Trademark informationMTS, SWIFT, TestStar, and TestWare are registered trademarks of MTS Systems
Corporation within the United States. These trademarks may be protected in
other countries.
Microsoft, Windows, Windows for Workgroups, Windows 95, and Windows NT
are registered trademarks of Microsoft Corporation. Apple and Macintosh are
registered trademarks of Apple Computer, Inc. UNIX is a registered trademark of
The Open Group. All other trademarks or service marks are property of their
respective owners.
Publication information
MANUAL PART NUMBERPUBLICATION DATE
151956-00 BFebruary 1999
100-026-689 AJune 2000
100-026-689 BJuly 2000
100-026-689 CMay 2005
100-026-689 DOctober 2005
100-026-689 EJanuary 2006
100-026-689 FNovember 2008
2
Contents
Technical Support 7
How to Get Technical Support 7
Before You Contact MTS 7
If You Contact MTS by Phone 9
Problem Submittal Form in MTS Manuals 10
Preface 11
Before You Begin 11
Conventions 12
Documentation Conventions 12
Hardware Overview 15
Spinning Applications (Test Track) 16
Non-spinning Applications (Simulation Lab) 17
Construction 18
Design Features 22
Coordinate System 23
Specifications 25
Calibration 29
Transducer Interface 31
TI Front Panel 34
TI Rear Panel 41
TI Jumpers 42
Interfacing with RPC 43
Software Utilities 45
Introduction 46
TISTATUS - Transducer Interface Status 47
TIXFER - Transducer Interface Transfer 48
TISHUNT - Transducer Interface Shunt 50
Setting Up Shunt Calibration Reference Values 54
TISETZERO – Transducer Interface Set Zero Method 55
Error Messages 56
SWIFT 30 SensorsContents
3
Shunt Error Status 57
Setting up the Transducer Interface 59
Select a Zero Method 60
Calibration File Elements 61
Zero Algorithms 62
Upload the Calibration File 64
Edit the Calibration File 66
Download the Calibration File 70
Installing the Transducer 73
Test Track Vehicle 74
Attaching SWIFT Components to the Vehicle 78
Attaching SWIFT and Wheel Assembly to the Vehicle 81
Installing the Transducer Interface Electronics 83
Setting up the SWIFT Sensor for Data Collection 85
Verifying the Quality of the Zero Procedure 95
Collecting Data 97
Road Simulator 99
Attaching SWIFT Components to the Fixturing 101
Zeroing the Transducer Interface 104
Communication Configurations 105
Cable Configurations 106
SWIFT TI to PC Host (9-pin) 106
SWIFT TI to PC Host (25-pin) 106
SWIFT TI to SWIFT TI 106
Termination Jumper 107
Analyzing SWIFT Data 109
The Data 110
Fx Data (Longitudinal Force) 111
Fz Data (Vertical Force) 113
Mx Data (Overturning Moment) 114
My Data (Brake Moment) 117
Acceleration and Braking Events Example 119
Slalom Curve Driving Example 121
Contents
4
SWIFT 30 Sensors
Maintenance 123
Transducer 124
Transducer Interface 125
Cables 126
Troubleshooting 127
Assembly Drawings 141
Cable Drawings 142
SWIFT 30 Mechanical Parts 157
Common Parts 165
SWIFT 30 SensorsContents
5
6
Contents
SWIFT 30 Sensors
Technical Support
How to Get Technical Support
Start with your
manuals
Technical support
methods
MTS web site
www.mts.com
E-mailtechsupport@mts.com
TelephoneMTS Call Center 800-328-2255
Fax952-937-4515
Technical support
outside the U.S.
The manuals supplied by MTS provide most of the information you need to use
and maintain your equipment. If your equipment includes MTS software, look
for online help and README files that contain additional product information.
If you cannot find answers to your technical questions from these sources, you
can use the internet, e-mail, telephone, or fax to contact MTS for assistance.
MTS provides a full range of support services after your system is installed. If
you have any questions about a system or product, contact MTS in one of the
following ways.
The MTS web site gives you access to our technical support staff by means of a
Technical Support link:
www.mts.com > Contact MTS > Service & Technical Support
Weekdays 7:00 A.M. to 5:00 P.M., Central Time
Please include “Technical Support” in the subject line.
For technical support outside the United States, contact your local sales and
service office. For a list of worldwide sales and service locations and contact
information, use the Global MTS link at the MTS web site:
www.mts.com > Global MTS > (choose your region in the right-hand
column) > (choose the location closest to you)
Before You Contact MTS
MTS can help you more efficiently if you have the following information
available when you contact us for support.
Know your site
number and system
number
SWIFT 30 SensorsTechnical Support
The site number contains your company number and identifies your equipment
type (material testing, simulation, and so forth). The number is usually written on
a label on your MTS equipment before the system leaves MTS. If you do not
have or do not know your MTS site number, contact your MTS sales engineer.
Example site number: 571167
When you have more than one MTS system, the system job number identifies
which system you are calling about. You can find your job number in the papers
sent to you when you ordered your system.
Example system number: US1.42460
7
Know information from
prior technical
If you have contacted MTS about this problem before, we can recall your file.
You will need to tell us the:
assistance
•MTS notification number
•Name of the person who helped you
Identify the problemDescribe the problem you are experiencing and know the answers to the
following questions:
•How long and how often has the problem been occurring?
•Can you reproduce the problem?
•Were any hardware or software changes made to the system before the
problem started?
•What are the model numbers of the suspect equipment?
•What model controller are you using (if applicable)?
•What test configuration are you using?
Know relevant
computer information
Know relevant
software information
If you are experiencing a computer problem, have the following information
available:
•Manufacturer’s name and model number
•Operating software type and service patch information
•Amount of system memory
•Amount of free space on the hard drive in which the application resides
•Current status of hard-drive fragmentation
•Connection status to a corporate network
For software application problems, have the following information available:
•The software application’s name, version number, build number, and if
available, software patch number. This information is displayed briefly
when you launch the application, and can typically be found in the “About”
selection in the “Help” menu.
•It is also helpful if the names of other non-MTS applications that are
running on your computer, such as anti-virus software, screen savers,
keyboard enhancers, print spoolers, and so forth are known and available.
Technical Support
8
SWIFT 30 Sensors
If You Contact MTS by Phone
Your call will be registered by a Call Center agent if you are calling within the
United States or Canada. Before connecting you with a technical support
specialist, the agent will ask you for your site number, name, company, company
address, and the phone number where you can normally be reached.
If you are calling about an issue that has already been assigned a notification
number, please provide that number. You will be assigned a unique notification
number about any new issue.
Identify system typeTo assist the Call Center agent with connecting you to the most qualified
technical support specialist available, identify your system as one of the
following types:
•Electromechanical materials test system
•Hydromechanical materials test system
•Vehicle test system
•Vehicle component test system
•Aero test system
Be prepared to
troubleshoot
Write down relevant
information
After you callMTS logs and tracks all calls to ensure that you receive assistance and that action
Prepare yourself for troubleshooting while on the phone:
•Call from a telephone when you are close to the system so that you can try
implementing suggestions made over the phone.
•Have the original operating and application software media available.
•If you are not familiar with all aspects of the equipment operation, have an
experienced user nearby to assist you.
Prepare yourself in case we need to call you back:
•Remember to ask for the notification number.
•Record the name of the person who helped you.
•Write down any specific instructions to be followed, such as data recording
or performance monitoring.
is taken regarding your problem or request. If you have questions about the status
of your problem or have additional information to report, please contact MTS
again and provide your original notification number.
SWIFT 30 SensorsTechnical Support
9
Problem Submittal Form in MTS Manuals
Use the Problem Submittal Form to communicate problems you are experiencing
with your MTS software, hardware, manuals, or service which have not been
resolved to your satisfaction through the technical support process. This form
includes check boxes that allow you to indicate the urgency of your problem and
your expectation of an acceptable response time. We guarantee a timely
response—your feedback is important to us.
The Problem Submittal Form can be accessed:
•In the back of many MTS manuals (postage paid form to be mailed to MTS)
•www.mts.com > Contact Us > Problem Submittal Form (electronic form to
be e-mailed to MTS)
Technical Support
10
SWIFT 30 Sensors
Preface
Before You Begin
Safety first!Before you attempt to use your MTS product or system, read and understand the
Safety manual and any other safety information provided with your system.
Improper installation, operation, or maintenance of MTS equipment in your test
facility can result in hazardous conditions that can cause severe personal injury or
death and damage to your equipment and specimen. Again, read and understand
the safety information provided with your system before you continue. It is very
important that you remain aware of hazards that apply to your system.
Other MTS manualsIn addition to this manual, you may receive additional MTS manuals in paper or
electronic form.
If you have purchased a test system, it may include an MTS System
Documentation CD. This CD contains an electronic copy of the MTS manuals
that pertain to your test system, including hydraulic and mechanical component
manuals, assembly drawings and parts lists, and operation and preventive
maintenance manuals. Controller and application software manuals are typically
included on the software CD distribution disc(s).
SWIFT 30 SensorsPreface
11
Conventions
DANGER
WARNING
CAUTION
Conventions
Documentation Conventions
The following paragraphs describe some of the conventions that are used in your
MTS manuals.
Hazard conventionsAs necessary, hazard notices may be embedded in this manual. These notices
contain safety information that is specific to the task to be performed. Hazard
notices immediately precede the step or procedure that may lead to an associated
hazard. Read all hazard notices carefully and follow the directions that are given.
Three different levels of hazard notices may appear in your manuals. Following
are examples of all three levels.
NoteFor general safety information, see the safety information provided with
your system.
Danger notices indicate the presence of a hazard with a high level of risk which,
if ignored, will result in death, severe personal injury, or substantial property
damage.
Warning notices indicate the presence of a hazard with a medium level of risk
which, if ignored, can result in death, severe personal injury, or substantial
property damage.
Caution notices indicate the presence of a hazard with a low level of risk which,
if ignored, could cause moderate or minor personal injury, equipment damage, or
endanger test integrity.
NotesNotes provide additional information about operating your system or highlight
easily overlooked items. For example:
NoteResources that are put back on the hardware lists show up at the end of
the list.
Special termsThe first occurrence of special terms is shown in italics.
IllustrationsIllustrations appear in this manual to clarify text. It is important for you to be
aware that these illustrations are examples only and do not necessarily represent
your actual system configuration, test application, or software.
Electronic manual
conventions
This manual is available as an electronic document in the Portable Document
File (PDF) format. It can be viewed on any computer that has Adobe Acrobat
Reader installed.
12
Preface
SWIFT 30 Sensors
Conventions
Hypertext linksThe 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 30 SensorsPreface
13
Conventions
14
Preface
SWIFT 30 Sensors
Hardware Overview
Data
S20-25
Test Track
Laboratory Simulation
OverviewThe MTS Spinning Wheel Integrated Force Transducer (SWIFT
weight, easy-to-use transducer that enables you to conduct faster, less expensive
data acquisition and road simulation testing.
The transducer is designed for use both on the test track and in the test laboratory.
It attaches to the test vehicle or an MTS Series 329 Road Simulator using an
adapter and a modified wheel rim.
You can achieve excellent data correlation using the same transducer and vehicle
on the test track and on a road simulator. It is available in various sizes and
materials to fit various vehicle and loading requirements.
®
) is a light-
ContentsSpinning Applications (Test Track) 16
Non-spinning Applications (Simulation Lab) 17
Construction 18
Design Features 22
Coordinate System 23
Specifications 25
Calibration 29
Transducer Interface 31
TI Front Panel 34
TI Rear Panel 41
TI Jumpers 42
Interfacing with RPC 43
SWIFT 30 SensorsHardware Overview
15
Spinning Applications (Test Track)
Customer Supplied
12 Vdc Power Supply
Customer Supplied
Data Recorder
Transducer Interface
(TI)
Transducer Signals
Output
Signals
S20-26
Spinning Applications (Test Track)
The SWIFT sensor can be used for road load data acquisition (RLDA)
applications:
•Durability
•Noise, Vibration and Harshness (NVH)
•Ride and Handling
•Tire Performance
The transducer is durable enough to withstand harsh road testing and data
acquisition environments. The transducer is splash resistant and suitable for use
in conditions where the test vehicle will encounter occasional standing or running
water, or will be exposed to precipitation. However, it should not be submerged.
In a typical spinning application, the transducer is mounted on a modified rim of
a tire on a test vehicle, as shown in the following figure. The Transducer
Interface (TI), power supply, and data recorder can be located inside the vehicle
or in the trunk..
Hardware Overview
16
Spinning Application (Test Track)
SWIFT 30 Sensors
Non-spinning Applications (Simulation Lab)
12 Vdc Power Supply
(with 4 connections)
Customer Supplied
Data Recorder
Transducer Interface
(TI)
Transducer Signals
Output
Signals
PC
Communication
S20-27
Non-spinning Applications (Simulation Lab)
The SWIFT sensor can be fully integrated into the simulation process, since it is
an optimal feedback transducer for use with MTS Remote Parameter Control
®
) software. The transducer takes data at points where fixturing inputs are
(RPC
located rather than at traditional instrumentation points along the vehicle’s
suspension. Using the SWIFT sensor saves you instrumentation time, and fewer
iterations are required to achieve good simulation accuracy.
Measuring spindle loads allows engineers to generate generic road profiles.
Generic road profiles are portable across various vehicle models, do not require
new test track load measurements for each vehicle, and eliminate additional
RLDA tasks.
Four of the six loads measured by the transducer directly correlate to the MTS
Model 329 Road Simulator inputs: vertical force, longitudinal force, lateral force,
and braking input.
The same transducers used to collect road data at the test track can be mounted
directly in the wheel adapters of the MTS Model 329 Road Simulator. For
durability testing, an aluminum SWIFT sensor can be used for iterations within
the RPC process. The aluminum SWIFT sensor should then be removed for the
durability cycles, to preserve its fatigue life. It can be replaced by an adapter
plate, available from MTS, to duplicate the mass and center of gravity of the
actual SWIFT sensor. If a SWIFT sensor is to be used during full durability tests,
we suggest using the titanium model, which has a higher fatigue rating.
®
In a typical non-spinning application, a SWIFT sensor is mounted on a road
simulation test fixture, as shown in the following figure.
Non-spinning Application (Laboratory Simulation)
SWIFT 30 SensorsHardware Overview
17
Construction
S20-03
Transducer
Hub Adapter
Slip Ring
(with Encoder)
Modified
Wheel Rim
Slip Ring
Bracket
(Spider)
Construction
The SWIFT sensor has one-piece construction for outstanding fatigue life, low
hysteresis, and high stiffness. Its compact package has a minimal effect on inertia
calculations, and a minimal dynamic effect on the test vehicle.
The transducer can be used for developing conventional durability tests on the
MTS Model 329 Road Simulator. Normally, the transducer is replaced with an
equivalent wheel adapter after the simulation drive signals are developed and
prior to the start of the test.
The SWIFT sensor includes several mechanical and electrical components.
TransducerThe transducer attaches directly to a modified wheel rim. On the test track, it
spins with the wheel. It does not spin on a road simulator. The transducer is
available in two materials: aluminum for spinning applications where the priority
is on light weight, and titanium for non-spinning applications, where the priority
is on durability.
The transducer’s unibody design means there are no multiple parts welded or
screwed together.
The transducer has four beams with strain gages that measure six orthogonal
outputs:
Fx—longitudinal force
Fy—lateral force
Fz—vertical force
Mx—overturning moment
My—acceleration and brake torque
Mz—steering moment
It has onboard conditioning and amplifiers to improve the signal-to-noise ratio.
Hardware Overview
18
SWIFT 30 Sensors
Construction
(Components exaggerated to show detail)
Slip
Ring
Slip Ring Bracket
(Spider)
Transducer
Interface
Cable
Anti-rotate Device
(Bend to fit vehicle)
Transducer
Customer-supplied
Attachment Bracket
Tire
Wheel Rim
Customer-supplied
Rim Adapter Flange
Hub
Adapter
Attach to
vehicle
suspension
S20-04
Hub adapterThe hub adapter attaches to the inner diameter of the transducer, allowing you to
place it at the original position of the spindle face of the vehicle. The hub adapter
enables you to maintain the original position of the tire on the vehicle while the
transducer is attached to the vehicle (the tire will not protrude from the vehicle).
Components Set Up for Test Track
Slip ring bracket
(spider)
The slip ring bracket (also referred to as the “spider”) is used to attach the slip
ring to the transducer. It has internal wiring that provides excitation power to the
strain gage bridges and brings signals out from the transducer to the slip ring.
EncoderAn encoder measures the angular position of the transducer. The SWIFT sensor
uses an optical encoder, integrated into the slip ring assembly, that counts off
“ticks” to measure the angular position as the wheel rotates. It measures 2048
(512 plus quadrature) points per revolution (ppr) with a resolution of 0.18
degrees and an accuracy of 0.18 degrees.
Slip ringThe slip ring allows you to output the transducer bridge signals and angular
position to the TI. A transducer data cable attaches from the slip ring to the back
panel of the TI. The slip ring is not used for non-spinning applications.
Anti-rotate deviceThe anti-rotate device is attached to the slip ring and the vehicle’s suspension (or
other non-rotating point). It is able to move up and down with the vehicle. Its
primary function is to provide a fixed reference point for the optical encoder. Its
secondary function is to prevent the cable from rotating with the wheel and
becoming tangled or breaking.
The anti-rotate device is mainly used for road data collection. Although it can
also be used for short periods of time on a road simulator. MTS does not
recommend this use. Due to the extreme fatigue loading characteristics of
durability testing on road simulators, we suggest that you either remove the slip
ring assembly before installing the vehicle on a road simulator, or use it only for
iteration passes, then promptly remove it.
SWIFT 30 SensorsHardware Overview
19
Construction
Wheel Well
A jarring motion
will damage the
slip ring
Allow enough clearance
for all loading and
suspension travel
S20-05
Shunt B
Shunt A
Accelerometer
(optional)
Load
S30-25
Connector Housing
The anti-rotate device should be configured such that no loading occurs to the
slip ring throughout all loading and suspension travel. This means that when you
attach the anti-rotate device to the vehicle, you must consider all possible motion
of the suspension. The anti-rotate device should not bump against the wheel well
at any time; any jarring of the anti-rotate arm will damage the slip ring. For
steering axles, the anti-rotate bracket must be mounted to part of the unsprung
suspension that steers with the tire, such as the brake caliper. For additional antirotate device mounting recommendations, refer to the Anti-Rotate Customer/
User Assembly drawing at the back of this manual.
Non-spinning
connector housing
The non-spinning connector housing or the non-spinning connector bracket (both
shown below) provide a connection between the SWIFT and the TI electronics
for non-spinning use. Both assemblies incorporate rugged connectors suitable for
durability testing. The non-spinning connector housing can also include an
optional connector with built-in, tri-axial accelerometers.
Hardware Overview
20
SWIFT 30 Sensors
Construction
S30-26
Non-Spinning
Cable Assembly
Non-Spinning
Connector Bracket
Spinning
Slip Ring
Bracket
Non-Spinning
Connector Bracket
Transducer Interface
(TI)
Additional
components
The TI conditions the power supply, and uses previously stored calibration values
to convert the eight bridge outputs and the encoder signal to six non-rotating
analog outputs (Fx, Fy, Fz, Mx, My, Mz) plus an angle output. The force and
moment outputs have a value of 10 V full scale, unless a different full-scale
output is requested by a customer. The angle output is a 0–5 V sawtooth output.
Additional components that are supplied with your SWIFT sensor include shunt
and transducer data cables, TI power cable, a SWIFT Transducer Interface
Utilities disk, and the calibration file. MTS can also provide a 12 V DC power
converter for use in the test laboratory.
SWIFT 30 SensorsHardware Overview
21
Construction
Design Features
Flexure isolationThe 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 stabilityThe entire sensor is machined from a solid, specially forged billet of high
strength aluminum or titanium. The absence of bolted joints permits an efficient
transfer of heat across the sensor structure, minimizing temperature differentials
in the gaged area.
As mentioned earlier, flexure isolation allows thermal expansion with minimal
stresses.
The transducer is designed to accommodate the high temperature environments
that occur during severe driving and braking events. Individual temperature
compensation of each strain gage bridge minimize temperature induced
variations in accuracy. Since minimal electronics reside on the SWIFT sensor, it
can easily tolerate high temperatures. The temperature rating for the SWIFT
sensor is 125° C (257° F) at the spindle hub.
Temperature compensation is done on each bridge for better performance in
transient or non-uniform temperature occurrences.
Low hysteresisThe 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 noiseThe SWIFT sensor uses a slip ring rather than telemetry for the transducer output
signals. On-board amplification of the transducer bridges minimizes any slip ring
noise contribution.
Low cross talkThe 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.
Velocity informationAngular output is available from the TI when it is used in the spinning mode with
the encoder. This angular output can be used to calculate wheel velocity. In nonspinning applications, accelerometers can be integrated into the transducer
connector housing.
MTS does not supply any conditioning electronics for accelerometers. Ask your
MTS consultant for more information about this option.
Hardware Overview
22
SWIFT 30 Sensors
Coordinate System
Fx
Fy
Fz
Mz
Mx
My
Transducer
Interface
Output signals
+
10 Volts
Angular
Position
Bridge
Outputs
S20-06
+Mz
+Fz
+Fy
+My
+Mx
+Fx
Forces acting on outer ring
S20-07
In the transducer, independent strain gage bridges measure forces and moments
about three orthogonal axes. The signals are amplified to reduce the signal-tonoise ratio. An encoder signal indicates angular position, which is used to
convert raw force and moment data from the rotating transducer to a vehiclebased coordinate system. The force and moment and encoder information is sent
to the transducer interface (TI).
Coordinate System
The TI performs cross talk compensation and converts the rotating force and
moment data to a vehicle coordinate system. The result is six forces and moments
that are measured at the spindle: Fx, Fy, Fz, Mx, My, and Mz. A seventh
(angular) output is available for tire uniformity information, angular position, or
to determine wheel speed (depending on the data acquisition configuration).
The coordinate system shown below was originally loaded into the TI settings by
MTS. It uses the right-hand rule.
SWIFT 30 SensorsHardware Overview
23
Coordinate System
The SWIFT coordinate system is transducer-based, with the origin located at the
center of the transducer. Positive loads are defined as applied to the outer ring of
the transducer.
•Vertical force (Fz) is positive up
•Lateral force (Fy) is positive out of the vehicle
•Longitudinal force (Fx) is positive out of the transducer
You can change to the MTS Model 329 Road Simulator convention (lateral load
into the vehicle is always positive) or to any coordinate system by changing the
polarities in the calibration file. For instructions on how to change the coordinate
system polarities, see the chapter, “Setting up the Transducer Interface.”
Hardware Overview
24
SWIFT 30 Sensors
Specifications
SWIFT 30 Transducer Performance
P
ARAMETERSPECIFICATION
Use
SWIFT 30 A (aluminum) for
SWIFT 30 T (titanium) for
Maximum usable rpm
Maximum speed
fits rim size (usable range)
Maximum hub bolt circle diameter
accommodates M12 or 1/2 inch studs
* A special flange configuration is required for a 12 inch wheel. Larger diameter rims can be used,
providing that overall clearance from brake calipers and suspension components is maintained.
† Load impedance >1 kΩ; 0.01 µF (maximum) load capacitance.
‡ The actual calibrated range may be different based on individual customer requirements. Consult the
calibration range sheet that accompanies each transducer for the correct calibration range.
§ Typical value on most steel rims. Aluminum rims typically have slightly higher modulation, but at a lower
added weight.
# Each SWIFT sensor is calibrated on an MTS calibration machine. MTS provides complete documentation
of calibration values for each SWIFT unit
SWIFT 30 SensorsHardware Overview
25
Specifications
Transducer Center-of-Gravity
Transducer Center-of-Gravity and Inertia Specifications
ATERIAL
M
ALUMINUMTITANIUM
Xcg0.0 mm0.0 in0.0 mm0.0 in
Ycg26.3 mm1.035 in26.3 mm1.035 in
Zcg0.0 mm0.0 in0.0 mm0.0 in
181 lb·in
94 lb·in
2
441 kg·cm2151 lb·in
2
854 kg·cm2292 lb·in
2
441 kg·cm2151 lb·in
Ixx
Iyy
Izz
274 kg·cm294 lb·in
530 kg·cm
274 kg·cm
2
2
Transducer Interface (part 1 of 2)
P
ARAMETERSPECIFICATION
Physical
Height
Width
Depth
Weight
Rack Mounting Kit
31.75 mm (1.25 in)
431.8 mm (17 in)
215.9 mm (8.5 in.)
1.68 kg (3 lb 11.1 oz)
Optional
2
2
2
*
Environmental
Ambient temperature
Relative humidity
Hardware Overview
26
0° C (32° F) to 50° C (122° F)
0 to 85%, non-condensing
SWIFT 30 Sensors
Transducer Interface (part 2 of 2)
P
ARAMETERSPECIFICATION
Power Requirements
Input voltage
Supply current
Fuse
Angular velocity
Encoder limit
Processing limit
Encoder resolution
10–17 V DC
2 A typical, 3 A maximum at 12 V DC
3 A fast-blow
2,200 rpm maximum
10,000 rpm maximum
2048 counts per revolution
(512 pulses with quadrature)
Specifications
Time delay (encoder tick to main output stable)
Transducer cable length
Shunt cable length
Analog outputs
Vol tag e
12 µs (typical)
100 ft maximum
100 ft maximum
±10 V range† (force and moment outputs)
0–5 V sawtooth (angle output)
Capacitive load
Current
Noise at output, with typical gains
0.01 µF maximum
6 mA maximum
7 mVpp, DC - 500 Hz (typical)
15 mVpp, DC - 500 Hz (maximum)
Bandwidth (bridge input to main output)
–3 dB at 30.1 kHz (typical)
90 degree at 16.6 kHz (typical)
* Add 25.4 mm (1.0 in) for ground lugs.
† Standard from MTS. Other full scale voltages can be evaluated and may be provided at special
Isolated RS-232 or RS-485 remote host connection
Isolated RS-485 TI to TI connection
Maximum number of devices that can be part
of a RS-485 multidrop chain
Maximum cable length
32 with RS-232 remote host
31 with RS-485 remote host
*
For RS-232 host:
50 ft from host to the first (nearest) TI,
and
300 ft from the first TI to the last SWIFT TI in the RS485 multidrop chain
For RS-485 host:
300 ft from host to the last (furthest) TI in the RS-485
multidrop chain
* Includes all compatible devices, such as an MTS 407 Controller. A maximum of only nine transducer
interfaces can be connected, because the addresses are limited to 1–9.
Hardware Overview
28
SWIFT 30 Sensors
Calibration
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 located at the back of each TI box.
The calibration file is loaded into the TI non-volatile RAM by MTS before the
transducer is shipped. A copy of the file is also provided on a diskette.
MTS verifies the calibration by applying loads to the transducer, measuring the
main outputs and checking for accuracy. Final calibration reports are provided
with each transducer.
Shunt calibrationAt the end of the calibration process, a shunt calibration is performed. During a
shunt calibration, a resistance is introduced into the bridge circuit. The difference
between the shunted and unshunted voltage is the delta shuntreference 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 shuntmeasured 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.
SWIFT 30 SensorsHardware Overview
29
Calibration
When you press the Shunt button, the associated Shunt LED lights. As the TI
automatically switches through the series of bridges, it verifies that the outputs
are within the accepted tolerance range. If all bridge shunt values fall within the
tolerance range, the Shunt LED on the front panel will go off (after several
seconds). If any bridge fails to fall within the shunt tolerance range, the LED will
blink, indicating that the shunt calibration has failed. See the chapter,
“Troubleshooting,” on page 127, for more information on dealing with shunt
The above example shows shunt data from the calibration file. This data may be
transferred, using the TIXFER program, from the transducer interface RAM to a
computer or from a computer to the transducer interface RAM. Note that items
marked ShuntDeltaMeas are uploaded from RAM, but not downloaded from the
computer. (For more information on TIXFER, see the chapter, “Software
Utilities.”
You can check the calibration of a transducer at any time by pressing the Shunt
switch. Subsequent shunt commands compare the current feedback values
against those stored in the TI. You may set the tolerance values for each TI by
editing the calibration file (see the chapter, “Setting up the Transducer Interface”,
for instructions).
If the current feedback values from a shunt calibration are outside the tolerance,
the Shunt LED blinks to indicate a failure.
Hardware Overview
30
SWIFT 30 Sensors
Transducer Interface
Fx
Fy
Fz
Mz
Mx
My
Transducer
Interface
Output signals
(± 10 Volts)
Angular
Position
Bridge
Outputs
Transducer bridge output
signals and encoder
angular position signal are
sent through slip ring
Transducer Interface
converts signals to nonspinning vehicle coordinates,
applies calibration gains and
cross talk compensation
Force, moment, and
angle analog signals
are output from
Transducer Interface
q
Angle signal
(05 Volts)
S20-08
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 any data recorder.
Transducer Interface
SWIFT 30 SensorsHardware Overview
Cross talk
compensation
Cross talk occurs when a force is applied to one axis, but a non-real force is
measured on another axis. The SWIFT sensor design has very low inherent cross
talk. The TI compensates for any cross talk by subtracting the non-real forces
when the amount of cross talk is known.
The amount of known cross talk is determined during the calibration process.
Cross talk values will vary slightly for different rims. For example, a steel rim
will have slightly different cross talk errors than a less rigid aluminum rim.
Signal conditioningThe 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).
31
Transducer Interface
Fx1
Fx2
Fy1
Fy2
Fy3
Fy4
Fz1
Fz2
Fx
Fy
Fz
Mx
My
Mz
Geometric
Matrix
Zero and
Scaling
q
Cross
Coupling
Matrix
Rotational
Transformation
q
InputsOutputs
Transducer Interface Functions
S20-09
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
•In spinning applications, using a rotational transformation to put the forces
and moments into a stationary reference frame
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 output (θ)
Analog signalsThe force and moment signals are output from the TI in the form of ±10 V
scale analog signals. These signals can be used by any data acquisition system.
The angle output is an analog voltage that is proportional to angular position. At
0° the output is 0 V. At 360°, the output is 5 V.
1
full
32
Hardware Overview
1.Standard from MTS. Other full-scale output voltages can be evaluated and may be
provided at special request.
SWIFT 30 Sensors
Transducer Interface
0360°
5V
0°360°
q
Angle
Output
1 rev = 360°
S20-10
The angle output for a tire rotating at constant velocity can be represented by the
following illustration:
Although you may not routinely use it, the angle output information is available
for tasks such as tire uniformity testing and troubleshooting. You may also
calculate angular velocity by measuring the frequency of the angle output signal.
CommunicationsThe TI provides a serial port for remote communication. The port allows
connection to an RS-232 or RS-485 host for multidrop communication. This
interface is compatible with the MTS 407 Controller protocol, and 407
Controllers may also be in the same multidrop communication chain. A
multidrop configuration can include up to 32 total devices in any combination,
with a maximum of nine TIs (limited to addresses 1 through 9).
The serial interface provides the following capabilities:
•allows the user to save and restore TI setup parameters.
•is compatible with LabVIEW®.
•is compatible with serial port-equipped computers (UNIX machines,
Macintosh, and IBM PC).
•is able to link multiple TIs (and 407 Controllers) to one host computer.
SWIFT 30 SensorsHardware Overview
33
Transducer Interface
S20-11
Fuse
Power Switch
and Indicator
Shunt Switch
and Indicator
Angle Zero
Switch and Indicator
Bridge Zero
Switch and Indicator
Fail
Indicator
Transmit
Indicator
Address
Selector
TI Front Panel
Fuse (F1)A 3A fuse protects the electronics.
Transducer Interface Front Panel
Power switch and
Indicator
The power switch turns power on and off. A green indicator will light to indicate
that the TI power is turned on.
Shunt switchPressing this switch performs a shunt calibration (shunt cal) of the transducer.
You do not need to hold the switch in continuously, only until the Shunt indicator
lights up (indicating that the TI has started the shunt cal).
Before you perform a shunt cal, check that the appropriate shunt reference value
and error tolerance have been downloaded (these values are normally loaded
during system calibration, and are referred to as the shunt delta cal values).
A shunt calibration will determine the current delta values by measuring the
bridges unshunted and shunted, and then compare these values to the previously
loaded calibration values. If the measured values are outside of an acceptable
tolerance, the Shunt indicator will flash, indicating an error.
Shunt IndicatorThis indicator indicates the current state of the shunts. If there are any active
shunts, or if you are currently performing a shunt calibration, this indicator will
be lit.
If the shunt cal check fails, this indicator flashes (at approximately a 1 Hz rate).
NoteThe state of the shunt cal check is cleared at power-up, so the shunt cal
should be performed when the system installation is in question.
Hardware Overview
34
SWIFT 30 Sensors
Transducer Interface
[SWIFT]
Name=zero 3 after new tire
SerialNum=1234567
Normalization=0
InputSwitches=255
OutputPolarities=40
ZeroAlgorithm=3
AngleMode=0
AngleOffset=82.0898
AngleFixed=0
ZFX1=0.103786
ZFX2=-0.023199
ZFY1=-0.094017
Angle Zero and Bridge
Zero switches
These switches are used to zero the transducer inputs. Which switch you press
depends on the ZeroAlgorithm that you specified in the calibration file (see
following illustration). Two different methods are used to zero the system:
spinning and non-spinning. For more detailed information on selecting a zero
method, see the chapter, “Setting up the Transducer Interface.”
When you select a zero method, it will activate the appropriate switch on the TI
front panel. Each switch performs a specific zero function:
Angle Zero– Angle offsets are required for spinning applications only. This
switch is active when the ZeroAlgorithm=1, or 3. The TI reads the current angle
and compensates for any offset from the Z axis facing up. You will not use this
switch for non-spinning applications.
Bridge Zero–Bridge offsets are required for both spinning and non-spinning
applications. This switch is active when the ZeroAlgorithm=0, 1, or 3. The TI
reads the transducer bridge values and compensates for any offsets so that the
bridge output is 0 at 0.0V.
SWIFT 30 SensorsHardware Overview
35
Transducer Interface
When a system zero is initiated, the associated LED is lit. After successful
completion of the system zero, the LED turns off. If there is a failure during the
system zero, the LED will flash at approximately a 1 Hz rate.
Angle Zero and Bridge Zero Switch Functions
Z
ERO ALGORITHMWHENTO USEANGLE ZEROBRIDGE ZERO
0
(Preferred method for
non-spinning
applications)
1
Use this algorithm for
non-spinning (fixed)
applications.
Use this algorithm for
spinning applications.
You will need to
mechanically level the
The Angle Zero switch is
non-functional.
Press the Angle Zero
switch to read the current
angle and use the value to
set the angle sum to 0.0°.
Press the Bridge Zero
switch to measure the
static transducer bridge
offsets.
Press the Bridge Zero
switch to measure the
static transducer bridge
offsets.
SWIFT sensor.
3
Use this algorithm for
spinning applications.
You do not need to
mechanically level the
Both the Angle Zero and Bridge Zero switches are
functional. This algorithm will perform both angle zero
and bridge zero processes regardless of which button
you press.
SWIFT sensor.
4
(Preferred method for
spinning applications)
Use this algorithm for
spinning applications.
You will need to
Both the Angle Zero and Bridge Zero switches are
functional. This algorithm will perform both angle zero
and bridge zero processes.
mechanically level the
SWIFT sensor.
Hardware Overview
36
SWIFT 30 Sensors
Transducer Interface
Zero LEDsThese indicators indicate the current state of the zero process. The
ZeroAlgorithm value (0, 1, 3, or 4) you selected in the calibration file will
determine the state of the indicators when you press either the Bridge Zero or the
Angle Zero button.
•The indicators are off under normal operating conditions
•In non-spinning applications using ZeroAlgorithm=0 (required), press the
Bridge Zero button. The Bridge Zero indicator will light for 3–4 seconds
while the TI is completing the bridge zero process.
•In spinning applications using ZeroAlgorithm=1 (alternate), pressing the
Bridge Zero button will light the Bridge Zero indicator continuously (no
flashing) until the wheel is spun for one revolution (index-to-index). This
may take up to two full revolutions, depending on where the encoder index
pulse starts. After one revolution of data is collected, the Bridge Zero
indicator will flash rapidly for 30 seconds while the data is analyzed and the
bridge zeroes are calculated.
When you press the Angle Zero switch, the Angle Zero indicator will light
for a few seconds while the TI reads the current angle and sets the angle
offset value.
•In spinning applications using ZeroAlgorithm=3 (alternate), both the
Bridge Zero and Angle Zero indicators will light continuously until the
wheel is spun for one revolution (index-to-index). After one revolution of
data is collected, both indicators will blink rapidly for approximately two
minutes while the TI analyzes the data and calculates both the angle offset
and bridge zero values.
•In spinning applications using ZeroAlgorithm=4 (preferred), the Bridge
Zero and Angle Zero indicators will initially be off. After the wheel is
turned at least 1.25 turns in order for the TI to locate the index, the level can
be installed and leveled. When the Bridge Zero button is pressed, the
Bridge Zero indicator will light continuously for a few seconds, then start
blinking rapidly. The Angle Zero indicator will start blinking slowly.
When you press the Angle Zero button, the Angle Zero indicator will light
continuously for a few seconds. Then both the Bridge Zero and Angle Zero
indicators will turn off.
If the algorithm was unable to calculate zero, the Fail indicator will light
momentarily and both the Bridge Zero and Angle Zero indicators will
blink continuously at approximately a 1 Hz rate.
•If no successful zero has been performed for the currently selected zero
algorithm, the Bridge Zero and Angle Zero indicators will flash (at
approximately a 1 Hz rate), until a zero has been initiated. Use the
TISTATUS utility for a detailed explanation of the problem.
After successful completion of a zero algorithm, the Bridge Zero and Angle Zero indicators turn off. Should the system zero fail, the indicators will return to
a flashing state.
SWIFT 30 SensorsHardware Overview
37
Transducer Interface
Address selectorEach TI in a communications chain has a unique address. This address is used in
every read or write command from the host computer. The host can transmit to
only one TI at a time, using its assigned address. The TI will reply to the host
when it has received a command.
The address selector switch allows you to set the communication address for the
TI. When multiple TIs are connected, each must have a unique address. The
address must be 1 to 9. Address 0 is used only for broadcast messages from the
host. In the case of broadcast messages, the TI does not respond to the host.
To change an address, insert a small screwdriver in the slot and turn the dial until
the arrow points to the desired address number.
NoteMake sure every TI on a communications chain has a unique address. If
you set two TIs on one communications chain to the same address, you
may experience unpredictable communications errors.
If two TIs on one communications chain have the same address, communications
to either TI will be unreliable. (The errors are unpredictable, but will probably be
parity or framing errors.) Assigning the same address to two TIs does not damage
the hardware.
Transmit IndicatorThe green Transmit indicator lights to indicate that the TI is transmitting
information via the COMM IN connector.
FAIL IndicatorThe red Fail indicator lights to indicate that a fail condition exists on the board.
Depending on the failure detected, the Fail indicator will either be on constantly
or will flash a repetitive pattern that can be used to identify the failure detected.
Certain failures are considered critical, and will result in the TI becoming
completely unusable. These failure conditions must be resolved before the TI can
be used. If a critical failure occurs, the Fail indicator will only blink the cause of
the first critical failure. This failure code will be repeated approximately every 1
second.
Non-critical failures indicate impaired system functionality, which, in most
cases, can be corrected operationally from the communication interface. Noncritical failure codes are checked cyclically, so that multiple failure conditions
can be communicated. Failure codes are indicated approximately every 1.5
seconds.
The following table lists fail conditions and the manner in which the Fail
indicator indicates the failure.
Hardware Overview
38
SWIFT 30 Sensors
F
AIL INDICATOR STATE
[NUMBEROFBLINKS:]
Transducer Interface
Error Codes for the Fail Indicator (part 1 of 2)
ERROR
Off
Continuous On
Fast blinking
Fast varying blink
1
2
3
5
6
7
8
No error detected
Critical: Boot failure; bad code in boot block
Critical: Unanticipated exception prior to relocation of loader code
Critical: Unanticipated exception after relocation of loader code
Critical: SRAM failure
Critical: Local register failure
Critical: Boot block CRC failure
NVRAM error. An error was detected during the NVRAM self-test. This self-test is
performed at every power-cycle, and verifies that the NVRAM checksum is valid, and
also that the data stored is compatible with the current firmware version. A failure of
this test will require an NVRAM Init command to be issued. Issuing this command
will result in all stored settings being cleared.
Self-Test fail. A failure was detected during the commanded self-test (note that this is
different than the power-up self-test). Further information can be obtained by reading
the self-test error status.
Operational error. These errors are usually caused by issuing communication
commands with invalid Command IDs, out-of-range data, invalid slot number, and so
on. This error condition is cleared after the Fail indicator has indicated it.
Serial EEPROM Error. A checksum or version error was detected on the serial
EEPROM data. This data stores normalization values.
9
10
11
12
13
14
15
16
17
AD Failure. An error (gain out of range or offset out of range) occurred on at least one
A/D, when the A/D gains and offsets were set. The ability to perform a zero, self-test
or shunt tests may be impaired in this state.
Issuing a Cal A/D command may clear this state.
Critical: Memory allocation failure
Critical: An unexpected interrupt occurred.
Communication Interface Init Error. An error occurred while attempting to initialize
the communication interface. The communication interface may be unusable in this
state.
TI Firmware Init Error. An error occurred while attempting to initialize the TI
firmware. The communication interface may be unusable in this state.
Box ID Error. An error occurred while attempting to initialize the TI Box ID. The
communication interface may be unusable in this state.
DAC Init Error. An error occurred while attempting to initialize the TI DACs. The
functionality of the TI may be impaired in this state.
Switch Init Error. An error occurred while attempting to initialize the TI switches. The
functionality of the TI may be impaired in this state.
Encoder Init Error. An error occurred while attempting to initialize the TI encoder
interface. The functionality of the TI may be impaired in this state.
SWIFT 30 SensorsHardware Overview
39
Transducer Interface
AIL INDICATOR STATE
F
[NUMBEROFBLINKS:]
18
Error Codes for the Fail Indicator (part 2 of 2)
ERROR
AD Init Error. An error occurred while attempting to initialize the TI A/Ds. The
ability to perform a self-test, and/or shunt tests may be impaired in this state.
19
Shunt interface Init error. An error while attempting to initialize the shunt interface.
The shunt interface may be unusable in this state.
Hardware Overview
40
SWIFT 30 Sensors
Transducer Interface
J2A Shunt A
and J2B Shunt B
J4 Output
Comm In and
Comm Out
J3 Power
Ground
Terminals
Transducer
Connector
S20-12
TI Rear Panel
Transducer Interface Rear Panel
J4 Output connectorThe J4 Output connector provides the conditioned sensor outputs that can be
connected to a data acquisition or test control system.
Transducer connectorConnect the data cable from the transducer slip ring to the Transducer Connector.
J2A Shunt A
J2B Shunt B
The J2 connectors are used for the shunt cables. The shunt cables are connected
to the two 6-pin shunt cal connectors on the front of the transducer.
connectors
Comm InComm In is an 8-pin modular phone jack connector (RJ-45) that provides a
connection to an RS-232/RS-485 remote host, or to another TI in an RS-485
multidrop communications chain. The cable connected to Comm In selects an
RS-232 or RS-485 interface. The RS-232/RS-485 interfaces on Comm In are
electrically isolated from the TI power. This connection is only needed when you
are downloading new settings to the TI module.
Under normal operating conditions, no host connection is required. The Comm In and Comm Out connectors allow you to daisy-chain multiple boxes without
Y cables or multiple connections to the host computer.
Comm OutComm Out is an 8-pin modular phone jack connector (RJ-45) that provides a
connection to another TI chassis in an RS-485 multidrop communication chain.
J3 Power connectorConnect a power cable from an external 12 V DC source.
Ground TerminalsThe ground terminals enable you to ground the TI, and chain several TI boxes
together.
SWIFT 30 SensorsHardware Overview
41
Transducer Interface
X2
X1
X4
X5
X6
S20-13
TI Jumpers
J
UMPERSETTINGFUNCTION
The transducer interface uses circuit board jumpers to establish certain
parameters and make use of various electronic functions. These jumpers are set at
the factory, and should not be reset. The following table is for reference only.
X1
1–2
2–3
X2
1–2
2–3
X4removed
X5installed
removed
X6installed
removed
Excitation setup for shunts FX1, FY1, FY4, and FZ2.
Sets up – (minus) excitation for shunts FX1, FY1, FY4, and FZ2.
Sets up + (plus) excitation for shunts FX1, FY1, FY4, and FZ2.
Excitation setup for shunts FX2, FY2, FY43 and FZ1.
Sets up – (minus) excitation for shunts FX2, FY2, FY43 and FZ1.
Sets up + (plus) excitation for shunts FX2, FY2, FY43 and FZ1.
Not used for TI applications (Standard setting).
Enables the ability to download new code to the block of FLASH
RAM where the boot code is stored.
Disables the ability to download new code to the block of FLASH
RAM where the boot code is stored (Standard setting).
Boots to the FLASH memory down-loader.
Boots to the Transducer Interface software (Standard setting).
Hardware Overview
42
TI PWB Jumper Locations
SWIFT 30 Sensors
Interfacing with RPC
The SWIFT sensor is directly compatible with the MTS Remote Parameter
Control (RPC) simulation software. The SWIFT system produces outputs that
directly correspond to the uncoupled spindle forces that the MTS Model 329
Road Simulator applies to the vehicle. Traditional instrumentation techniques
provide coupled suspension loads data. Using the SWIFT sensor, the RPC
simulation software needs to apply less correction to obtain the road simulator
drive signals. Fewer iterations are required to recreate the measured loads.
You must ensure that the full scale value for your data recorder and the MTS
Series 498 electronics match. MTS electronics are typically set at ±10 V full
scale, while some data recorders are ±5 V full scale.
The SWIFT sensor is calibrated for ±10 V full scale. To recompute the TI gains
for ±5 V full scale, a verification pass must be run or the calibration will not be
traceable. Upon special request, MTS can evaluate and may provide calibration
for ±5 V or other full scale voltages.
Interfacing with RPC
SWIFT 30 SensorsHardware Overview
43
Interfacing with RPC
Hardware Overview
44
SWIFT 30 Sensors
Software Utilities
ContentsIntroduction 46
TISTATUS - Transducer Interface Status 47
TIXFER - Transducer Interface Transfer 48
TISHUNT - Transducer Interface Shunt 50
Setting Up Shunt Calibration Reference Values 54
TISETZERO – Transducer Interface Set Zero Method 55
Error Messages 56
Shunt Error Status 57
SWIFT 30 SensorsSoftware Utilities
45
Introduction
Introduction
The SWIFT utility programs in this distribution are for Win32 Operating
Systems (Windows 95, 98, NT, 2000, XP). They are designed to be run from the
Command Prompt or MSDOS Shell. However, it is possible to create a shortcut
to run the programs. If launched from a shortcut the application window may
close immediately when the application terminates making it impossible to see
any error messages. The Command Prompt application is usually found in
Start–>Programs–>Accessories but the actual location depends on the version
of your operating system.
To run a SWIFT utility program
•Copy it to your computer. For example, create the folder
the executables (*.exe) to that folder.
•Launch Command Prompt
•Change the working directory to where you copied the executables: cd bin.
This step can be eliminated if you set up the PATH environment variable to
include the directory where you copied the SWIFT utility executables.
•Type the name of a SWIFT utility program providing the necessary
command line arguments:
provided the program will display a simple help message. This is helpful if
you forget the order of the command line arguments.
In the Windows environment the SWIFT utilities programs define port 1 as
COM1: and port 2 as COM2:. Which communications port you specify depends
on which connector on the computer the serial communications cable is plugged
into. To confuse things, some computers label the communications connectors as
“A” and “B”.
1
tixfer 1. If no command line arguments are
C:\bin and drag
2
Software Utilities
46
1. You may want to change the layout properties for the Command Prompt
window to display a larger area or to increase the screen buffer size. Within
Command Prompt, select Properties and the Layout tab to modify the
screen buffer size or window size.
2. In Windows 2000 the environment variables can be changed at
Start–>Control Panels–>Systems. Click on the Advanced tab, and the
Environment Variables… button. The path is a system variable. Adding
;c:\bin, or whatever directory name you used, to the end of the string will
cause Command Prompt to search that directory for applications.
SWIFT 30 Sensors
TISTATUS - Transducer Interface Status
TISTATUS - Transducer Interface Status
This program is used to get status information from the SWIFT Transducer
Interface (TI). When the TI has encountered a problem and is blinking an error
code, this program can be used to easily interpret the error. For certain errors this
program may provide additional information. The program also provides
information such as the internal power supply voltages.
NoteThe power supply voltages displayed may be unreliable if the power
supplies are too low, as the circuit used to measure the power supply
also depends on the available power.
SyntaxThe tistatus command requires two arguments:
tistatus port box
port is the communications serial port number
1 = COM1:
2 = COM2:
box is the TI communications address
1 = lowest possible address
9 = highest possible address
-5V Ref = -5.00763
No system errors to report
Closing the communications port...
Program completed.
SWIFT 30 SensorsSoftware Utilities
47
TIXFER - Transducer Interface Transfer
TIXFER - Transducer Interface Transfer
This program is used to change settings within the SWIFT Transducer Interface
(TI). It can be used to read the current settings and save them to the computer
(upload) or write the settings to a TI with values from a file on the computer
(download).
2...Restore/Download a box
Enter choice? 1
Enter TI box address? 1
Enter output specifications filename? example.cal
Enter description? example for uploading settings
Allocating box...
Initializing box...
File FormatThe file used with commands contains a header and a list of parameters.
Transducer calibrations can be uploaded and saved individually. If a test needs to
be rerun at a later date but the original transducer is not available, another
transducer can be used by downloading its calibration information.
The header must be the first thing in the file, and it must be in the form:
[SWIFT]
Following the header is a list of parameter settings. The syntax is:
ParamName=ParamValue
The following rules apply:
Tabs and spaces are allowed.
The parameters can occur in any order
Names are case insensitive. If a parameter name is not recognized, an error
will be reported, and further processing will be stopped.
If an error causes the program to abort while downloading, any parameters
prior to the error will have been successfully downloaded because
parameters are downloaded as they are read.
Software Utilities
48
SWIFT 30 Sensors
TIXFER - Transducer Interface Transfer
CAUTION
CAUTION
Make important files read-only after uploading. After uploading important
files, such as those containing calibration data, make them read-only.
If not protected, important data may get overwritten.
Make important files read-only, and make backups of important data.
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 TIXFER
files
The files created by TIXFER are plain text files that can be read by Microsoft
Notepad or WordPad. In general, use a common extension such as “.cal” to help
identify the files, but that is not required. The settings files contain both
configuration settings and calibration settings. As a general rule parameters that
begin with K are calibration gains and should not be edited. Configuration
settings such as the zero algorithm can be changed without affecting the
calibration.
Whenever downloading settings, make sure the file is for the transducer
connected to the SWIFT Transducer Interface. Usually the filename for the
settings contains the serial number for the transducer. If settings for one
transducer are used with another they will not be accurate. Because the 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 TIXFER 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.
All parameters within the TI have been calibrated. Because the resolution of each
adjustable parameter is finite, downloaded values may vary slightly from
subsequent uploads and the values uploaded from various units may be different.
The downloaded value gets “snapped” to the closest realizable value. The
realizable values depend on the resolution and calibration data for the parameter.
Normally the gains from the SWIFT automated calibration stand are computed to
a higher resolution than the TI is capable of dealing with.
SWIFT 30 SensorsSoftware Utilities
49
TISHUNT - Transducer Interface Shunt
TISHUNT - 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.
SyntaxThe tishunt command requires one argument, as follows:
tishunt port box
port is the communications
1 = COM1:
2 = COM2:
Example
box is the SWIFT-TI communications address
1 = lowest possible address
9 = highest possible address
Initializing box...SWIFT TI Shunt Main Menu
0...exit
1...Read current Shunt values
2...Set the TI shunt tolerance
3...Restore Shunt parameters from a file
4...Scan inputs & outputs with shunts
5...Command a shunt cal
6...Write last shunt measurements to a parameter file
Enter choice:
The Shunt Main Menu options are described in the following paragraphs.
Software Utilities
50
SWIFT 30 Sensors
TISHUNT - Transducer Interface Shunt
Option 0Use this option to exit the program.
Option 1Use this option to read the shunt tolerance, the last measured shunt values, the
reference values, and the shunt error status.
NoteThe shunt error status is not maintained over power cycles, so it is only
valid if the shunt is executed after power is applied. Refer to, “Shunt
Error Status,” on page 57.
This option asks if you want to save the data in a file. Answer Y or N, and if Y,
then supply the file name when prompted. The following is typical of what is
displayed when this selection is made:
Reading Shunt parameters from TI... OK
Shunt Delta Tol: 10.000%
FX1 Ref:3.935Measured:3.934Error Status:0
FX2 Ref:3.932Measured:3.932Error Status:0
FY1 Ref:3.937Measured:3.930Error Status:0
FY2 Ref:3.929Measured:3.930Error Status:0
FY3 Ref:3.932Measured:3.932Error Status:0
FY4 Ref:3.931Measured:3.932Error Status:0
FZ1 Ref:3.930Measured:3.935Error Status:0
FZ2 Ref:3.932Measured:3.934Error Status:0
Save to a file (y/n)?
NoteIf you save to a file, the file is created in the same directory as the tishunt
program. The file name must contain less than 80 characters.
Option 2Use this to set the shunt tolerance. When selected, the following is displayed:
The Shunt Tolerance specifies how much the measured shunt deltas may
deviate from the Ref settings, and still be considered good.
The value is entered as a percentage, where "1.0" would mean 1.0% of the
Ref settings.
For example: if the tolerance is 1%, and the Ref setting is 8.0, then the
measured delta must be between 7.92 and 8.08 to be considered good.
It is not necessary to reboot the TI when this value is changed, but a
Shunt Calibration must be executed to update the Shunt Error Status
words.
Also note that a parameter download will overwrite this value.
Enter tolerance (in percent):
SWIFT 30 SensorsSoftware Utilities
51
TISHUNT - Transducer Interface Shunt
Option 3Use this option to restore shunt settings from a file. The file format is the same as
that used in the tixfer program.
Option 4Use this option to apply a shunt sequentially, reading the eight bridges and six
outputs of the Transducer Interface. Note that this option does not update the
shunt measured values or error status. A reading is first made with no shunts
applied (displayed as the zeroes data). The remainder of the readings are
displayed as delta values from the original readings.
Enter Filename to save data to (the file will be appended):
Enter Description:
Reading bridges & outputs unshunted
Option 5Use 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.
TI Shunt Cal state 2
TI Shunt Cal state 5
TI Shunt Cal state 7
TI Shunt Cal state 8
TI Shunt Cal state 11
TI Shunt Cal state 14
TI Shunt Cal state 17
TI Shunt Cal state 20
TI Shunt Cal state 23
TI Shunt Cal state 26
TI Shunt Cal state 29
TI Shunt Cal state 32
TI Shunt Cal state 34
TI Shunt Cal state 35
TI Shunt Cal state 38
TI Shunt Cal state 41
TI Shunt Cal state 43
TI Shunt Cal state 44
TI Shunt Cal state 47
TI Shunt Cal state 0
TI Shunt Cal completed.
Read results by selecting appropriate menu option.
Option 6A valid shunt calibration should be performed prior to executing this command.
This option allows an easy means of setting the Shunt Calibration Reference
values after calibration. After this option has executed, the file that was written
can then be downloaded (using option 3). Downloading the file will set the Shunt
Reference values to the last measured values, so that subsequent Shunt
Calibrations should pass when the SWIFT system is setup properly, and fail
when not setup properly.
NoteThis menu choice should only be used by qualified service personnel.
SWIFT 30 SensorsSoftware Utilities
53
TISHUNT - Transducer Interface Shunt
Setting Up Shunt Calibration Reference Values
The tishunt utility provides all of the necessary functions for setting up a
Transducer Interface with valid Shunt Cal Reference values.
NoteThis procedure should only be performed by qualified service personnel.
Before running the tishunt utility, connect the Transducer cable and Shunt cables
from the SWIFT TI to the SWIFT Transducer Assembly. Power up the SWIFT TI
and wait for the red Fail indicator on the TI front panel to go out (this indicates
that the TI is ready).
Note that it is not necessary to perform a System (Transducer) Zero prior to the
Shunt Cal.
Procedure1. Launch the tishunt utility.
2. Using Option 2, enter the desired shunt tolerance.
3. Using Option 5, command a shunt cal, and wait for it to complete. This
causes the TI to apply and measure each shunt delta. These measured values
will be written as the Cal Reference values. The Shunt indicator on the TI
front panel should not blink (blinking indicates that the shunt cal
verification failed).
4. Using Option 1, read the current shunt parameters. It is not necessary to
save these to a file. Review the measured values and verify that they are
correct.
5. Using Option 6, write the last shunt measurements to a parameter file. This
sets up a file that contains the eight Set Shunt Cal Reference commands,
with the last measured values as the values for the commands. This step
does not download the values, but forces the generation of a shunt cal
reference parameter file.
Write down the filename that is generated, as it will be required later.
6. Using Option 3, restore shunt parameters from a file. Enter the filename
used in Option 6 (Step 5). The tishunt utility then downloads the shunt cal
reference values to the TI. These values are written into non-volatile
memory within the TI, and are automatically restored whenever the TI is
powered up.
7. Using Option 5, command another shunt cal, and wait for it to complete.
This provides a verification, showing that the values downloaded are valid.
The Shunt indicator on the TI Front Panel should not blink (blinking indicates
that the shunt cal verification failed).
Software Utilities
54
SWIFT 30 Sensors
TISETZERO – Transducer Interface Set Zero Method
TISETZERO – Transducer Interface Set Zero Method
This program allows some configuration settings to be changed in a SWIFT
Transducer Interface (TI) without modifying a settings file. This program only
changes configuration settings, it does not change any calibration settings.
Syntax:
tisetzero port box [zero_algo]
port is the communications
1 = COM1:
2 = COM2:
box is the TI communications address
1 = lowest possible address
9 = highest possible address
zero_algo is optional and specifies the zero algorithm
0 = lowest
4 = highest
Example
C:\bin>tisetzero 1 1
Firmware Version: 2.6.1
Current angle mode is ENCODER
Current zero algorithm is SPINNING BRIDGE AND ANGLE
UNLOADED
Zero algorithms...
0) exit
1) fixed
2) spinning bridge
3) spinning bridge and angle unloaded
4) spinning 2 point
Enter choice?
Option 0
Use this option to exit the program
Option 1Use this option for fixed (non-spinning) applications. It sets the AngleMode to 1
(fixed) and the ZeroAlgorithm to 0 (fixed). You may need to set the fixed angle
manually.
Option 2Use this option for spinning applications. It sets the AngleMode to 0 (encoder)
and the ZeroAlgorithm to 1 (spinning bridge, angle with level).
Option 3Use this option for spinning applications. It sets the AngleMode to 0 (encoder)
and the ZeroAlgorithm to 3 (spinning bridge and angle)
Option 4Use this option for spinning applications. It sets the AngleMode to 0 (encoder)
and the ZeroAlgorithm to 4 (2-point bridge and angle with level).
SWIFT 30 SensorsSoftware Utilities
55
Error Messages
Error Messages
When a SWIFT utility encounters an error, a traceback message is displayed. An
example traceback message is:
serial port command timeout, received: 0 chars, buffer:
-1: (DoTIUploadBox) upload box error
-1: (SwiftTI::Init) error reading typeid
-1: (MParm::ReadVal) error read value for Type ID
-1: (MPort::DoCommand) error sending or receiving response
-4: (MPort::GetResponse) error parsing error code
-4: (ParseErrorCode) expected @
Usually you only need to be concerned with the first line of the traceback which
gives a summary of the error. The indented list of messages may provide
additional information that in some instances will be helpful to determine the
cause of an error. For instance, if the program reported an “out of range” error
one of the other lines may indicate the name of the parameter being written to
when the error occurred.
The number at the beginning of an indented error line is an error number.
Negative error numbers are generated by the SWIFT utility program. Positive
error numbers are generated by the TI.
Software Utilities
56
SWIFT 30 Sensors
Shunt Error Status
This is the error status for each bridge from the last shunt cal that was performed.
The error status is a bit-mapped status word, where the error is present if the bit is
set to 1.
Bit 0 = Bridge amplifier was saturated prior to applying the shunt.
Bit 1 = Bridge amplifier was saturated after applying the shunt.
Bit 2 = Measured delta value failed high.
Bit 3 = Measured delta value failed low.
Bit 4 = A procedural error occurred (unable to read a value, etc.).
In the following example the error status received is 5 indicating that bits 0 and 2
were set.
Bit4 3210
Shunt Error Status
Bit Value168421
Example0 0101
Error Status=
5
SWIFT 30 SensorsSoftware Utilities
57
Shunt Error Status
Software Utilities
58
SWIFT 30 Sensors
Setting up the Transducer Interface
OverviewTwo different software configurations are used by the TI, depending on whether
you will be using the SWIFT sensor on the test track (spinning application) or in
the laboratory (non-spinning application). Angular transformation is required on
the test track only. If you are using the same transducer and TI for data collection
and simulation testing, you must change the software configuration before the TI
can be used for simulation testing.
ContentsSelect a Zero Method 60
Calibration File Elements 61
Zero Algorithms 62
Upload the Calibration File 64
Edit the Calibration File 66
Download the Calibration File 70
SWIFT 30 SensorsSetting up the Transducer Interface
59
Select a Zero Method
Select a Zero Method
Before you install a transducer and zero it, you must configure the transducer
interface (TI) for the appropriate zero method.
Equipment requiredYou will need:
•A laptop computer (at test track) or desktop PC
•Serial port communication cable
•SWIFT Transducer Interface Utilities diskette
•Know the address assigned to each TI box
•Some experience with DOS commands and text editors
Zero methodsThere are two separate zero algorithm classes used to zero the transducer inputs.
The method you choose depends on whether you will use the transducer in a
spinning (test track) application (Zero Algorithm 1, 3 or 4) or non-spinning (road
simulator) application (Zero Algorithm 0).
If you are using the same transducer with a road simulator that you used
previously on the test track, you must re-zero the transducer using the nonspinning zero algorithm.
When you select an algorithm, you are also enabling the zero button(s) on the
front panel of the TI. There are two zero buttons:
Bridge Zero
Angle Zero
What you need to doTo change the zero algorithm used by the TI you will need to:
1. Copy the original calibration file from the diskette that came with the
transducer to the computer.
2. Edit the calibration file to select a zero algorithm and angle mode.
3. Download the modified calibration file from the computer to the TI box.
4. Repeat the process for all of the transducers.
These steps are described in detail in the following sections.
The following figure shows some elements of the calibration file:
Select a Zero Method
SWIFT 30 SensorsSetting up the Transducer Interface
Items you may edit•OutputPolarities—defines the polarities of the six outputs. Change these
•ZeroAlgorithm—selects a zero algorithm for the application.
•AngleMode—selects the mode used for determining the encoder sine and
•AngleFixed—used for non-spinning applications.
•AngleOffset— used for spinning applications. Normally you do not need to
•EncoderSize
Typical Calibration File
only if your application requires different polarities from those on the
transducer label.
cosine.
change this value.
depending on whether the application is using telemetry (0) or spinning slip
1
–defines the size of the encoder. The value will vary
ring (1).
1. Some older versions of TI electronics may have firmware versions that are
not compatible with this parameter. If you are not using telemetry, this will
not affect the function of the SWIFT. To allow proper function, load a
current version of TIXFER or delete this line from the calibration file.
61
Select a Zero Method
Zero Algorithms
The following table lists the different values available and the angle zero
and bridge zero functions that they perform:
Zero Algorithm Values Defined (part 1 of 2)
ERO ALGORITHM WHENTO USEBRIDGE ZEROANGLE ZERO
Z
0
1
Use this algorithm for
non-spinning (road
simulator) applications.
(AngleMode=1)
Use this algorithm for
spinning (test track)
applications.
You will need to
mechanically level the
SWIFT sensor.
The transducer is
unloaded during the
zero process.
(AngleMode=0)
When you press the Bridge Zero button, the TI measures
the static transducer bridge
offsets. It sets up zero DACs
to provide 0.0 V raw bridge
output.
The Bridge Zero LED will
light for 3–4 seconds, and
will go off when the zero
process is complete.
When you press the Bridge Zero button, the TI will
collect one revolution of raw
bridge data, average the data,
and remove the DC offset by
setting the zero DACs to the
average value.
The Bridge Zero LED will
light continuously until the
wheel is turned for one
revolution (index-to-index).
After one revolution of data
is collect, it will flash (at
approximately 4 Hz) for 30
seconds while the bridge
zero values are computed.
The Angle Zero button is nonfunctional.
When you press the Angle Zero
button, the TI will read the current
angle and use the value to set the
angle sum to 0.0 degrees.
The Angle Zero LED will light
for a few seconds while the TI sets
the angle offset value.
If you do not press the Angle Zero
button, the value for AngleOffset
will not be updated in the
calibration file.
The wheel must be rotated past the
encoder index pulse at least once
after power up so that the
electronics can determine the
absolute angular position.
2
Setting up the Transducer Interface
62
Reserved for future use. N/AN/A
SWIFT 30 Sensors
Zero Algorithm Values Defined (part 2 of 2)
Z
ERO ALGORITHM WHENTO USEBRIDGE ZEROANGLE ZERO
Select a Zero Method
3
Use this algorithm if
you do not need to
mechanically level the
Both the Angle Zero and Bridge Zero buttons are functional.
This algorithm will perform both angle zero and bridge zero
processes.
SWIFT sensor
The transducer is
unloaded during the
zero process.
(AngleMode=0)
In the Bridge Zero process,
the TI will average the data
and remove the DC offset by
setting the zero DACs to the
average value.
In the Angle Zero process, the TI
will collect one revolution of raw
bridge data, perform a peak/valley
analysis via sine curve fit for X1,
X2, Z1, Z2, and determine the
angle that will result in positive Z
facing upward.
This process assumes that the
wheel is hanging, so that the peak
vehicle Z axis is read 180° out of
phase (transducer peaks are the
weight of the wheel, in a
downward direction). The angle
determined is then shifted by
180°.
4
This is the
recommended
algorithm for spinning
Both the Angle Zero and Bridge Zero buttons are functional.
This algorithm will perform both angle zero and bridge zero
processes.
applications.
The Bridge Zero button is pressed when the Z beam is facing up.
You will need to
mechanically level the
SWIFT sensor
The Angle Zero button is pressed after the sensor is rotated 90° in
either the plus or minus direction.
The transducer is
unloaded during the
zero process.
(AngleMode=0)
Using the data collected from these two positions, all bridge zeros
and angle zeros are computed.
SWIFT 30 SensorsSetting up the Transducer Interface
63
Upload the Calibration File
Upload the Calibration File
A unique calibration file was loaded into the TI RAM by MTS before the
transducer and transducer interface were shipped. Use the program TIXFER to
retrieve the calibration file. TIXFER is a simple DOS-based program that will
prompt you for information.
1. Connect a communication cable from the laptop computer or PC to the TI.
2. Insert the SWIFT Transducer Interface Utilities diskette into the laptop
computer or PC.
3. Go to the DOS shell and run the program TIXFER.
When you type in the command to run the program, you must specify the
communications port for data transfer. For example, enter TIXFER 1 to
specify COM1.
4. Enter 1 at the prompt to upload the calibration file. (See the illustration
below.)
5. Enter the address for the TI box at the prompt.
The address for the TI is determined by the setting of the address selector
switch on the front panel. If you are using more than one transducer, each TI
will have a different address.
6. Enter a file name.
The file name must use the DOS naming convention (xxxxxxxx.xxx).
7. Enter a description of the file.
You may enter the serial number of the transducer or descriptive words to
help you identify the correct calibration file.
Setting up the Transducer Interface
64
SWIFT 30 Sensors
Upload the Calibration File
8. TIXFER will prompt you when the file has uploaded.
tixfer 1.7 beta ((10/25/04)
0...exit
1...Upload/Save a chassis
2...Restore/Download a chassis
Enter choice? 1
Enter TI box address? 1
Enter output specifications filename?
demo.cal
Enter description? demo upload
Allocating box...
Initializing box...
Uploading box...
Saving settings...
completed upload.
SWIFT 30 SensorsSetting up the Transducer Interface
65
Edit the Calibration File
CAUTION
Edit the Calibration File
Do not change any other items in the calibration file.
The calibration file contains offset values for all of the bridge outputs.
Changing any of the items other 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.
Setting up the Transducer Interface
66
SWIFT 30 Sensors
Edit the Calibration File
2. If necessary, edit the value for OutputPolarities.
This value sets the polarity states of all six outputs (Mz, My, Mx, Fz, Fy, and
Fx) using the following binary scheme (the default configuration is
represented):
O
UTPUTSMZMYMXFZFYFX
5
4
BIT
2
2
3222120
2
BIT VALUE
EXAMPLE
32168421
101000
= 4010
(default)
For example, if you want to invert Fx and Fy, and Mx and My, (making their
polarities opposite those shown on the labeling) you would make the
following changes:
M
ZMYMXFZFYFX
5
BIT
BIT VALUE
2
32168421
4
2
2322212
10 1000= 40
11 0011
* See the examples in the next table.
0
(old value)
10
= 5110 (new value)
*
SWIFT 30 SensorsSetting up the Transducer Interface
67
Edit the Calibration File
S20-34
Front
Fz
UpFyOut
Fx
Aft
Fz
Up
Fx
Fore
Fy
Out
S20-35
Front
Fy
In
Fz
Up
Fx
Aft
Fy
In
Fx
Fore
Fz
Up
S20-41
Front
Fx
Aft
Fy
In
Fz
Up
Fx
Aft
Fy
Out
Fz
Up
Output Polarity Value
Example Output Polarities
Description
Direction of Positive
output from load on tire
when mounted on left
hand side of the vehicle
Direction of Positive
output from load on tire
when mounted on right
hand side of the vehicle
OutputPolarities = 40Standard Setting from
MTS. Matches the axis
orientation on the front
cover of the SWIFT.
OutputPolarities = 51Common setting to
alter the axis for-aft and
in-out lateral axis
OutputPolarities (left side) = 51
OutputPolarities (right side) = 40
Common setting for
vehicle coordinate
matching between the
two sides of the
vehicle.
+Fx = fore
+Fy = out from car, left
+Fz = up
+Mx, +My+, +Mz =
Right-hand rule about
Force axis
+Fx = aft
+Fy= into car, right
+Fz = up
+Mx, +My, +Mz =
Right-hand rule about
Force axis
+Fx = aft
+Fy= into car, right
+Fz = up
+Mx, +My, +Mz =
Right-hand rule about
Force axis
+Fx = aft
+Fy = out from car, right
+Fz = up
+Mx, +My, +Mz = Righthand rule about Force
axis
+Fx = fore
+Fy = into car, left
+Fz = up
+Mx, +My, +Mz = Righthand rule about Force
axis
+Fx = aft
+Fy = out from car, right
+Fz = up
+Mx, +My, +Mz = Righthand rule about Force
axis
3. Perform this step for spinning application. For non-spinning applications,
skip to Step 4.
A. Edit the value for ZeroAlgorithm.
The zero algorithm value that you specify will affect the operation of
the Angle Zero and Bridge Zero switches.
Set ZeroAlgorithm=1, 3 or 4
1
B.Edit the value for AngleMode.
Set the AngleMode=0
In this mode, the encoder pulses are summed in with the offset and the
resulting value addresses the sine and cosine RAM, which perform the
rotational transformation of the output signals.
1. See the Zero Algorithms discussion on page 62 to help determine which
algorithm to use.
68
Setting up the Transducer Interface
SWIFT 30 Sensors
Edit the Calibration File
C.The AngleOffset value is used when you are operating in encoder
mode (spinning applications). This value is summed with the encoder
output count, and used to address the sine and cosine RAM when the
angle mode is set to 0 (encoder). Negative angles are converted to their
positive equivalent so that the readback value range is 0–360°.
The AngleOffset value is calculated by the TI during the zero process.
At the end of the process it is written to the calibration file.
There is no need to change this calculated value.
D. Edit the value for EncoderSize depending on the SWIFT Sensor being
used.
EncoderSize=0 (sensor with telemetry option–this option is not
available with the SWIFT 30 model)
EncoderSize=1 (sensor with slip ring option)
4. Perform this step for non-spinning applications. For spinning applications,
skip to Step 5.
A. Edit the value for ZeroAlgorithm.
The zero algorithm value that you specify will affect the operation of
the Angle Zero and Bridge Zero switches.
Set ZeroAlgorithm=0
B.Edit the value for AngleMode.
Set the AngleMode=1
In this mode, the sine and cosine RAM address is fixed. The encoder is
not used, nor is the encoder offset.
C.Edit the value for AngleFixed.
The AngleFixed value is used for non-spinning applications. This
value addresses the sine and cosine RAM when the angle mode is set to
1 (fixed). Negative angles are converted to their positive equivalent so
that the readback value range is 0–360°.
You may set the fixed angle value when you are operating in fixed
angle mode (non-spinning applications) only if the transducer is rotated
from its correct Fz–Fx orientation on the road simulator. For
installations where the Fz-Fx orientation on the SWIFT cover(s) is
aligned with gravity. The correct setting is:
AngleFixed=0
If the SWIFT is installed at an angle to the desired Fz–Fx output axis,
set the AngleFixed value equal to the installed angle offset in degrees,
with clockwise rotation positive.
For example: AngleFixed = 45.
5. Save the changes and exit the editor.
SWIFT 30 SensorsSetting up the Transducer Interface
69
Download the Calibration File
Download the Calibration File
Use the program TIXFER to download the modified calibration file to the TI.
1. Insert the diskette into the laptop computer or PC.
2. Go to a DOS shell and run the program TIXFER.
When you type in the command to run the program, you must specify the
communications port for data transfer. For example, enter TIXFER 1 to
specify COM1.
3. Enter 2 at the prompt to download the calibration file.
4. Enter the address for the TI box at the prompt.
The address for the TI is determined by the setting of the address selector
switch on the front panel. If you are using more than one transducer, each TI
will have a different address.
5. Enter the name of the file you wish to download.
The file must be in the same directory as the TIXFER program. The file
name must use the DOS naming convention (xxxxxxxx.xxx), which
means that you must type the full name and the extension.
6. TIXFER will prompt you when the file has successfully downloaded.
Setting up the Transducer Interface
70
SWIFT 30 Sensors
7. Enter 0 at the prompt to exit the program.
tixfer 1.7 beta ((10/25/04)
0...exit
1...Upload/Save a chassis
2...Restore/Download a chassis
Enter choice? 2
Enter TI box address? 1
Enter input specifications filename?
demo.cal
Allocating box...
Initializing box...
Restoring settings...
Downloading box...
Completed download.
tixfer 1.7 beta ((10/25/04)
Download the Calibration File
0...exit
1...Upload/Save a chassis
2...Restore/Download a chassis
Enter choice? 0
Program completed
SWIFT 30 SensorsSetting up the Transducer Interface
71
Download the Calibration File
Setting up the Transducer Interface
72
SWIFT 30 Sensors
Installing the Transducer
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.
ContentsTest Track Vehicle 74
Attaching SWIFT Components to the Vehicle 78
Installing the Transducer Interface Electronics 83
Setting up the SWIFT Sensor for Data Collection 85
Verifying the Quality of the Zero Procedure 95
Collecting Data 97
Road Simulator 99
Attaching SWIFT Components to the Fixturing 101
Zeroing the Transducer Interface 104
Communication Configurations 105
Cable Configurations 106
SWIFT 30 SensorsInstalling the Transducer
73
Test Track Vehicle
Test Track Vehicle
Equipment requiredThis procedure requires one person. To install the SWIFT 30A or SWIFT 30T
•Small set of hex-head wrenches (both English and metric)
•Tube bender for the anti-rotate bar
•Tube cutter
•Metric socket head drive set (up to 14 mm) with extension
•5/16-18 UNC tap
•Molykote g-n paste (MTS part number 011-010-207)
•Bolts
For SWIFT 30A Transducer
48 size M10 X 1.5 mm
4 size M8 X 1.25 mm
8 size M5 X 0.8 mm
lug nuts
For SWIFT 30T Transducer
48 size M10 X 1.5 mm
4 size M8 X 1.25 mm
8 size M5 X 0.8 mm
Lug nuts
•Torque wrenches, capable of the following ranges:
28–54 N•m (20–40 lbf•ft),
81–136 N•m (60-100 lbf•ft);
7 N•m (60 lbf •in)
Installing the Transducer
74
•Cables (transducer and BNC, plus customer-supplied from transducer
interface to data recorder)
•Tie wraps
•Data recorder
•12 V power supply (for example, a car battery)
SWIFT 30 Sensors
Test Track Vehicle
S20-03
Transducer
Hub Adapter
Slip Ring
(with Encoder)
Modified
Wheel Rim
Slip Ring
Bracket
(Spider)
CAUTION
Installation Components (Test Track)
Importance of boltsBolts provide exceptional clamp force at the transducer to rim/spindle interface.
•Bolts on the inner hub secure the hub adapter to the SWIFT sensor.
Before you beginObserve the following safety conditions while you are attaching the SWIFT
•Bolts on the outer ring secure the SWIFT sensor to the wheel rim (or road
simulator spindle adapter).
NoteMake sure all bolts are in place and fully torqued during all tests.
Correct use of bolts reduces the safety hazard and ensures optimal
transducer performance.
sensor and components to the vehicle.
Do not pressure-wash the transducer or clean it with solvents that would
degrade its silastic seal.
Pressure-washing the transducer or cleaning it with certain solvents can
damage it or degrade its silastic seal.
Avoid pressure-washing the transducer. Use only solvents that will not degrade
the silastic seal.
SWIFT 30 SensorsInstalling the Transducer
75
Test Track Vehicle
CAUTION
CAUTION
CAUTION
CAUTION
Do not use high-pressure-air to clean debris from around the transducer
connectors.
High-pressure-air can damage the silastic seals.
Use a fine wire brush and low air-pressure [0.07 MPa (10 psi)] to clean debris
from around the transducer connectors.
Do not lay the wheel flat while the transducer is attached to it.
When the wheel is laid flat with the transducer facing down the weight of the
wheel can damage the connectors.
Always hold the wheel upright when the transducer is attached to it. If needed,
have another person hold the tire upright while you tighten the bolts, or place the
wheel on a thin layer of foam to protect the connectors.
Do not under-torque the lug nuts.
Lug nuts that are not properly tightened can become loose during testing.
Loss of a wheel can cause damage to the test vehicle and transducer and
result in injury to personnel.
Always tighten the lug nuts to the torque rating recommended for the vehicle/
wheel.
Do not drop the slip ring bracket (spider).
Dropping the slip ring bracket can damage the slip ring or a connector.
Always use care when you handle the slip ring bracket.
Installing the Transducer
76
SWIFT 30 Sensors
Test Track Vehicle
CAUTION
Do not allow the mounting arm or anti-rotate arm to bump against any
portion of the wheel or wheel well.
The anti-rotate device should not bump against the wheel well or other
vehicle parts at any time. Any jarring of the anti-rotate arm will damage the
slip ring and/or the encoder.
Position the mounting arm and anti-rotate assembly so that full suspension travel
will not cause interference with the wheel well or any other part of the vehicle.
SWIFT 30 SensorsInstalling the Transducer
77
Test Track Vehicle
Attaching SWIFT Components to the Vehicle
SWIFT 30 Fasteners
M10 X 1.5 mm
M8 X 1.25 mm
M5 X 0.8 mm
MTS modified M12 X 1.5 mm
or 1/2–20UNF inch lug nuts
* For threaded spindle applications, customer
supplied M12 or 1/2 in fasteners of
appropriate length and thread pitch are
required.
*
Procedure1. Remove the current wheel from the test vehicle.
2. Clean all surfaces of the vehicle tire(s) and the modified rim(s). It is critical
that all surfaces be free of stones, burrs, and grease. Use a mild detergent
such as dish soap.
ImportantIt is imperative that the mounting surfaces of the transducer be
protected from getting scratched. Any wheel components and work
surfaces that might come in contact with the transducer must be
clean, smooth, and free of debris
Mount the tire(s) on the modified rim(s).
3. Wipe the unpainted mating surfaces of the modified rim and the transducer
with a clean dry cloth.
4. Attach the transducer to the modified wheel rim. Hand tighten the bolts.
If environmental conditions warrant, coat each fastener with Birchwood
Casey Sheath RB1 rust preventative (or equivalent).
Installing the Transducer
78
Lubricate the threads and under the heads of all fasteners, using Molykote
g-n paste.
SWIFT 30 Sensors
Test Track Vehicle
SWIFT 30A or SWIFT 30T
Viewed from Pilot Side
S30-16
Inner Bolt Pattern
Bolts AD are M8
Bolts 124 are M10
Outer Bolt Pattern
All bolts are M10
B
A
8
4
16
11
19
23
14
2
D
6
10
18
22
15
3
7
12
20
24
13
21
17
9
5
C
1
4
16
21
17
9
5
1
13
24
20
12
7
3
15
22
18
10
6
2
14
23
19
11
8
5. Attach the hub adapter to the transducer. Hand tighten the bolts.
If environmental conditions warrant, coat each fastener with Birchwood
Casey Sheath RB1 rust preventative (or equivalent).
Lubricate the threads and under the heads of all fasteners, using Molykote
g-n paste.
A clearance of approximately 0.05 mm (0.002 in) is required between the
transducer and the hub adapter. You should not have to wedge the wheel into
the rim or the hub adapter into the SWIFT sensor.
Bolt Torque Sequence
6. Tighten the mounting bolts.
A. Following the sequence shown in the previous figure for the transducer
ImportantThe M8 bolts in the inner bolt pattern (bolts A–D in the previous
being installed, torque the four M8 inner hub bolts in two increments as
shown in the following table.
figure) must be torqued, as described, before torquing the M10
bolts.
B.Following the sequence shown in the previous figure for the transducer
being installed, torque the twenty-four M10 inner hub bolts in two
increments as shown in the following table.
SWIFT 30 SensorsInstalling the Transducer
79
Test Track Vehicle
NoteTo minimize negative clamping effects, you must torque the bolts in the
sequence shown.
B
OLT SIZE
TORQUE INCREMENTM8M10
1st Increment
Final Torque
14 N•m (10 lbf•ft)27 N•m (20 lbf•ft)
27 N•m (20 lbf•ft)54 N•m (40 lbf•ft)
C.Following the sequence shown in the previous figure for the transducer
being installed, torque the twenty-four M10 outer hub bolts in two
increments as shown in the previous table. See the previous note.
Installing the Transducer
80
SWIFT 30 Sensors
Attaching SWIFT and Wheel Assembly to the Vehicle
1. Before installing the SWIFT and wheel assembly, attach the slip ring antirotate bracket to the vehicle.
Since the bracket is unique to each vehicle the slip ring anti-rotate bracket
must be provided by the customer. The following are guidelines for
manufacturing and locating the bracket. See the next figure.
•The bracket must be stiff, preferably steel or stiff aluminum tubing, so
as not to move or rotate when connected to an unsprung mass or
spindle which will allow the slip ring assembly to move with the tire as
the vehicle is moving or testing.
•The bracket must be positioned so as not to hit the fender at the
extreme end of the suspension travel.
•The bracket must maintain a minimum clearance from the tire so as not
to hit the tire when it is loaded and rotating.
2. Attach the wheel/transducer to the test vehicle.
Test Track Vehicle
Lubricate the lug bolt threads with Molykote g-n paste.
Tighten the lug nuts to the torque rating recommended for the wheel.
3. Attach the slip ring bracket (spider) and slip ring to the transducer.
A. The slip-ring bracket fits over the 10-pin connectors on the front of the
transducer at the locations labeled Board A and Board B. The slip-ring
bracket is similarly labeled to prevent connecting it the wrong way.
NoteUse care when installing the slip-ring bracket. The 10-pin connectors are
keyed. The slip-ring bracket should be fitted on straight (without bending
or angling it) to make sure it engages both connectors simultaneously
and evenly.
B.Lubricate the threads and under the bolt heads of the eight M5 X 0.8
mm bolts with Molykote g-n paste. Insert them through the mounting
hole in the slip ring bracket and thread them into the transducer. Torque
them to 6.8 N•m (60 lbf•in).
C.Make sure that the covers on the shunt connectors are securely locked
in place. Each cover should be twisted until it snaps into the retaining
groove.
4. Attach the anti-rotate assembly to the anti-rotate bracket (installed earlier)
and the slip ring. If this is the first time the anti-rotate assembly is used on
this vehicle or if the mounting location has changed, perform Steps A and B,
otherwise proceed to Step C. (Refer to the next figure for guidelines.)
A. Weld the steel tube sleeve to the customer-supplied customer supplied
anti-rotate bracket.
B.Bend the aluminum tube to fit over the wheel.
SWIFT 30 SensorsInstalling the Transducer
81
Test Track Vehicle
Slip Ring
Assembly
Suspension/
Unsprung Mass
Minimum Clearance
Typically approximately
6 mm (0.25 in) depending
on tire uniformity. Tire
must not hit bracket when
loaded or rotating.
Anti-Rotate Bracket
must be Stiff (preferably steel
or stiff aluminum tubing), so as
not to move or rotate when
connected to unsprung mass
or spindle, which will allow the
slip ring assembly to move with
the tire as the vehicle is
moving or testing.
Center line
of Wheel
Anti-Rotate
Assembly
Transducer
5/16-18 UNC
Low-head Socket Screw
19 mm (0.75 in) long
Steel
Sleeve
Modified Delrin Ball
15.875 mm (0.625 in)
diameter
Vehicle
Fender
Bracket must not hit
fender at extreme end
of suspension travel
Weld steel sleeve to
anti-rotate bracket
when assembly is
mounted on vehicle
S30-18
M4 X 0.7 mm
X10 mm long
or 8-32 X 3/8 in long
Socket Head
Cap Screw (qty 2)
Transducer
Output Cable
C.Measure, making bends as necessary, and cut the aluminum tube to
size.
MTS provides an extra long tube with a hinge welded at one end. After
fitting the tube to your test vehicle, cut off the excess length.
D. Tap the end of the aluminum tube 5/16-18 UNC X 1.00 inch deep.
E.Insert the low-head cap screw through the delrin ball.
F.Insert the aluminum tube into the steel sleeve.
G.Tighten the screws that attach the hinge joint to the slip ring assembly.
82
Installing the Transducer
5. Attach the transducer output cable to the slip ring encoder connector and the
Slip Ring D-connector on the rear of the TI.
6. Secure the cable along its length so that ot will not become damaged during
data collection. (For example, tape it to the external mirror.)
Be sure to leave enough slack in the cable to allow for the full range of
wheel travel (jounce and steer).
SWIFT 30 Sensors
Installing the Transducer Interface Electronics
The Transducer Interface (TI) electronics should be securely fastened to the
vehicle in a protected location. The TI box is designed to withstand the
accelerations associated with the body of a vehicle during rugged durability and
typical data acquisition testing.
The TI box can be located anywhere in the vehicle that is convenient. However,
if the TI is able to bounce around during data collection, it can bump against
another piece of equipment, pushing in the Zero button. If the Zero button is
pushed, you will lose all of the data.
ConsiderationsSuitable locations for the TI box include the vehicle trunk, flatbed, interior floor,
or rear seat. Consider the following guidelines when you fasten the TI box(es) to
the vehicle:
•Mount the TI box in a position on or in the vehicle that is protected from
impact and high acceleration events.
•Do not expose the TI box to rain, snow, or other wet conditions.
Test Track Vehicle
•Orient the TI box horizontally.
•Multiple TI boxes may be rigidly attached to each other using optional
mounting straps.
•Place a thin foam or rubber material between TI boxes and any hard
mounting surface.
•Use ratcheting straps to provide a tight connection that will not loosen or
untie during testing.
•Do not use rubber cords to secure the TI box because they may stretch and
lose retention in the cord due to inertial forces.
Procedure1. Connect all data cables from the TI to the data recorder.
There is one cable per channel of data from the TI to the data recorder.
These correspond to the three forces, three moments, and angular position.
NoteMake 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 and the data recorder to a 12 V DC power source (such as a
vehicle battery).
NoteSome 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.
SWIFT 30 SensorsInstalling the Transducer
83
Test Track Vehicle
Ground to
vehicle frame
12 Vdc
Transducer Interface
S50-025
Data Recorder
Ground to
vehicle frame
12 Vdc
Transducer Interface
Transducer Interface
Transducer Interface
Transducer Interface
S50-026
Data Recorder
3. Ground the TI and data recorder to the vehicle frame. (See the following
figures.)
Suggested Grounding for a single TI Box
Installing the Transducer
84
Suggested Grounding for a Multiple TI Boxes
4. Secure the TI box so that it will not move during data collection.
NoteIf the TI box is not properly secured, it can bump against another piece of
equipment or a hard surface, pushing in the Zero button. If the Zero
button is pushed, you will lose all of the data.
5. Verify that the shunt contacts are covered.
Make sure that the plugs on the slip ring bracket (spider) cover are in place
so that no water will enter the contacts.
Make sure that the bayonette covers on the shunt connectors are securely
locked in place. Each cover should be twisted until it snaps into the retaining
groove.
6. Turn on the TI and let it warm up for 15-20 minutes before you zero the
SWIFT 30 Sensors
strain gage bridges.
Setting up the SWIFT Sensor for Data Collection
CAUTION
CAUTION
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 introduce extraneous forces or excessive accelerations into the
wheel while rotating it during the Zero process.
Test Track Vehicle
Considerations for
rotating a tire
Any forces applied to the wheel, tire, rim, spider, or outer portion of the
transducer will cause a Bridge Zero error.
Make sure to apply only a gentle force at a steady rate to the inner hub while
rotating it.
Do not touch or bump the wheel while the transducer is zeroing.
Touching or bumping the wheel will add loads to the transducer, resulting in
an erroneous zero reading.
Avoid all contact with the wheel while the transducer is zeroing. If you suspect that
the zero process is incorrect, begin again
When using a zero method that collects zero data while the sensor is rotating (i.e.,
algorithm 1 or 3), you must be careful to minimize the forces that are induced in
the transducer’s bridges.
When using one of these zero methods, never rotate the tire directly, or by
grabbing the outer diameter of the transducer. This will introduce forces into the
transducer bridges that will result in a bad zero process and unreliable data.
•Rotate the tire at an even rate to avoid accelerations on the transducer.
•For positive-lock differentials, turn the other tire on the axle to cause the
desired rotation in the transducer you are zeroing.
•If you must touch the transducer to rotate the tire, carefully rotate the tire by
touching only the inner diameter of the transducer.
SWIFT 30 SensorsInstalling the Transducer
85
Test Track Vehicle
Choosing a Zero
method
Preferred method—Zero Algorithm 4 is the preferred method for configuring
the calibration file for spinning applications:
ZeroAlgorithm=4
AngleMode=0
This zero method samples all eight input bridges at two positions. After the data
is taken, all eight input channels are analyzed for signal offsets, and bridge zeroes
and angle zeroes are set in the TI.
Alternate methods—Zero Algorithm 1 and 3 are alternate methods for
configuring the calibration file:
ZeroAlgorithm=1
AngleMode=0
Zero Algorithm 1 samples all eight input bridges on every encoder tick, for one
complete revolution. After the data is taken, all eight input channels are analyzed
for signal offsets, and bridge zeroes are set in the TI. The angle offset is then
recorded in a separate step.
ZeroAlgorithm=3
AngleMode=0
Zero Algorithm 3 may be more convenient for some test setups. However, you
must take care when using it, because it is susceptible to two types of errors:
•Noise spikes from power. These can be minimized by following the
grounding suggestions illustrated earlier in this chapter.
•Extraneous loads. Be very careful to rotate the wheel only by touching the
inner hub of the transducer or by engaging the axle (for some vehicles, this
means putting the vehicle in Park) and rotating the opposite wheel.
Because the SWIFT sensor measures loads applied to the outer edge of the
transducer, you should never touch the outer edge while you are spinning
the wheel. The rotation speed should be smooth, in order to avoid applying
inertial braking moments to the transducer.
0 Non-spinning mode
1 Spinning mode (uses a digital
inclinometer for angle zero and
spinning the tire for the bridge zero
process
2 Not used
3 Spinning mode (uses spinning the
tire for both angle and bridge
processes)
4 Spinning mode (use a digital
inclinometer to define two positions
90° apart for the bridge zero and
angle zero processes.
Angle Mode
0 Spinning mode (obtains angle from
the encoder)
1 Fixed angle mode (used for test rigs
in the lab)
This zero method samples all eight input bridges on every encoder tick, for one
complete revolution. After the data is taken, all eight input channels are analyzed
for signal offsets, and the X and Z input channels are analyzed to determine the
angular zero point.
SWIFT 30 SensorsInstalling the Transducer
Example of a .cal file
If Zero Algorithm=4When you zero the TI, you want the vehicle to be fairly level and the transducer
to be as close to plumb as practical.
1. Install the SWIFT sensor(s) and data collection equipment on the vehicle.
2. Connect all cables and turn on the power to the TI boxes.
3. Let the TI boxes and transducers warm up for 15-20 minutes.
4. Run the TISTATUS program to compare the supply voltages to the
5. Verify that the calibration file is set up correctly for your testing application.
reference voltages.
Type: TIstatus <port#> <box#>
If the supply voltages vary more than 0.5 V from the reference voltages,
there is a power supply problem that must be resolved before you can
continue.
87
Test Track Vehicle
Axes Icon
S20-22
A. Download the spinning calibration file (xxxxxs.cal) to the computer
from the MTS Disk that corresponds to the serial number of the
transducer that you are setting up.
B.If necessary, modify the zero algorithm and angle mode to fit the
application/use requirements as described in, “Edit the Calibration
File,” on page 66.
C.The EncoderSize parameter should be omitted or set to EncoderSize=1
D. Download the calibration file to the TI box.
NoteIf it becomes necessary to change the zero algorithm or angle mode
after downloading the file to the TI, you can do so by using the
TISETZERO utility, as described in, “TISETZERO – Transducer Interface
Set Zero Method,” on page 55.
6. Elevate the vehicle with a lift, raise each corner with a jack.
7. Perform the zero procedure on each corner of the vehicle.
Use a digital inclinometer to zero the angle and strain gage bridges on the
transducer.
A. Rotate the tire one full revolution so that the encoder can find the zero
index mark.
NoteThe encoder has a red dot on the mounting flange connected to the slip-
ring bracket and a black dot on the slip-ring connector housing where it
interfaces with the mounting flange. These dots, when aligned next to
each other, indicate the index mark is under the encoder sensor.
B.Rotate the tire as necessary, until the Fz on the axes icon (see the next
figure) printed on the transducer label is pointing up
C.Attach the level bracket so that it sits on top of the transducer. Insert the
locking pin through the bracket and into the pin pilot hole on the
transducer (see the next figure).
Installing the Transducer
88
SWIFT 30 Sensors
Test Track Vehicle
Digital Inclinometer
in this position
should read 0°, ±0.1°
Axes Icon
Insert Lock Pin
in Pilot Hole
Level Bracket
S30-20
Digital Inclinometer
(alternate location)
in this position
should read 90°, ±0.1°
S20-21
Angle Zero
Switch and Indicator
Bridge Zero
Switch and Indicator
NoteIf the anti-rotate assembly interferes with the mounting of the digital
inclinometer, use the alternate mounting location shown.
D. Place the digital inclinometer on the bracket and rotate the tire until the
inclinometer reads 0.0°, ±0.1° (or 90.0°, ±0.1° if the alternate position
is used).
E.Push the Bridge Zero button on the front of the TI box. The LED will
turn on for a few seconds, then start blinking rapidly. The Angle Zero
indicator will start blinking slowly.
F.Remove the digital inclinometer and level bracket.
G.Rotate the tire 90° in either direction.
H. Attach the level bracket in the same orientation as in Step 7C.
Insert the locking pin through the bracket and into the pin pilot hole on
the transducer.
SWIFT 30 SensorsInstalling the Transducer
89
Test Track Vehicle
Digital Inclinometer
in this position
should read 0°, ±0.1°
Insert Lock Pin
in Pilot Hole
Level Bracket
S30-23
Rotate Transducer
+ or - 90°
Digital Inclinometer
(alternate location)
in this position
should read 90°, ±0.1°
I.Place the digital inclinometer on the bracket and rotate the tire until the
inclinometer reads 0.0°, ±0.1° (or 90.0°, ±0.1° if the alternate position
is used).
J.Push the Angle Zero button on the front of the TI box. The Angle Zero
indicator will light for a few seconds, then both the Bridge Zero and
Angle Zero indicators should turn off.
NoteIf the red Fail indicator lights momentarily and the Bridge Zero and
Angle Zero indicators end up blinking slowly, problems were detected
with the zero. Try repeating the procedure. Use TISTATUS for a more
detailed explanation of the problem. If you continue to have an error,
consult the chapter, “Troubleshooting,” on page 127.
K. Rotate the transducer slightly to update the rotational transformation.
At this point the TI should be reading absolute forces in the vehicle
coordinate system.
L.Perform, “Verifying the Quality of the Zero Procedure,” on page 95.
M. Look at your data acquisition system to verify that the SWIFT sensor is
If Zero Algorithm=1When you zero the TI, you want the vehicle to be fairly level and the transducer
to be as close to plumb as practical.
1. Install the SWIFT sensor(s) and data collection equipment on the vehicle.
2. Connect all cables and turn on the power to the TI boxes.
gathering data.
3. Let the TI boxes and transducers warm up for 15-20 minutes.
Installing the Transducer
90
SWIFT 30 Sensors
Test Track Vehicle
4. Run the TISTATUS program to compare the supply voltages to the
reference voltages.
Type: TIstatus <port#> <box#>
If the supply voltages vary more than 0.5 V from the reference voltages,
there is a power supply problem that must be resolved before you can
continue.
5. Verify that the calibration file is set up correctly for your testing application.
A. Download the spinning calibration file (xxxxxs.cal) to the computer
from the MTS Disk that corresponds to the serial number of the
transducer that you are setting up.
B.If necessary, modify the zero algorithm and angle mode to fit the
application/use requirements as described in, “Edit the Calibration
File,” on page 66.
C.The EncoderSize parameter should be omitted or set to EncoderSize=1
D. Download the calibration file to the TI box.
NoteIf it becomes necessary to change the zero algorithm or angle mode
after downloading the file to the TI, you can do so by using the
TISETZERO utility, as described in, “TISETZERO – Transducer Interface
Set Zero Method,” on page 55.
6. Put the vehicle on a lift or jack up the corner of the vehicle on which the
SWIFT sensor is mounted.
ImportantPlace wheel chocks under the wheels on the ground or otherwise
restrain the vehicle to prevent it from moving.
7. Push the Bridge Zero button. Only the Bridge Zero indicator will light.
8. Gently spin by hand, the wheel on the opposite side of the vehicle for two
revolutions. Be careful not to allow the wheel to stop or reverse direction.
This will cause the wheel you are zeroing to spin without load.
NoteFor rear wheels or wheels where this cannot be done, carefully spin the
wheel to be zeroed by gently contacting only the hub adapter bolted to
the SWIFT sensor.
9. Stop spinning the wheel when the Bridge Zero indicator begins to blink at a
rate of 4 Hz and continues blinking for about one minute.
The Bridge Zero indicator will then turn off, indicating completion of the
Bridge Zero procedure.
10. Perform the Angle Zero procedure.
Use a digital inclinometer to zero the angle on the transducer, then rotate the
tire to zero the strain gage bridges.
A. Rotate the tire one full revolution so that the encoder will pass the zero
index mark at least once.
SWIFT 30 SensorsInstalling the Transducer
91
Test Track Vehicle
Axes Icon
S20-22
Digital Inclinometer
in this position
should read 0°, ±0.1°
Axes Icon
Insert Lock Pin
in Pilot Hole
Level Bracket
S30-20
Digital Inclinometer
(alternate location)
in this position
should read 90°, ±0.1°
NoteThe encoder has a red dot on the mounting flange connected to the slip-
ring bracket and a black dot on the slip-ring connector housing where it
interfaces with the mounting flange. These dots, when aligned next to
each other, indicate the index mark is under the encoder sensor.
B.Rotate the tire as necessary, until the Fz on the axes icon (see the next
figure) printed on the transducer label is pointing up
C.Attach the level bracket so that it sits on top of the transducer. Insert the
locking pin through the bracket and into the pin pilot hole on the
transducer (see the next figure).
NoteIf the anti-rotate assembly interferes with the mounting of the digital
inclinometer, use the alternate mounting location shown.
Installing the Transducer
92
D. Place the digital inclinometer on the bracket and rotate the tire until the
inclinometer reads 0.0°, ±0.1° (or 90.0°, ±0.1° if the alternate position
is used).
E.Push the Angle Zero button on the front of the TI box. The Angle Zero
indicator will turn on for a few seconds, then turn off indicating that the
Angle Zero procedure is complete.
11. After completing the Bridge and Angle Zero procedures, rotate the wheel
one full revolution clockwise.
This allows the electronics to locate the index pulse for the encoder.
SWIFT 30 Sensors
Test Track Vehicle
NoteThe wheel must rotate one-half revolution in the same direction and then
pass over the encoder index point before data collection is started.
12. Perform, “Verifying the Quality of the Zero Procedure,” on page 95.
13. Look at your data acquisition system to verify that the SWIFT sensor is
gathering data.
If Zero Algorithm=3When you zero the TI, you want the vehicle to be fairly level and the transducer
to be as close to plumb as practical.
1. Install the SWIFT sensor(s) and data collection equipment on the vehicle.
2. Connect all cables and turn on the power to the TI boxes.
3. Let the TI boxes and transducers warm up for 15–20 minutes.
4. Run the TISTATUS program to compare the supply voltages to the
reference voltages.
Type: TIstatus <port#> <box#>
If the supply voltages vary more than 0.5 V from the reference voltages,
there is a power supply problem that must be resolved before you can
continue.
5. Verify that the calibration file is set up correctly.
A. Download the calibration file (xxxxx.cal) to the computer from the
MTS Disk that corresponds to the serial number of the transducer that
you are setting up.
B.If necessary, modify the zero algorithm and angle mode to fit the
application/use requirements as described in, “Edit the Calibration
File,” on page 66.
C.The EncoderSize parameter should be omitted or set to EncoderSize=1
D. Download the calibration file to the TI box.
NoteIf it becomes necessary to change the zero algorithm or angle mode
after downloading the file to the TI, you can do so by using the
TISETZERO utility, as described in, “TISETZERO – Transducer Interface
Set Zero Method,” on page 55.
6. Elevate the vehicle with a lift, or raise each corner with a jack.
7. Perform the zero procedure on each corner of the vehicle. Both the angle
and bridge zeros are computed by rotating the tire.
SWIFT 30 SensorsInstalling the Transducer
93
Test Track Vehicle
S20-21
Angle Zero
Switch and Indicator
Bridge Zero
Switch and Indicator
A. Push either the Angle Zero or Bridge Zero button on the front of the
TI box. Both indicators will light.
B.Rotate the tire 1 1/4 to 2 revolutions, until the Bridge Zero indicator
starts flashing. Follow the guidelines in, “Considerations for rotating a
tire,” on page 85.
C.If the Bridge Zero indicator continues to slowly flash after 2 minutes,
or if the red Fail indicator flashes, there is an error in the zero process.
Run TISTATUS to find out more information. Repeat Steps A and B. If
you continue to have an error, consult the chapter, “Troubleshooting,”
on page 127.
D. Perform, “Verifying the Quality of the Zero Procedure,” on page 95.
E.Look at your data acquisition system to verify that the SWIFT sensor is
gathering data.
Installing the Transducer
94
SWIFT 30 Sensors
Verifying the Quality of the Zero Procedure
Connect to
Data Acquisition
System
Shunt A
Board A
Board A
Shunt B
S30-24
Perform the following consistency checks for each SWIFT sensor while the
vehicle (or corner) is elevated.
1. Does Fz measure the approximate weight of the tire/rim assembly?
2. Is Fx small (less than 0.1% of the rated load)?
3. What is the variance in Fz (modulation) when the tire is slowly rotated?
4. When the vehicle is on the ground, is the Fz reading approximately equal to
the corner weight of the vehicle? (See, “Effect of Zero Reference on SWIFT
Output,” on page 96.)
Acceptable Variations for Fx, Fz Readings
T
RANSDUCER MODELMAX RATED LOAD
(F
X, FZ)
X READING
F
WITH VEHICLE LIFTED
Test Track Vehicle
FZ MODULATION
WITH VEHICLE LIFTED
SWIFT 30 A (Aluminum)
SWIFT 30T (Titanium)
28 kN0.1% (±20–30 N)0.2% (±40–60 N)
50 kN0.1% (±40–50 N)0.2% (±60–100 N)
5. Perform a Shunt calibration on each transducer.
A. Elevate the vehicle on a lift, or jack up each corner.
B.Connect the shunt calibration cables from the Shunt A, Shunt B
connectors on the front of the transducer to the Shunt A, Shunt B
connectors on the back of the TI box (see the next figure).
C.Connect the signal cable from the slip ring to the Slip Ring connector
on the back of the TI box.
D. Press the Shunt button on the front of the TI box, or use option 5 in the
TISHUNT program.
The shunt indicator will light continuously for 30–45 seconds. If the
indicator continues to flash after shunt calibration is complete, the
shunt calibration has failed.
Connect the shunt calibration cables
SWIFT 30 SensorsInstalling the Transducer
95
Test Track Vehicle
6. Verify that the outputs from the TI box matches those on the calibration
report.
Use either the TISHUNT or TIXFER program to look at the shunt values of
the individual bridges.
The shunt calibration will fail if the measured shunt values are >2% of the
reference values that were set at the factory. Typically, the shunt values will
vary a maximum of 0.20-0.30 V from the reference values.
Refer to the chapter, “Troubleshooting,” on page 127, for more information
on dealing with shunt calibration failures.
Effect of Zero
Reference on SWIFT
Output
When the SWIFT sensor is used in spinning applications, it is important that a
correct absolute zero of each strain gage bridge is used to ensure the proper
computation and transformation of the transducer outputs to a non-rotating
vehicle coordinate system. An error in the absolute zero of each bridge will
produce a one-time-per-revolution modulation error in the output signals. To
achieve absolute zero of each bridge, the zeroing process must account for the
tare weight acting on the transducer.
When the vehicle is lifted and the tire and wheel assembly are suspended, the
mass of the tire, rim, outer diameter fasteners, and outer ring of the transducer are
all reacted through the beams of the transducer. With gravity acting on this outer
tire/rim assembly, the SWIFT sensor measures a vertical force pulling down on
the transducer.
The SWIFT output cannot be zero, because it is not possible to set the vehicle on
the ground precisely enough that the ground supports only the outer tire/rim
weight.
As the vehicle is set completely on the ground, the output from the SWIFT sensor
will read the corner weight of the vehicle from the reference point of the
transducer. The output of the SWIFT sensor will be slightly less than the total
corner weight of the vehicle, because the SWIFT sensor is inboard of the outer
tire and rim assembly, and will therefore not measure the weight of the outer tire
and rim assembly.
Installing the Transducer
96
SWIFT 30 Sensors
Collecting Data
Test Track Vehicle
After you zero the TI, you are ready to collect data.
NoteIf you turn off power to the TI boxes, the zero values will remain valid, but
the encoder will need to find the index pulse to properly convert the
rotating coordinates to stationary coordinates. The transducer outputs
will not be correct until this happens.
To reset the encoder, roll the vehicle either forward or backward so that
the tire completes at least one revolution. This can be accomplished
while driving to the test area, or if the vehicle is on a lift in the garage
area, rotate the tire according to the guidelines in , “Considerations for
rotating a tire,” on page 85.
1. Spin the wheel twice to ensure that the encoder tick is correct.
Spinning the wheel after you have completed the zero process will ensure
that the encoder is correctly referenced to the index pulse. Otherwise, the
data collected during the first revolution will be flawed.
2. Remove the vehicle from the lift or jacks.
3. Secure the connector that attaches the signal cable to the top of the slip ring
with high quality duct or electrical tape.
This will prevent dust, dirt, and water from entering the connector and
causing wear on the pins and sockets.
4. Verify that the shunt contacts are covered.
Ensure that the plugs on the slip ring bracket (spider) cover are in place so
that no water will enter the contacts.
Ensure that the covers on the shunt connectors are securely locked in place.
Each cover should be twisted until it snaps into the retaining groove.
5. Perform a final inspection of the SWIFT sensor and the electronics to ensure
that everything is secure and the TI is on.
The zero data is saved at the end of each completed procedure. If the TI is
off, the zero data will not be lost. However, due to thermal conditions that
could affect your data, if the TI is powered off for an extended period of
time (such as over night), you must repeat the zero process.
NoteRezeroing the transducer is good practice when thermal changes occur.
Rezeroing the transducer at conditions and temperatures closest to the
test conditions will provide a more accurate zero and reduce thermal
errors.
6. Turn on the data recorder.
7. Start data collection.
ImportantBefore beginning data collection, read the cautions on the next
page.
SWIFT 30 SensorsInstalling the Transducer
97
Test Track Vehicle
CAUTION
CAUTION
WARNING
WARNING
Do not allow the SWIFT assembly to bump into any hard surfaces while you
are driving the vehicle.
Bumping the SWIFT assembly into hard surfaces such as garage doors,
ramps and railings will damage the anti-rotate device, cable, slip ring, slip
ring bracket (spider), and transducer.
The SWIFT assembly will protrude approximately four inches (102 mm) from the
side of the vehicle. Remember to allow extra space on each side of the test
vehicle as you enter and exit areas with possible hazards.
Do not drive through tall grass and brush.
Driving through tall grass and brush can damage the cable and tear off the
slip ring.
Avoid areas of the test track with tall grass and brush.
Do not use the SWIFT sensor on public roads.
Public use or use on public roads could endanger the public.
Use the SWIFT sensor only on closed courses where the loads and load cycles
are recorded and managed within the prescribed limits. Only experienced test
vehicle drivers should operate a vehicle with the SWIFT sensor attached
Do not use the SWIFT sensor after excessive loading or load cycles.
The SWIFT sensor has a limited load life. Excessive loading or load cycles
could cause a fracture of the transducer, wheel rim, hub adapter, or
fasteners and can result in injury or death.
Always be aware of the maximum full scale loads appropriate for your transducer.
Upon approaching a prescribed limit, return the transducer with the recorded load
cycles to MTS for physical inspection and analysis of the load cycle history
Installing the Transducer
98
SWIFT 30 Sensors
Road Simulator
CAUTION
CAUTION
CAUTION
Before you beginAngular correction is required on the test track only. If you are using the same
transducer(s) for non-spinning simulation testing you must load the correct
software into the TI.
The SWIFT sensor must be attached to the test fixture before the vehicle is
mounted.
Clean all surfaces. It is critical that all surfaces be free of stones, burrs, and
grease.
Do not pressure-wash the transducer or clean it with solvents that would
degrade its silastic seal.
Pressure-washing the transducer or cleaning it with certain solvents can
damage it or degrade its silastic seal.
Road Simulator
Avoid pressure-washing the transducer. Use only solvents that will not degrade
the silastic seal.
Do not use high-pressure-air to clean debris from around the transducer
connectors.
High-pressure-air can damage the silastic seals.
Use a fine wire brush and low air-pressure [0.07 MPa (10 psi)] to clean debris
from around the transducer connectors.
Do not under-torque the lug nuts.
Lug nuts that are not properly tightened can become loose during testing.
Loss of a wheel can cause damage to the test vehicle and transducer and
result in injury to personnel.
Always tighten the lug nuts to the torque rating recommended for the vehicle/
wheel.
SWIFT 30 SensorsInstalling the Transducer
99
Road Simulator
Equipment requiredThis procedure requires one person. To install the transducer, you will need the
following equipment:
•Hub adapter
•Modified rim
•Spindle housing adapter plate
•Connector housing
•Locating pins
•Small set of hex-head wrenches (both English and metric)
•Metric socket head drive set (up to 14 mm) with extension
•Molykote g-n paste (MTS part number 011-010-207)
•Bolts
For SWIFT 30A Transducer
48 size M10 X 1.5 mm
4 size M8 X 1.25 mm
8 size M5 X 0.8 mm
lug nuts
For SWIFT 30T Transducer
48 size M10 X 1.5 mm
4 size M8 X 1.25 mm
8 size M5 X 0.8 mm
Lug nuts
•Torque wrenches, capable of the following ranges:
28–54 N•m (20–40 lbf•ft),
81–136 N•m (60-100 lbf•ft);
7 N•m (60 lbf •in)
•Cables (transducer and BNC, plus customer-supplied from transducer
interface to data recorder)
•Tie wraps
Installing the Transducer
100
•Data recorder
•12 V power supply (for example, a car battery)
SWIFT 30 Sensors
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