HBM CFT User manual

Operating Manual | Bedienungsanleitung |
Manuel d'emploi | Istruzioni per l'uso | 
English Deutsch Français Italiano 
CFT

Hottinger Baldwin Messtechnik GmbH
Im Tiefen See 45
D-64293 Darmstadt
Tel. [phone]
Fax [phone]
[email protected]
www.hbm.com
Mat.: 7-0111.0003
DVS: A02529_04_YCI_00 HBM: public
03.2019
EHottinger Baldwin Messtechnik GmbH.
Subject to modifications.
All product descriptions are for general information only.
They are not to be understood as a guarantee of quality or
durability.
Änderungen vorbehalten.
Alle Angaben beschreiben unsere Produkte in allgemeiner
Form. Sie stellen keine Beschaffenheits- oder Haltbarkeits
garantie dar.
Sous réserve de modifications.
Les caractéristiques indiquées ne décrivent nos produits
que sous une forme générale. Elles n'impliquent aucune
garantie de qualité ou de durabilité.
Con riserva di modifica.
Tutti i dati descrivono i nostri prodotti in forma generica e non
implicano alcuna garanzia di qualità o di durata dei prodotti
stessi.
变更权利。
所有息是对我品性描。在性或性方
它并提。

Operating Manual | Bedienungsanleitung |
Manuel d'emploi | Istruzioni per l'uso | 
English Deutsch Français Italiano 
CFT

2A02529_04_YCI_00 HBM: public CFT
English
1 Safety instructions 3........................................
2 Markings used 7............................................
2.1 The markings used in this document 7..........................
3 Scope of supply and accessories 8..........................
3.1 Accessories (not included in the scope of supply) 8...............
4 General instructions for use 9...............................
5 Structure and mode of operation 10...........................
5.1 Force transducer operation 10..................................
6 Conditions on site 12........................................
6.1 Ambient temperature 12.......................................
6.2 Moisture and corrosion protection 12............................
7 Mechanical installation 13....................................
7.1 Important precautions during installation 13......................
7.2 General installation guidelines 14...............................
7.3 Force transducer installation 16.................................
7.3.1 Installation via central thread 16................................
8 Electrical connection 18......................................
9 Specifications 19............................................
10 Dimensions 21..............................................

Safety instructions
CFT A02529_04_YCI_00 HBM: public 3
1 Safety instructions
Intended use
Piezoelectric force transducers from the CFT type series are designed solely
for measuring static and dynamic compressive forces within the load limits
stated in the specifications. Any other use is not the intended use.
To ensure safe operation, it is essential to comply with the regulations in the
mounting instructions, the safety requirements listed below, and the data
specified in the supplied technical data sheets. It is also essential to observe
the applicable legal and safety regulations for the relevant application.
Force transducers are not intended for use as safety components. Please also
refer to the "Additional safety precautions" section. Proper and safe operation
of force transducers requires proper transportation, correct storage, setup and
mounting, and careful operation.
Load-carrying capacity limits
The information in the technical data sheets must be observed when using the
force transducers. The respective specified maximum loads in particular must
never be exceeded. The following limits set out in the technical data sheets
must not be exceeded:
SForce limits
SLateral force limits
SBreaking forces
SMaximum eccentricity
SPermissible dynamic loads
STemperature limits
Please note that when several force transducers are interconnected, the load/
force distribution is not always uniform. This means that one particular force
transducer may be overloaded even if the total of all the nominal (rated) force
for all sensors has not been reached yet.

Safety instructions
4A02529_04_YCI_00 HBM: public CFT
Use as machine elements
Force transducers can be used as machine elements. The "Load-carrying
capacity limits" section and the specifications to ensure the required overload
limit of your application must also be observed.
Accident prevention
The prevailing accident prevention regulations stipulated by the trade associa
tions must be taken into account, even though the breaking force is well in ex
cess of the full scale value.
Additional safety precautions
Force transducers cannot (as passive transducers) implement any (safety-rele
vant) cutoffs. This requires additional components and constructive measures,
for which the installer and operator of the plant is responsible.
In cases where a breakage or malfunction of the force transducer would cause
injury to persons or damage to equipment, the user must take appropriate
additional safety precautions that meet at least the applicable safety and acci
dent prevention regulations (e.g. automatic emergency shutdown, overload
protection, catch straps or chains, or other fall protection).
The electronic processor that processes the measurement signal should be
designed so that failure of the measurement signal cannot lead to secondary
failures.
General dangers when failing to follow the safety instructions
Force transducers are state-of-the-art and failsafe. Transducers can give rise
to residual dangers if they are mounted, installed, used and operated in
appropriately or by untrained personnel. Every person involved with setting up,
starting up, operating or repairing a force transducer must have read and un
derstood the mounting instructions and in particular the technical safety in
structions. Force transducers can be damaged or destroyed by non-designated
use of the force transducer or by non-compliance with the mounting and oper
ating manual, these safety instructions or other applicable safety regulations
when using the force transducers. A force transducer can break, particularly if
it is overloaded. The breakage of a force transducer can cause damage to
property or injury to persons in the vicinity of the force transducer.

Safety instructions
CFT A02529_04_YCI_00 HBM: public 5
If force transducers are not used as intended, or if the safety instructions or
specifications in the mounting and operating instructions are ignored, it is also
possible that a force transducer may fail or malfunction, with the result that per
sons may be injured or property damaged (due to the loads acting on or being
monitored by the force transducer).
The scope of supply and performance of the transducer covers only a small
area of force measurement technology, as measurements with piezoelectric
force transducers presuppose the use of electronic signal processing.
Equipment planners, installers and operators should always plan, implement
and respond to the safety engineering considerations of force measurement
technology in such a way as to minimize residual dangers. Pertinent national
and local regulations must be complied with.
Conversions and modifications
The design or safety engineering of the transducer must not be modified with
out our express permission. Any modification shall exclude all liability on our
part for any damage resulting therefrom.
Maintenance
The force transducers from the CFT series are maintenance free.
Disposal
In accordance with national and local environmental protection and material
recovery and recycling regulations, old transducers that can no longer be used
must be disposed of separately and not with normal household garbage.
If you require more information about disposal, please contact your local
authorities or the dealer from whom you purchased the product.

Safety instructions
6A02529_04_YCI_00 HBM: public CFT
Qualified personnel
Qualified personnel means persons entrusted with installing, mounting, starting
up and operating the product who possess the appropriate qualifications for
their work.
This includes people who meet at least one of these three requirements:
SKnowledge of the safety concepts of automation technology is a require
ment and as project personnel, you must be familiar with these concepts.
SAs automation plant operating personnel, you have been instructed how to
handle the machinery. You are familiar with the operation of the equipment
and technologies described in this documentation.
SAs commissioning engineers or service engineers, you have successfully
completed the training to repair the automation systems. Moreover, you are
authorized to start up, ground and label circuits and equipment in accor
dance with safety engineering standards.
It is also essential to comply with the legal and safety requirements for the rele
vant application during use. The same applies to the use of accessories.
The force transducer may only be installed by qualified personnel, strictly in
accordance with the specifications and with the safety requirements and regu
lations.

Markings used
CFT A02529_04_YCI_00 HBM: public 7
2 Markings used
2.1 The markings used in this document
Important instructions for your safety are highlighted. It is essential to follow
these instructions to prevent accidents and damage to property.
Symbol Meaning
WARNING This marking warns of a potentially dangerous situa
tion in which failure to comply with safety require
ments may result in death or serious physical injury.
CAUTION This marking warns of a potentially dangerous situa
tion in which failure to comply with safety require
ments may result in minor to moderate physical
injury.
Notice This marking draws your attention to a situation in
which failure to comply with safety requirements may
result in damage to property.
Important
This marking draws your attention to important infor
mation about the product or about handling the prod
uct.
Tip
This marking indicates tips for use or other informa
tion that is useful to you.
Information
This marking draws your attention to information
about the product or about handling the product.
Emphasis
See …
Italics are used to emphasize and highlight text and
identify references to chapters, diagrams, or external
documents and files.

Scope of supply and accessories
8A02529_04_YCI_00 HBM: public CFT
3 Scope of supply and accessories
SCFT piezoelectric force transducer
SMounting instructions
STest record
3.1 Accessories (not included in the scope of supply)
Accessories Ordering number
Connection cable for piezoelectric sensors with a 10-32UNF
plug on both sides. Available in different lengths up to 7 m
1-KAB143-x
Connection cable for piezoelectric sensors with a 10-32UNF
plug on one side and a BNC plug on the other cable end.
Available in different lengths up to 3 m
1-KAB176-x
Cable coupling to extend piezoelectric connection cables.
10-32UNF at both ends.
1-CCO
Summing box for parallel connection of up to four piezoelectric
sensors to one charge amplifier. Connector sockets: 10-32UNF
1-CSB4/1

General instructions for use
CFT A02529_04_YCI_00 HBM: public 9
4 General instructions for use
Force transducers are suitable for measuring compressive forces. They pro
vide highly accurate static and dynamic force measurements and must there
fore be handled very carefully. Particular care must be taken when transporting
and installing the devices. Dropping or knocking the transducer may cause per
manent damage.
The permissible limits for mechanical, thermal and electrical stresses are listed
in section “Specifications” on page 19. It is essential to take these limits into
account when planning the measuring set-up, during installation and,
ultimately, during operation.

Structure and mode of operation
10 A02529_04_YCI_00 HBM: public CFT
5 Structure and mode of operation
5.1 Force transducer operation
The force transducers from the CFT series operate in accordance with the
piezoelectric principle. Compressive forces are transmitted to the two gallium
phosphate measuring elements via the pre-stressed force application surfaces.
They separate the electrical charges in proportion to the force curve. Charges
are produced on the surface of the measuring elements that are forwarded by
an electrode between the measuring elements and the sensor housing to the
plug of the force transducer. If a charge amplifier is connected via a suitable
cable, the charge signal can be converted into a voltage signal or a digital force
signal.
Housing
Electrode
Piezoelectric crystals Pre-stress elements
Plug connection
Fig. 5.1 Basic structure of the CFT sensors

Structure and mode of operation
CFT A02529_04_YCI_00 HBM: public 11
Fig. 5.2 Appearance of CFT force transducers with nominal (rated) forces of 5 kN and
20 kN
Important
If you load the sensor with a force, either a charge amplifier has to be
connected or the inner contact of the plug for connecting the coaxial cable
must be short circuited with the shielding.

Conditions on site
12 A02529_04_YCI_00 HBM: public CFT
6 Conditions on site
CFT force transducers are made of stainless materials. The transducer must
still be protected from weather conditions such as rain, snow, ice, and salt
water.
6.1 Ambient temperature
The temperature has very little effect on the output signal. To obtain optimum
measurement results, comply with the nominal (rated) temperature range.
All CFT series sensors are mechanically pre-stressed with the corresponding
parts. The pre-stress force depends on the modulus of elasticity of the materi
als being used. Since the modulus of elasticity varies with the temperature, the
pre-stress force also varies with the temperature. The sensor forwards this
variation as a measurement signal to the charge amplifier. If you want to per
form quasi-static measurements (for example adjusting measurement chains),
we recommend bringing the measurement chain to a uniform and constant
temperature.
Please be aware that the drift of a piezoelectric measurement chain may
increase at a higher temperature, as the mobility of the charge carriers rises
with the temperature.
6.2 Moisture and corrosion protection
CFT series force transducers meet the conditions of degree of protection IP65
in accordance with EN60529, if a connection cable is connected.
With stainless steel force transducers, please note that acids and all materials
which release ions will also attack stainless steels and their weld seams. Any
resulting corrosion could cause the force transducer to fail. In this case, appro
priate protective measures must be provided. Force transducers should also
be protected against substances that attack stainless steels.

Mechanical installation
CFT A02529_04_YCI_00 HBM: public 13
7 Mechanical installation
7.1 Important precautions during installation
SHandle the transducer with care.
SNote the requirements for the force application parts in accordance with the
subsequent sections of these instructions.
SWelding currents must not be allowed to flow through the transducer. If
there is a risk that this might happen, you must use a suitable low-ohm
connection to electrically bypass the transducer. HBM provides the highly
flexible EEK ground cable for this purpose, for example, that is screwed on
above and below the transducer.
SMake sure that the transducer cannot be overloaded.
WARNING
There is a danger of the transducer breaking if it is exposed to heavy force
overshoot. This can cause danger for the operating personnel of the system in
which the transducer is installed.
Implement appropriate safety measures to avoid overloads or to protect
against the resulting dangers. The maximum possible mechanical stresses,
especially the breaking force,are noted in the specifications.
When installing and operating the transducers, please observe the maximum
parasitic forces – lateral forces, bending moments and torques (see section
“Specifications”, page 19) – and the maximum permissible load-carrying capac
ity of the force application parts used.

Mechanical installation
14 A02529_04_YCI_00 HBM: public CFT
Notice
Piezoelectric sensors should always be connected to a charge amplifier when
loads – particularly dynamic loads – are applied. Alternatively, it is also possi
ble to short circuit the sensors. The sensors could be destroyed if this informa
tion is ignored.
7.2 General installation guidelines
The forces to be measured must act on the transducer as accurately as possi
ble in the direction of measurement.
Bending moments resulting from lateral force, eccentric loading and the lateral
forces themselves, may destroy the transducer if limit values are exceeded.
Please comply with the limits in the specifications.
Be aware that you may then only utilize an individual parasitic load (bending
moments, lateral forces, torques) up to the limits stated in the specifications if
none of the other components occurs. If lateral forces, bending moments and
torques act on the sensor simultaneously, the components of the loading must
not exceed 100% when added together.
Example 1:
You are using 50 % of the allowed lateral force, 25 % of the bending moment
and 25% of the torque.
50 % + 25 % + 25 % = 100 %
→ The sensor is not overloaded and can be operated.
Example 2:
You are using 70 % of the allowed lateral force, 25 % of the bending moment
and 25% of the torque.
70 % + 25 % + 25 % = 120 %
→ The sensor is overloaded and must not be operated.

Mechanical installation
CFT A02529_04_YCI_00 HBM: public 15
Lateral force
Torque
Bending moment
Eccentric force application
Fig. 7.1 Parasitic loads: Bending moments, lateral forces, torque and eccentric force
application
If the force is not applied in the center of the force transducer, a bending
moment is produced that can be calculated as:
Mb=F*e
where F is the applied force and e is the distance between the force application
point and the center of the force transducer.

Mechanical installation
16 A02529_04_YCI_00 HBM: public CFT
7.3 Force transducer installation
The force must always be applied via the force application surfaces (see
Fig. 7.2)
Load application surface
Fig. 7.2 The force must always be applied via the load application surface
7.3.1 Installation via central thread
The sensors can be used for quasi-static measurements; the dynamic loads
are acquired correctly. The sensor must not be exposed to tensile forces. It is
not possible to measure tensile forces. The maximum tensile force can be
found in the specifications.
To guarantee minimum measurement uncertainty, the structural elements con
nected to the sensor should exhibit a roughness Ra< 0.8 μm and a hardness
of at least 40HRC.
The threads are used to screw the force transducer onto the load application
surfaces. The structural element on the customer side (e.g. profile, ceiling,
plate) must be sufficiently stiff in design so that there is no misalignment under
load (danger of adequate bending moments). See the following table Tab. 7.1
for the tightening torque for the screws.

Mechanical installation
CFT A02529_04_YCI_00 HBM: public 17
The screws to be used must exhibit a rigidity of 12.9.
Nominal
(rated)
force
Tightening
torque
Screws for
transducer
mounting
Screws Min. thread
reach
Max. thread
reach
kN N*m Number mm mm
5 0.5 M2.5 1 2.0 2.5
20 1.0 M4 1 2.5 3.5
Tab. 7.1 Screws and torque to be used

Electrical connection
18 A02529_04_YCI_00 HBM: public CFT
8 Electrical connection
Please use only high-insulation connection cables that generate little or no
triboelectricity. The HBM connection cables meet this condition (see section
“Scope of supply and accessories”, page 8).
You can connect CFT series sensors in parallel. The CSB summing box is
available for this purpose. If all of the sensors connected in parallel have the
same sensitivity, then the overall sensitivity is the same as the sensitivity of
each individual sensor.
Please be aware that measurements with piezoelectric sensors require very
high insulation resistances. Contaminations reduce insulation resistances con
siderably and therefore results in a strong drift. Therefore do not touch plugs or
sockets and screw on the protective cap when the sensor is not connected.