Interface T8 User manual

T8 Torque Sensor Operation Manual
Interface Inc. ● 7401 East Butherus Drive, Scottsdale, Arizona 85260 USA ● Phone [phone] ● Fax [phone]
www.interfaceforce.com ● Email: [e-mail] ● 800.947.5598
Page 1 of 11
T8 Torque Sensor Operation Manual

T8 Torque Sensor Operation Manual
Interface Inc. ● 7401 East Butherus Drive, Scottsdale, Arizona 85260 USA ● Phone [phone] ● Fax [phone]
www.interfaceforce.com ● Email: [e-mail] ● 800.947.5598
Page 2 of 11
Imprint
Valid for... Torque sensor type T8
Reprint Interdiction Reprints, even in extracts, only with written authority.
Modification Technical changes reserved.
References in this Text
Warning Notes, Page 4
Attention must be paid to the accident prevention regulations of the trade associations. Coverings
and casings are necessary before operating the sensor. This is also valid for commissioning,
maintenance and trouble shooting.
Duties of the coverings and casings are:
฀ Protection from detaching parts
฀ Protection from contusion and shear
฀ Prevention from reaching rotating parts
฀ Prevention from being tangled up and/or getting caught by parts Coverings may
฀ Not grind
฀ Not rotate
Coverings are also necessary outside of operating and motion travel areas of persons. These
demands can be modified if other sufficient safety devices are available. During operation, the
safety precautions must be operative. By vibrations, damages can occur at the device.
Alignment of the Measurement Arrangement
For further references see coupling manual.
General
Before the assembly, shafts must be cleaned with dissolver (e.g. acetone); no foreign
particles may adhere to them. The hub must fit corresponding to the connection.
During the assembly, the sensor must be supported to protect it from falling down.
Caution: During the assembly inadmissibly large forces may not act on the sensor or the
couplings.
Torque Sensors below 20 N.m
Sensors with nominal torques below 20 N·m are very sensitive to overload, therefore these
sensors need to be handled with greatest caution.
Free-floating Assembly
In this installation case, double-jointed couplings cannot be used for both sides!
Risk of Breakage!
Engaging
Warming-up period of the torque sensor is approx. 5 min.
Natural Resonances
An operation of the device in natural resonance can lead to permanent damages.

T8 Torque Sensor Operation Manual
Interface Inc. ● 7401 East Butherus Drive, Scottsdale, Arizona 85260 USA ● Phone [phone] ● Fax [phone]
www.interfaceforce.com ● Email: [e-mail] ● 800.947.5598
Page 3 of 11
Contents
Table of Contents
Imprint .............................................................................................................................................................................. 2
Contents............................................................................................................................................................................ 3
1 Read First........................................................................................................................................................... 4
Safety and Caution Symbols...................................................................................................................................... 4
Intended Use............................................................................................................................................................. 4
Dangers
Neglecting of Safety Notes........................................................................................................................................ 4
Remaining Dangers ................................................................................................................................................... 4
Reconstructions and Modifications .......................................................................................................................... 4
Personnel .................................................................................................................................................................. 4
Warning Notes .......................................................................................................................................................... 4
2 Term Definitions ................................................................................................................................................ 5
Terms
Definition of the Pictograms on the Torque Sensor.................................................................................................. 5
3 Product Description .......................................................................................................................................... 5
Mechanical Setup...................................................................................................................................................... 5
Electrical Setup.......................................................................................................................................................... 6
4 Mechanical Assembly ........................................................................................................................................ 6
Couplings
Misalignment Possibilities of Single-Jointed Couplings............................................................................................. 6
Double-Jointed Couplings ......................................................................................................................................... 6
Alignment of the Measurement Arrangement ......................................................................................................... 6
General
Torque Sensors below 20 N·m.................................................................................................................................. 7
Torque Sensors from 20 N·m and above .................................................................................................................. 7
Free-floating Assembly.............................................................................................................................................. 7
Foot Version Assembly.............................................................................................................................................. 8
5 Electrical Connection......................................................................................................................................... 8
Pin Connection .......................................................................................................................................................... 8
Cable
Shielding Connection ................................................................................................................................................ 8
Running of Measuring Cables ................................................................................................................................... 8
6 Measuring ......................................................................................................................................................... 9
Engaging
Direction of Torque ................................................................................................................................................... 9
Static / Quasi-Static Torques..................................................................................................................................... 9
Dynamic Torques ...................................................................................................................................................... 9
General
Natural Resonances .................................................................................................................................................. 9
Speed Limits .............................................................................................................................................................. 9
Disturbance Variables ............................................................................................................................................... 9
7 Maintenance ................................................................................................................................................... 10
Maintenance Schedule............................................................................................................................................ 10
Trouble Shooting..................................................................................................................................................... 10
8 Decommission................................................................................................................................................. 10
9 Transportation and Storage ............................................................................................................................ 10
Transportation ........................................................................................................................................................ 11
Storage
10 Disposal ........................................................................................................................................................... 11
11 Calibration ....................................................................................................................................................... 11
Proprietary Calibration............................................................................................................................................ 11
DKD-Calibration....................................................................................................................................................... 11
Re-Calibration ......................................................................................................................................................... 11
12 Data Sheet ....................................................................................................................................................... 11

T8 Torque Sensor Operation Manual
Interface Inc. ● 7401 East Butherus Drive, Scottsdale, Arizona 85260 USA ● Phone [phone] ● Fax [phone]
www.interfaceforce.com ● Email: [e-mail] ● 800.947.5598
Page 4 of 11
1 Read First
Safety and Caution Symbols
Caution:
Injury Risk for Persons
Damage of the Device is possible.
Note:
Important points to be considered.
Intended Use
Torque sensors are intended for the measurement of torques. The valid safety regulations should be absolutely
respected. The torque sensors are not safety components in the sense of the intended use. The sensors need to be
transported and stored appropriately. The assembly, commissioning and disassembling must take place
professionally.
Dangers
The torque sensor is fail-safe and corresponds to the state of technology.
Neglecting of Safety Notes
At inappropriate use, remaining dangers can emerge (e.g. by untrained personnel). The operation manual must be
read and understood by each person entrusted with the assembly, maintenance, repair, operation and
disassembly of the torque sensor.
Remaining Dangers
The plant designer, the supplier, as well as the operator must plan, realize and take responsibility for safety-related
interests for the sensor. Remaining dangers must be minimized. Remaining dangers of the torque measurement
technique must be pointed out.
Human mistakes must be considered. The construction of the plant must be suitable for the avoidance of dangers. A
danger-analysis for the plant must be carried out.
Reconstructions and Modifications
Each modification of the sensors without our written approval excludes liability on our part.
Personnel
The installation, assembly, commissioning, operation and the disassembly must be carried out by qualified
personnel only. The personnel must have the knowledge and make use of the legal regulations and safety
instructions.
Warning Notes
Attention must be paid to the accident prevention regulations of the trade associations. Coverings
and casings are necessary before operating the sensor. This is also valid for commissioning,
maintenance and trouble shooting.
Duties of the coverings and casings are:
•Protection from detaching parts
•Protection from contusion and shear
•Prevention from reaching rotating parts
•Prevention from being tangled up and/or getting caught by parts
Coverings may:
oNot grind
oNot rotate
Coverings are also necessary outside of operating and motion travel areas of persons. These
demands can be modified if other sufficient safety devices are available. During operation, the
safety precautions must be operative. By vibrations, damages can occur at the device.

T8 Torque Sensor Operation Manual
Interface Inc. ● 7401 East Butherus Drive, Scottsdale, Arizona 85260 USA ● Phone [phone] ● Fax [phone]
www.interfaceforce.com ● Email: [e-mail] ● 800.947.5598
Page 5 of 11
M
2 Term Definitions
Terms
Measuring Side:
Mechanical connection of the torque sensor in which the torque to be measured is applied. Usually this side has
the smallest moment of inertia.
Drive Side:
Mechanical connection of the torque sensor on the opposite side of the measuring side, usually with the largest
moment of inertia. At static torque sensors the housing is fastened on this side.
Low Torque Resistance Side:
The shaft of the arrangement (drive, load) which can be turned considerably smaller with torque than the nominal
torque of the torque sensor M << Mnenn .
Definition of the Pictograms on the Torque Sensor
The measuring side of the torque sensor is designated as follows:
Measuring side: or M
More information can be found on the data sheet, if needed.
3 Product Description
The sensor measures static and dynamic torques. The mounting position of the torque sensor is
horizontally.
Caution: it is to be differentiated between measuring side and drive side, see data sheet of the sensor:
http://www.Interfaceforce.com
Mechanical Setup
The sensors consist of a torsion shaft with free round shaft ends. The torsion shaft, applied with two strain gauge
full bridges, is bedded in a housing through ball bearings. For the signal transmission and/or the supply of the
strain gauge full bridges, a rotating transformer, according to the principle of a transformer, is arranged in the
sensor. For supply and measuring signal conditioning, electronics are integrated in the stator and the rotor.

T8 Torque Sensor Operation Manual
Interface Inc. ● 7401 East Butherus Drive, Scottsdale, Arizona 85260 USA ● Phone [phone] ● Fax [phone]
www.interfaceforce.com ● Email: [e-mail] ● 800.947.5598
Page 6 of 11
Electrical Setup
The electronics integrated in the sensor consists of two parts. The
first part is in the stator and has following tasks:
Stabilization of the supply voltage
Electric supply of the rotor electronics through the rotating transformer
Preparation of the measurement signal from the rotor
Readout of the torque measurement signal to the cable connection
The second part of the electronics is placed in the rotor of the torque sensor and
has following functions:
Supply of the SG full bridge with d.c. voltage Preparation of
the electrical torque measurement signal Transmission of
the measurement signal to the stator
4 Mechanical Assembly
For the assembly of a torque sensor in a shaft line, we always recommend to use couplings which can be misaligned.
Couplings
We recommend multi-disc couplings for our torque sensors. Couplings must be able to balance an axial, radial or
angular offset of the shafts and not allow large forces to act on the sensor. The assembly instructions of the
respective coupling manufacturer must be considered.
Misalignment Possibilities of Single-Jointed Couplings
Angular Misalignments Axial Misalignments
Note: Radial misalignments are only possible in the combination of
single-jointed coupling - torque sensor (as adapter) - single-jointed coupling.
Thus, with both single-jointed couplings the torque sensor forms a double-jointed coupling.
Radial Misalignments
Double-Jointed Couplings
Double-jointed couplings are used for the balance of inevitable angular, axial and radial misalignments.
Alignment of the Measurement Arrangement
Precisely alignment of the couplings reduces the reaction forces and increases the durability of the couplings.
Disturbance variables are minimized as well.
Due to the multitude of applications, an alignment of the coupling with a straight edge in two levels, vertical
to each other, is sufficient.
However, in drives with high speed an alignment of the coupling (shaft ends) with a dial gauge or a laser is
recommended.
For further references see coupling manual.
General
Before the assembly, shafts must be cleaned with dissolver (e.g. acetone), no foreign
particles may adhere to them. The hub must fit corresponding to the connection.
During the assembly, the sensor must be supported to protect it from falling down.

T8 Torque Sensor Operation Manual
Interface Inc. ● 7401 East Butherus Drive, Scottsdale, Arizona 85260 USA ● Phone [phone] ● Fax [phone]
www.interfaceforce.com ● Email: [e-mail] ● 800.947.5598
Page 7 of 11
Connections with Clamping Piece:
The indications of the clamping piece manufacturer must be considered. The clamping piece must be able to
transfer the arising torques safely.
Caution: During the assembly inadmissibly large forces may not act on the sensor or the couplings. At
small torques (< 20 N·m) connect the sensor electrically during the assembly and observe the signal,
the measurement signal may not exceed the limit values
Torque Sensors below 20 N·m
Sensors with nominal torques below 20 N·m are very sensitive to overload, therefore these
sensors need to be handled with greatest caution.
1. Connect the sensor electrically during the assembly and observe the measuring signal; the limit values
may not be exceeded in any case.
2. Align the arrangement before the parts are connected firmly.
3. Assemble the sensor at the low torque resistance side first, then at the stationary side (this avoids
impermissibly large torques from acting on the sensor).
4. Counter-hold by hand, so that impermissibly large torques or disturbance variables cannot act on the
torque sensor.
Torque Sensors from 20 N·m and above
The hub must fit corresponding to the connection.
Free-floating Assembly
The sensor is installed between two single-jointed couplings and contributes to the balance of an
inevitable axis offset between the two mechanical connections.
If no couplings are used, very large transverse forces can affect the sensor. In addition, large forces occur on the
bearings, in drive and output, which limit their life span very strongly.
Shafts must be cleaned with solvent (e.g. acetone) before the assembly. No foreign particles may adhere to them.
Shift couplings on shafts (use entire clamping length of the coupling) and align shafts. Absolutely assure that the
data of the couplings (axis offset, angular offset, tension, compression) are not exceeded.
The housing must be protected from twisting e.g. by a flexible connection. The cable connection may not be used
for this.
The cable connection must be placed loosely (form of goose neck), so that it can follow the light
movements of the stator.
Torque sensor
Drive Single-jointed coupling Single-jointed coupling Output
Flexible connection for
housing fixation
Cable connection
In this case, with both single-jointed couplings, the torque sensor forms a double-jointed coupling. A
single-jointed coupling can only balance axial and angular misalignments.
In this installation case, double-jointed couplings cannot be used for both sides!
Risk of Breakage!

T8 Torque Sensor Operation Manual
Interface Inc. ● 7401 East Butherus Drive, Scottsdale, Arizona 85260 USA ● Phone [phone] ● Fax [phone]
www.interfaceforce.com ● Email: [e-mail] ● 800.947.5598
Page 8 of 11
Drive
Double-jointed coupling
Double-jointed coupling
Output
Foot Version Assembly
The sensor can be installed as a bearing block. A double-jointed coupling must be mounted on each shaft end. By
this, inevitable axis offsets, which can also appear during the period of operation, are being balanced. If no
couplings are used, very large transverse forces can occur in the bearings of the sensor as well as in the bearings on
drive and output which will limit their life span very strongly. Further, large bending moments will emerge in the
shaft.
At small torques (< 20 N·m) connect the sensor electrically and observe the signal; the measurement signal
may not exceed the limit values...
Shafts must be cleaned with solvent (e.g. acetone) before the assembly. No foreign particles may adhere to them.
Shift couplings on shafts (use entire clamping length of the coupling) and align shafts. Absolutely assure that the
data of the couplings (axis offset, angular offset, tension, compression) are not exceeded.
Torque sensor
5 Electrical Connection
Pin Connection
Also see test certificate.
The firmly connected cable has free ends
Green Excitation GND 0 V
Brown Excitation + 12 ... 28 VDC
Yellow Signal ±5 V / (±10 V)
White Signal GND 0 V
Netting Shield
Cable
Only use a shielded cable with preferably small capacity. We recommend measuring cables from our product
range. They have been tested in combination with our sensors and meet the metrological requirements.
Shielding Connection
In combination with the sensor and the external electronics, the shield forms a Faraday Cage. By this, electro-
magnetic disturbances do not have any influence on the measurement signal.
Running of Measuring Cables
Do not run measuring cables together with control or heavy-current cables. Always assure that a large distance is
kept to engines, transformers and contactors, because their stray fields can lead to interferences of the measuring
signals.
If troubles occur through the measuring cable, we recommend to run the cable in a grounded steel conduit.

T8 Torque Sensor Operation Manual
Interface Inc. ● 7401 East Butherus Drive, Scottsdale, Arizona 85260 USA ● Phone [phone] ● Fax [phone]
www.interfaceforce.com ● Email: [e-mail] ● 800.947.5598
Page 9 of 11
6 Measuring
Engaging
The warming-up period of the torque sensor is approx. 5 min. Afterwards the measurement can be started.
The warming-up period of the torque sensor is approx. 5 min.
Direction of Torque
Torque means clockwise or clockwise torque if the torque acts clockwise when facing the shaft end. In this case a
positive electrical signal is obtained at the output.
Torque sensors by Interface can measure both, clockwise and counter-clockwise direction.
Static / Quasi-Static Torques
Static and/or quasi-static torque is a slowly changing torque.
The calibration of the sensors occurs statically on a calibration device. The
applied torque may accept any value up to the nominal torque.
Dynamic Torques
General
The static calibration procedure of torque sensors is also valid for dynamic applications.
Note: The frequency of torques must be smaller than the natural frequency of the mechanical
measurement setup.
The band width of alternating torque must be limited to 70 % of the nominal torque.
Natural Resonances
Estimate of the mechanical natural frequencies: c
f0 ฀1
฀
2 ฀
฀
f0
J1, J2
c
= Natural Frequency in Hz
= Moment of Inertia in kg*m² J2
= Torsional Rigidity in Nm/rad J1
Further methods for the calculation of natural resonances are corresponding purchasable programs or books
(e.g. Holzer-Procedure, Dubbel, Taschenbuch für den Maschinenbau, Springer Verlag)
An operation of the device in natural resonance can lead to permanent damages.
Speed Limits
The maximum speed indicated in the data sheet may not be exceeded in any operating state...
Disturbance Variables
By disturbances, measured value falsifications can occur by
•Vibrations,
•Temperature gradients,
•Temperature changes,
•Arising disturbance variables during operation, e.g. imbalance,
•Electrical disturbances,
•Magnetic disturbances,
•EMC (electromagnetic disturbances),
Therefore avoid these disturbance variables by decoupling of vibrations, covers, etc.
c
⋅
1 +
1 


J
1
J
2 


T8 Torque Sensor Operation Manual
Interface Inc. ● 7401 East Butherus Drive, Scottsdale, Arizona 85260 USA ● Phone [phone] ● Fax [phone]
www.interfaceforce.com ● Email: [e-mail] ● 800.947.5598
Page 10 of 11
7 Maintenance
Maintenance Schedule
Action
Frequency
Date
Date
Date
Control of cables and connectors
1x p.a.
Calibration
< 26 months
Control of fixation (flanges, shafts)
1x p.a.
Have bearings exchanged by Interface
20000 hrs
operating time
Trouble Shooting
This chart is used for searching for the most frequent errors and their elimination
Problem Possible Cause Trouble Shooting
No signal
No sensor excitation
•Outside of permissible range
•Connect excitation
•Cable defect
•No mains supply
Signal output connected wrong
•Connect output correctly
•Evaluation electronics defect
Sensor does not react to torque
Shaft not clamped
•Clamp correctly
No power supply
•Outside of permissible range
•Connect supply
•Cable defect
•No mains supply
Cable defect
•Repair cable
Connector connected wrong
•Connect correctly
Signal has dropouts
Axial position rotor to stator
outside of tolerance
•Align rotor
Cable defect
•Repair cable
Zero point outside of tolerance
Cable defect
•Repair cable
Shaft mounted distorted
•Mount correctly
Distorted shaft string
•Release from distortion
Strong lateral forces
•Reduce lateral forces
Distorted flanges
•Check evenness of flange-
surfaces
Shaft overloaded
•Send to manufacturer
Wrong torque indication
Calibration not correct
•Re-calibrate
Sensor defect
•Repair by manufacturer
Torque shunt
•Eliminate shunt
Oscillations
Alignment of shaft not correct
•Align correctly
Unbalance
•Balance the corresponding
parts
8 Decommission
All sensors must be dismantled professionally. Do not strike sensor housings with tools. Do not apply bending
moments on the sensor, e.g. through levers. The torque sensor must be supported to avoid falling down during the
dismantling.
9 Transportation and Storage
The transportation of the sensors must occur in suitable packing.
For smaller sensors, stable cartons which are well padded are sufficient (e.g., air cushion film, epoxy crisps, paper
shavings). The sensor should be tidily packed into film so that no packing material can reach into the sensor (ball
bearings). Larger sensors should be packed in cases.

T8 Torque Sensor Operation Manual
Interface Inc. ● 7401 East Butherus Drive, Scottsdale, Arizona 85260 USA ● Phone [phone] ● Fax [phone]
www.interfaceforce.com ● Email: [e-mail] ● 800.947.5598
Page 11 of 11
Transportation
Only release well packed sensors for transportation. The sensor should not be able to move back and forth in the
packing. The sensors must be protected from moisture.
Only use suitable means of transportation.
Storage
The storage of the sensors must occur in dry, dust-free rooms, only.
Slightly lubricate shafts and flanges with oil before storing (rust).
10 Disposal
The torque sensors must be disposed according to the valid provisions of law. For
this, see our “General Terms and Conditions” www.Interfaceforce.com
11 Calibration
At the time of delivery, torque sensors have been adjusted and tested with traceable calibrated measuring
equipment at factory side. Optionally, a calibration of the sensors can be carried out.
Proprietary Calibration
Acquisition of measurement points and issuing of a calibration protocol Traceable calibrated measuring equipment is
being used for the calibration. The sensor data are being checked during this calibration.
DKD-Calibration
The calibration of the sensor is carried out according to the guidelines of the DKD. The surveillance of the
calibrating-laboratory takes place by the DKD. At this calibration, the uncertainty of measurement of the torque
measuring instrument is determined. Further information can be obtained from Interface.
Re-Calibration
The recalibration of the torque sensor should be carried out after 26 months at the latest.
Shorter intervals are appropriate:
•Overload of the sensor
•After repair
•After inappropriate handling
•Demand of high-quality standards
•Special traceability requirements
12 Data Sheet
See www.Interfaceforce.com