DVM to verify the

output of individual channels while they are

being loaded. With no load applied, the outputs

should be 0 V. If the data acquisition is showing

an offset while the TI reads 0 V (as measured by

the handheld DVM), the data acquisition is set

up incorrectly, or is inducing the offset.

The AngleFixed value in the TI calibration file

is initially set to zero, indicating that the

coordinate outputs shown on the transducer

label are correct when the label is upright. If the

label is not upright, or if the AngleFixed value

in the calibration file is not set correctly, the

angular transformation may be causing the

error.

For example, if the transducer should be sensing

only a vertical load with the vehicle at rest, but

the angle is set incorrectly , it may give an output

of longitudinal load and vertical load based on

this erroneous axis orientation set by the

AngleFixed value. To correct, verify that the

AngleFixed value matches the actual

orientation of the transducer.

Troubleshooting

SWIFT® Mini TI

Troubleshooting Guide (part 4 of 11)

CAUTION

Symptom Possible Causes Solution

The AngleOffset value is incorrect in the calibration file.

Excessive noise during the zero procedure caused an incorrect bridge zero, or the angle computation to be calculated incorrectly.

If an incorrect AngleOffset value is set in the TI calibration file, an axis which should have no load may show some load from another vehicle coordinate axis based on the incorrect reference orientation. Verify that the correct AngleOffset is set for your specific application (refer to,

“Edit the Calibration File,” on page 48).

Electrical Noise: The transducer has power conditioning, shielded cables and on-board amplification to reduce electrical noise. However, if the TI or transducer are very near a powerful noise source, some noise can be picked up with the signal.

Check that the TI electronics are grounded properly through the power cable to the power source. If possible, perform the zeroing and shunt calibration procedure away from the noise source.

Physical Noise: If the transducer is part of an assembly that is connected to active hydraulics or other assemblies that may experience physical vibrations, these vibrations may be picked up as inertial forces read by the transducer. Check that the transducer is not experiencing dynamic loading or vibrations during the zero process or shunt calibration.

Output levels are much higher or lower than expected

Gains in the TI calibration file have been overwritten or modified.

Use the TI2XFER program to upload the current TI calibration file (refer to, “Upload the

Calibration File,” on page 47). Check that the

gain settings match the original calibration file sent with the transducer. If they are different, download the original file to the TI, and make any mode changes needed for your specific application.

Do not make changes to the original calibration file on the disk.

Changing the original file means you will lose the original calibration data for your transducer.

Make a copy of the original file and make any changes to the copy.

SWIFT® Mini TI

Troubleshooting

Troubleshooting Guide (part 5 of 11)

Symptom Possible Causes Solution

The data acquisition scales are set incorrectly .

The transducer was zeroed with load applied (or a different load than the intended tare weight for non-spinning applications only).

A zero offset is present in the data.

Check that the data acquisition scales are set

correctly. The full scale calibration range is

shown on the Calibration Report, with 10 V =

Full Scale (unless you requested custom

calibration output before calibration at MTS).

With the TI turned on and all cables from the

transducer to TI connected, use a handheld

DVM to check the output on individual

channels while they are being loaded to make

sure that the output at the TI box and data

acquisition correlate. (Use the BNC connectors

located at the back panel of the TI.)

Rezero the TI, being careful not to touch or load

the transducer during the zeroing procedure.

See Zero Offset on the previous pages of this

Troubleshooting Guide.

Troubleshooting

SWIFT® Mini TI

Troubleshooting Guide (part 6 of 11)

Symptom Possible Causes Solution

Failed indicator lights after Shunt Calibration

The signal cable is not connected to the transducer or it is damaged or the transducer is damaged.

Excessive noise on the signal caused the shunt tolerance to be exceeded.

Perform TI2STATUS. Check that the proper calibration file was

downloaded (the serial number in the report matches the transducer serial number.

Check the error messages in the report. During a shunt calibration, the shunt cables

provide the shunt across the individual bridges, but the outputs that are verified in the TI come from the output signal cable. Check that the output signal cable is not damaged and is securely fastened to both the TI and the transducer.

Electrical Noise: The transducer has power conditioning, shielded cables, and on-board amplification to reduce electrical noise. However, if the TI or transducer are very near a powerful noise source, some noise can be picked up with the signal.

Check that the TI electronics are grounded properly through the power cable to the power source. If possible, perform the zeroing and shunt calibration procedure away from the noise source.

The slip ring or road simulator connector housing assembly is not transmitting a signal.

A temporary fix is to increase the shunt verification tolerance by changing the setting in the TI. Note that any temporary fix by increasing the tolerance may allow a shunt calibration to pass, when it may be indicative of a problem that should not be ignored.

The shunt procedure requires the output through the slip ring or connector housing. Make sure that the slip ring/connector housing connection is secure and that no connectors appear to be damaged. If possible, swap it out with another slip ring or connector housing to verify that the slip ring or connector housing component has not failed or been damaged.

SWIFT® Mini TI

Troubleshooting

Troubleshooting Guide (part 7 of 11)

Symptom Possible Causes Solution

The shunt reference values were changed.

Use the TI2XFER program to upload the

current calibration file. Check the file to verify

that the variables ShuntDeltaRef are the same

as shown on the original calibration file

provided by MTS. The eight ShuntDeltaMeas

values should read approximately 0.85 V. The shunt tolerance is not

set correctly .

Use the TI2XFER program to upload the

current calibration file. The ShuntTolerance

value should be set at 2, indicating an allowable

shunt variation of 2%. If this value is change d to

zero or a very small number, the difference

between the reference and the current shunt

measurement may fall outside of this tolerance

and be read as a shunt failure. Transducer cable problems. If the ShuntDeltaMeas values are not the same

as (or within tolerance of the ShuntDeltaRef

values), note which shunt values are not the

same.

If all eight are not correct, check the shunt

cables, signal cable, and power supply.

If four of the signals are not correct, verify that

both shunt cables are plugged in and are not

damaged. (Each shunt cable shunts four

bridges). If connections appear correct, swap

the transducer cable and check whether the bad

shunt values follow the cable. This indicates a

damaged or faulty cable. Check that the cable is

not damaged, and that connector pins are not

missing or damaged.

Troubleshooting

Use the same swapping technique if one or

more signals is not correct. In this case swap the

slip ring bracket and note which bridge has the

different value. If the faulty shunt value stays

the same with the slip ring bracket, look at the

connectors for damage or objects plugging the

connector and contact MTS.

SWIFT® Mini TI

Troubleshooting Guide (part 8 of 11)

Symptom Possible Causes Solution

Errors reported when TI2STATUS is run.

Shunt errors that TI2STATUS could report.

Zero errors that TI2STATUS could report.

• Reference Bad – a downloaded shunt

reference is zero. This is a calibration settings problem.

• Shunted Bad – A bridge being shunted

deviated from the shunt reference by more than the limit. This could be caused by a sensor failure, transducer cable failure, TI failure, bad shunt reference setting or bad shunt tolerance setting.

• Unshunted Bad – A bridge not being

shunted deviated by more than the limit. This is likely caused by a short in the transducer or transducer cable.

• Bad Angle Offset – the transducer should

have been rotated +/-90 degrees but the measured angle was different by more than the limit (currently 2 degrees). This could be caused by not passing the index mark before starting the zero, not rotating by the correct angle, a bad angle sensor or a bad transducer cable.

• Direction Change – the direction the

transducer was rotated changed during the zero process. The transducer needs to be rotated in 90 degree increments the same direction in each step of the zero process so data can be collected for each one of the sensor beams (0, 90, 180 and 270 degrees).

SWIFT® Mini TI

• Missing Data Points – a zero method that

collects data while the transducer is rotated found too many consecutive missing data points. This is likely caused by rotating the transducer too fast.

• Invalid Algorithm – the zero algorithm

specified is not recognized. This is likely the calibration setting problem that could be affected by software and firmware version.

Troubleshooting

Troubleshooting Guide (part 9 of 11)

Symptom Possible Causes Solution

Shunt Calibration as Recorded by External Data Acquisition is incorrect or inconsistent. (The internal shunt check in the TI electronics verifies each of the eight individual bridges, but it is the six bridge 10 V output that you can record if desired.)

The output signal polarity is incorrect

Reference Angle is incorrect

The gains have been changed in the calibration file.

As the bridges are shunted, the eight raw bridge outputs pass through the TI box and have the calibration gains applied to them. If the calibration file has been changed or modified, the six bridge 10 V outputs will reflect this. Use the TI2XFER utility to verify that the calibration settings portion of the calibration file matches the original, and download the original to TI if needed.

Data acquisition configuration, settings,

Investigate the data acquisition system to verify

that it is configured properly. offset, or scaling is incorrect, changed, or inconsistent

The Polarity setting for one or more axes is incorrect

Check the polarity for each axis in the

calibration file and compare it with the desired

configuration as described in the, “Edit the

Calibration File,” on page 48

Reference Angle is 180° off. If the reference angle is 180° off, the output

polarity of some channels may appear to be

reversed. The reference angle can be verified as

described later in this table. Zero was done with anti-

rotate device not attached, or attached with orientation different than test set-up.

Make sure that the anti-rotate and slip ring

assembly are securely fastened during the

spinning zero procedure. If the anti-rotate or slip

ring is removed or rotated from the transducer,

rezeroing the transducer angle is required.

Spinning Application: Vehicle Coordinate System Outputs have unusual or incorrect waveform shapes to them. (Angular output may need to also be recorded to troubleshoot based on per-revolution outputs)

Troubleshooting

A one-time-per-revolution of tire signal appears while the vehicle is driving straight on a flat surface. The mean level on FX and FZ is equal to zero, and the amplitude is fairly consistent during straight driving on a flat surface. The amplitudes on FX and FZ are about the same and equal to the vehicle weight.

Angle Mode: Check that the AngleMode value

is set to zero in the TI calibration file as

accessed by the TI2XFER utility.

AngleMode=0 sets the TI to use the encoder to

give angular transformation to the spinning

signal, to provide non-spinning vehicle

coordinate system output.

Angle Input: Verify that the encoder output is

present. The Angle output from the TI box

should be a 0 to 5 V sawtooth output. If this

signal is not present, check that the encoder and

slip ring assembly has not been damaged. To

verify if encoder damage is suspected, swap the

slip ring assembly with a known functioning

unit to verify. If the slip ring/encoder assembly

is damaged call MTS or replace it with spare

slip ring assembly if available.

SWIFT® Mini TI

Troub leshooting Guide (part 10 of 11)

Symptom Possible Causes Solution

A one-time-per-revolution of tire signal appears while the vehicle is driving straight on a flat surface. Mean level of the FZ output is roughly equal to the weight of the vehicle on that corner.

A two-time-per-revolution of tire signal is showing up when the vehicle is driving straight on a flat surface.

Temperature Effects: The SWIFT transducer is temperature compensated to reduce temperature induced errors, but any significant changes in temperature will induce zero shifts. In the spinning application, these bridge zero shifts will result in a one-time-per rev modulation error. For best results, zeroing should occur at the conditions closest to those of the test conditions.

Incorrect Bridge Zero: An incorrect bridge zero, in the spinning application, will result in a one-time-per-rev modulation error. See “Zero Offset” earlier in this Troubleshooting Guide.

Gain settings: Verify that the TI electronics calibration file gain settings have not been modified. Using the T2IXFER program, upload the current TI settings and compare them to the original gain setting on the disk provided.

Bridge Failure: If a single bridge is failing due to overstress, overload induced crack, and so on, the results could appear as this type of output. To verify that this is the cause, use the TI2XFER program to upload the current TI settings after a zeroing procedure. Load the transducer for several cycles, without inducing heat (drive vehicle for a few cycles but do not use excessive brake heating). Rezero the TI electronics. Use TI2XFER to upload the new zero values. Compare them to the previously recorded zero values. These values should not change by more than 0.01 to 0.03 for two zeroes done at the same conditions, on the same transducer. If the changes are much larger, remove the transducer from vehicle and contact MTS.

SWIFT® Mini TI

Troubleshooting

Troubleshooting Guide (part 11 of 11)

Symptom Possible Causes Solution

Spinning Application: Vehicle Coordinate System Outputs have unusual or incorrect waveform shapes to them. (Continued)

Angle/Angular Velocity Output

A four-time-per-revolution of tire signal is showing up when the vehicle is driving straight on a flat surface.

There is no angle or angular velocity output while the transducer and slip ring are spinning.

Wheel force transducers often have a

modulation error with a cyclic frequency equal

to the number of beams on the transducer. The

SWIFT transducer has four beams, and will

inherently have some level of four times per

revolution modulation. This level will vary from

±0.5% to as high as ±5% of the equivalent radial

load.

For example, a 4000 N mean level vertical Fz

load (and negligible Fx loading) will result in a

±20 N to ±200 N error on the vertical Fz and Fx

channels.

The magnitude of this modulation error is based

on the geometries and stiffnesses of the

components in the assembly.

A transducer on a steel rim will have lower

modulation than the same transducer on a very

lightweight stainless steel rim. The trade-offs

between lower added mass, load capacity

requirements, and desired modulation should all

be considered in choosing components for the

wheel force transducer assembly.

Check that all power and signal cables are

connected, and that the antirotate device is

securely attached. The angle output should be

0 to 5 V sawtooth out put per revolution of the

tire. The angular velocity signal should be

proportional to the rotational speed.

System coordinate offset is not working properly

Troubleshooting

The output Fullscale** values have been modified in the calibration file.

If the output is set to Angular Velocity, check

the VelocityFullscale value in the calibration

file.

Check that the encoder output is present. The

angle output signal from the TI should be a 0 to

5 volt sawtooth output while the transducer is

spinning at a constant velocity.

If this signal is not present, check that the slip

ring/encoder assembly has not been damaged. If

you suspect encoder damage, swap the slip ring

assembly with a known functioning unit to

verify it. If the slip ring/encoder assembly is

damaged, call MTS or replace it with a spare

slip ring assembly.

Make sure the fullscale values in the calibration

file are correct and represent units of kN and

kN·m.

SWIFT® Mini TI

MTS Systems Corporation

14000 Technology Drive Eden Prairie, Minnesota 55344-2290 USA Toll Free Phone: 800-328-2255

(within the U.S. or Canada)

Phone: 952-937-4000

(outside the U.S. or Canada) Fax: 952-937-4515 E-mail: info@mts.com Internet: www.mts.com

ISO 9001 Certified QMS

MTS WIFT Mini Transducer Interface 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

Overview

Spinning Applications (Track or Road)

Non-Spinning Applications (Laboratory)

Design Features

Coordinate System

Specifications

Calibration

Transducer Interface

TI Front Panel

TI Rear Panel

Software Utilities

Introduction

TI2STATUS - Transducer Interface Status

Description of TI2STATUS Indications

TI2XFER - Transducer Interface Transfer

TI2SHUNT - Transducer Interface Shunt

Error Messages

Transducer Interface Setup

USB Driver Installation

Select a Zero Method

Calibration File Elements

Upload the Calibration File

Edit the Calibration File

Download the Calibration File

Installation

Transducer Interface Electronics Installation

SWIFT Sensor Setup for Data Collection

Quality of the Zero Procedure Verification

Data Collection

Road Simulator

Zero the Transducer Interface

Alternate zero procedures

Maintenance

Transducer Interface

Troubleshooting