HBM C6A User manual

A0638−2.3 de/en/fr
Kraftaufnehmer
Force transducer
Capteur de force
C6A
Montageanleitung
Mounting instructions
Notice de montage

English Page 3 −26.................................................
Deutsch Seite 27 −50...............................................
Français Page 51 −74...............................................

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Contents Page
English
Safety instructions 4..............................................
1 Scope of supply 7.............................................
2 Area and method of use 7......................................
3 Structure and mode of operation 8..............................
3.1 Measuring element 8.......................................
3.2 Housing 9................................................
3.3 Measuring process, output signal 9..........................
3.4 Disturbance variables 9....................................
4 Conditions on site 10...........................................
4.1 Ambient temperature 10.....................................
4.2 Moisture 10................................................
4.3 External pressure 10........................................
4.4 Chemical effects 10.........................................
4.5 Deposits 10................................................
5 Mechanical installation 11.......................................
5.1 Important measures for installation 11.........................
5.2 General installation guidelines 12.............................
5.3 Installation examples 12.....................................
5.3.1 Force conductor with pressure plates 13.................
5.3.2 Force conductor with load button ZL and pendle bearing
EPO3 14............................................
5.3.3 Force conductor with spherical cap ZK 16................
5.3.4 Tensile force introduction with spherical cap ZK 17........
5.4 Safety measures 17.........................................
6 Connections 18.................................................
6.1 Instructions for cabling 18....................................
6.2 Wiring pin assignment 19....................................
7 Specifications 20...............................................
8 Dimensions of the transducer and mounting accessories 22.......
8.1 Transducer (free dimension tolerance median to DIN 7168) 22....
8.2 Mounting accessories 23....................................

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Safety instructions
Use in accordance with the regulations
Force transducers in the C6A range are designed for force measurements on
test benches/in press−fit devices/test devices/pressing. Use for any additional
purpose shall be deemed to be not in accordance with the regulations.
In the interests of safety, the transducer should only be operated as described
in the Mounting Instructions. It is also essential to observe the appropriate
legal and safety regulations for the application concerned during use. The
same applies to the use of accessories.
The transducer is not a safety element within the meaning of its use as
intended. Proper and safe operation of this transducer requires proper
transportation, correct storage, assembly and mounting and careful operation
and maintenance.
General dangers due to non-observance of the safety instructions
The C6A force transducer corresponds to the state of the art and is fail−safe.
The transducers can give rise to residual dangers if they are inappropriately
installed and operated by untrained personnel.
Everyone involved with the installation, commissioning, maintenance or repair
of a force transducer must have read and understood the Mounting
Instructions and in particular the technical safety instructions.
Residual dangers
The scope of supply and performance of the transducer covers only a small
area of force measurement technique. In addition, equipment planners,
installers and operators should plan, implement and respond to the safety
engineering considerations of force measurement technique in such a way as
to minimise residual dangers. Prevailing regulations must be complied with at
all times. There must be reference to the residual dangers connected with
force measurement technique.

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In these mounting instructions residual dangers are pointed out using the
following symbols:
Symbol: DANGER
Meaning: Highest level of danger
Warns of a directly dangerous situation in which failure to comply with safety
requirements will lead to death or serious physical injury.
Symbol: WARNING
Meaning: Possibly dangerous situation
Warns of a potentially dangerous situation in which failure to comply with
safety requirements can lead to death or serious physical injury.
Symbol: ATTENTION
Meaning: Possibly dangerous situation
Warns of a potentially dangerous situation in which failure to comply with
safety requirements could lead to damage to property, slight or moderate
physical injury.
Symbol: Note
Refers to the fact that important information is being given about the product
or its use.
Symbol:
Meaning: CE mark
The CE mark is the manufacturer’s guarantee that his product meets the
requirements of the relevant EC directives (the declaration of conformity is
available at http://www.hbm.com/HBMdoc).

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Prohibition of own conversions and modifications
The transducer must not be modified from the design or safety engineering
point of view except with our express agreement. Any modification shall
exclude all liability on our part for any damage resulting therefrom.
Qualified personnel
This instrument is only to be installed by qualified personnel strictly in
accordance with the technical data and with the safety rules and regulations
which follow. It is also essential to observe the appropriate legal and safety
regulations for the application concerned. The same applies to the use of
accessories.
Qualified personnel means persons entrusted with the installation, fitting,
commissioning and operation of the product who possess the appropriate
qualifications for their function.
Conditions on site
Protect the transducer from damp and weather influences such as rain, snow,
etc.
Maintenance
The C6A force transducer is maintenance free.
Accident prevention
Although the specified nominal force in the destructive range is several times
the full scale value, the relevant accident prevention regulations from the
trade associations must be taken into consideration.

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1 Scope of supply
•1 C6A force transducer
•1 C6A Operating Manual
Accessories (not included in the scope of supply):
•load button: 1−C6A/20T/ZL; 1−C6A/50T/ZL; 1−C6A/100T/ZL;
1−C6A/200T/ZL; 1−C6A/500T/ZL
•spherical cap: 1−C6A/50T/ZK; 1−C6A/100T/ZK; 1−C6A/200T/ZK;
1−C6A/500T/ZK
•pendle bearing - top: 1−EPO3R/20T; 1−EPO3/50T; 1−EPO3/100T;
1−EPO3/250T; 1−EPO3/500T
2 Area and method of use
The transducers are designed for the measurement of static and dynamic
pressure forces.
Tensile forces can also be measured with the transducers. The tension
elements required for this are attached to the top face of the transducer and
fed through the inner bore of the transducer so that tensile forces initiated via
the tension anchor act as pressure forces. The transducers can be installed in
any position for force measurement. The force conductor must however act in
the direction of the transducer axis.
HBM force transducers in this range measure dynamic forces in the load
direction just as precisely as static forces. In so doing the sum of the dynamic
loading and the static starting load must not exceed the nominal load.
The force transducers are maintenance − free and can be installed even in
poorly accessible places. Their electrical measurement signals can be
transmitted to remote measuring points and monitors in order to indicate and
register there and be used for control and regulating tasks.
As precision measuring instruments the force transducers must be handled
carefully during transport and mounting; impacts or dropping the transducer
could result in permanent damage. Loading impacts (e.g. applying a load in
”freefall”) in measuring mode can also result in unexpected overload with
lasting damage. Where such loading impacts cannot be ruled out they must
be checked.
The limits for the permissible mechanical stresses are stated in the
Specifications.

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3 Structure and mode of operation
3.1 Measuring element
The measuring element is a rotation−symmetrical body made of hardened
steel (Abb. 3.1).
If there is a loading in an axial direction the measuring element is upset. The
resulting strain is detected by a strain gauge which is connected to a
Wheatstone bridge.
Correction and compensation resistors are placed in the transducer circuit in
order to remove unwanted influences on the zero signal and sensitivity.
Nominal forces 0.2 − 2 MN Nominal force 5
MN
1 = measuring element; 2= enclosure; 3= strain gauge; 4= force−introduction surface;
5= base plate; F= direction of force
F
F
Abb. 3.1: Schematic drawing

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3.2 Housing
The housing protects the application from moisture and aggressive media. No
load or force may be initiated in the transducer via the housing.
The cable box is cast using a special casting compound and must not be
opened.
3.3 Measuring process, output signal
The force acting in the direction of measurement elastically deforms the
measuring spring and thus the S/G. The S/G changes its ohmic resistance in
proportion to the change in its length. The Wheatstone bridge is thereby
staggered. If an excitation voltage is applied the circuit provides an output
signal which is proportional to the change in resistance and thus also
proportional to the force applied.
The electrical connection of the transducer is executed in a six wire circuit
(see page 19).
3.4 Disturbance variables
Torsion, bending and transverse load are disturbance variables and are
therefore to be avoided. If necessary they can be remedied with HBM
mounting accessories (section 5.3).
The effects of temperature on the zero signal (S/G bridge and housing) and
on the sensitivity are compensated.
Changes in the ambient pressure act as additive (subtractive) forces. These
are scarcely of importance when compared with large nominal loads.

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4 Conditions on site
4.1 Ambient temperature
To achieve optimal measurement results the nominal temperature range must
be maintained. Constant but slowly changing temperatures are best.
Temperature gradients in the transducer caused by one−sided heating
(radiant heat) or cooling are very disruptive. A radiation shield and all−round
heat insulation bring about marked improvements. Naturally they must not
form a force shunt.
4.2 Moisture
External moisture and a tropical climate will not impair the function of the
transducer according to the classification of the specified degree of protection
(degree of protection IP 67 to DIN 40 050).
Transducers with nominal loads ≥1 MN are not metal−tight.
4.3 External pressure
The external pressure (in air) must be between 0 and 3 bar.
4.4 Chemical effects
The steel housing of the transducers is protected by a powder coating. If used
in difficult environmental conditions (direct weather effects, contact with media
which encourage corrosion) additional protective measures should be
employed by the user. The unit can be painted with commercial protective
paint or a tar−based coating (underseal). The sheath of the connection cable
is made of silicon rubber.
4.5 Deposits
Dust, dirt and other foreign bodies must not be allowed to accumulate such
that they divert part of the measured force onto the housing and so falsify the
measured value (force shunt).

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5 Mechanical installation
5.1 Important measures for installation
•Treat the transducer gently
•Use appropriate lifting tools
•The mounting surfaces (substructure and pressure plates) must
− maintain an evenness of 0.02 mm under all loading
− be free from grease and dust
•Do not overload the transducer, even temporarily e.g. through unevenly
distributed bearing loads
•During straightening work insert supporting bodies of the same height
(dummies) first if necessary.
WARNING
If there is a risk of breakage through overload on the transducer and
thus a risk to persons, additional safety measures are to be taken.

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5.2 General installation guidelines
The forces must act as accurately as possible in the direction of
measurement. Torsion and bending moments, eccentric loading and
transverse forces may result in measurement errors and if the limit values are
exceeded could destroy the transducer.
The transverse loads and lateral forces also include the corresponding
components of any measured quantities introduced diagonally. Eccentric force
or load need not be expected if both the substructure and the plan−parallel
hardened plate lying on the transducer or a built−in part (e.g. HRC42 − 46) are
at right angles to the transducer axis and are sufficiently unyielding (thick and
stiff).
Heat expansion of the structure between several bearing points where the
transducer is rigidly installed may also cause transverse stresses. If
necessary they can be remedied with HBM mounting accessories (section
5.3,Abb. 5.4). The following mounting accessories are available from HBM for
transducers in the C6A range:
•Load button ZL
•Spherical cap ZK
•Pendle bearing EPO3
The mounting accessories prevent transverse and diagonal stresses from
being introduced in the transducer.
5.3 Installation examples
The installation examples described and shown here do not claim to be
complete; rather they are intended as suggestions of the varied applications in
which the C6A transducer can be used.
Thus precise designs and calculations are to be prepared for each
application, in which for example the thickness of the pressure plate (see
table on page 14) or also the diameter, tensile strength, etc. of tension
anchors must be determined.

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5.3.1 Force conductor with pressure plates
This type of installation (Abb. 5.1 and Abb. 5.2) is possible with a central force
conductor and if no transverse forces occur.
Nominal forces 0.2 − 2
MN
Nominal force 5 MN
F = direction of force; 1= transducer; 4= pressure plate; 5= substructure; 7= centering disc
F
F
Abb. 5.1: Direction of force vertical
Nominal forces 0.2 − 2 MN
Nominal force 5 MN
F = direction of force; 1= transducer; 4= pressure plate; 5= substructure; 7= centering disc; 10= fixing
bolts
Abb. 5.2: Direction of force horizontal

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When planning the structure ensure that the pressure plates (4) (see Abb. 5.1
to Abb. 5.4) are hardened (HRC42 − 46) and ground so as to be plan−parallel
(evenness ±0.02 mm) (for minimum thickness see table below). The
substructure must be sufficiently unyielding. To centre the transducer with
nominal loads ≤2 MN it is recommended that centering discs (7) are used
(see Abb. 5.1 to Abb. 5.4). The exact dimensions of these discs which are to
be produced should match those of the centering discs of the loading heads
(section 8.2). If the transducer is fixed with the fixing bolts (10) (see Abb. 5.1,
Abb. 5.2 and Abb. 5.4) ensure that when the fixing bolts are screwed in the
maximum tightening torque MAspecified in the table below is not exceeded.
Nominal force MN 0.2 0.5 1 2 5 10
Maximum tightening torque MA*) N⋅m8 20 25 40 90 400
Thickness of the pressure plates where
HRC42 −46 mm >30 >40 >50 >70 >90 >120
*) for bolts of resistance class 8.8
If the bolts are tightened too firmly this will result in changes in the zero signal
and the characteristic values. If possible, the fixing bolts should not absorb
any lateral forces! They are to be screwed in with a liquid thread securing
medium.
5.3.2 Force conductor with load button ZL and pendle bearing EPO3
Only for nominal forces < 2
MN
F = direction of force; 1= transducer; 2= load button; 4= pressure plate; 5= substructure; 7= centering disc
F
Abb. 5.3: Rigid installation of the C6A with ZL and EPO3
No transverse forces may occur with this installation arrangement. Instead of
the pressure plate (4) the pendle bearing top section EPO 3 may be used with
load button ZL. For the execution of the substructure refer to section 5.3.1

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The execution as a pendle bearing shown in Abb. 5.4 allows lateral shifting of
a bearing point (max. diagonal position of the pendle bearing axis approx. 1 to
2°).
Only for nominal forces < 2 MN
F = direction of force; 1= transducer; 2= load button; 4= pressure plate; 5= substructure; 6= pendle bea-
ring top section EPO3; 7= centering disc; 10= fixing bolts
F
Abb. 5.4: Installation with pendle bearing EPO3
No transverse forces can thus occur in the bearing. The pendle bearings must
stand vertical in the normal case in order to allow lateral excursion. On
installation guide elements must be provided here.

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5.3.3 Force conductor with spherical cap ZK
In all C6A transducers the force can be conducted using a spherical cap. The
spherical cap may be placed both on top of the transducer (Abb. 5.5, drawing
a) and below the transducer (Abb. 5.5, drawing b).
FF
a) b)
Abb. 5.5: Installation with spherical cap ZK
The version shown in Abb. 5.5 (drawing a) has the disadvantage that lateral
forces act on the transducer if the direction of force conduction is not exactly
perpendicular to the plane A.
This disadvantage does not occur with the option shown in Abb. 5.5 (drawing
b). However, here it must be taken into consideration that the transducer must
possibly be given a small preliminary load to avoid tipping over the structure.
Nominal force 5 MN F
Abb. 5.6: Example of force conductor with spherical cap ZK
For details of the base plate, substructure and pressure plate refer to section
5.3.1 . Three centering pins are included in the scope of supply for the
spherical cap for centering the cap with the transducer of nominal force ≤2
MN. With transducers of nominal force 5 MN the cap can be bolted onto the
transducer.

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5.3.4 Tensile force introduction with spherical cap ZK
Thanks to its inner bore, the C6A transducer designed for compressive
loading (nominal force ≤2 MN) can also be used for measuring tensile loading
(Abb. 5.7).
Nominal forces < 2 MN
F = direction of force; 1= transducer; 3= spherical cap; 4= pressure plate; 5= substructure; 7= centering
disc; 8= centering ring; 9= centering pins (3 on circumference); 11= tension anchor (tension rope);
12= tensioning nut; 13= retaining ring
F
Abb. 5.7: Installation for tensile loading
To do this the tension element is fed through the inner bore of the transducer.
The tensile force then acts like a compressive loading. Here the tensile
strength of the tension element used is particularly to be noted since − due to
the diameter of the inner bore of the transducer − high tension stresses occur
at the nominal load.
Please note in particular section 5.4 (“Safety measures).
5.4 Safety measures
An overload cut−out should be provided wherever possible. Due to the small
displacements (see Specifications) the stops must be able to be set very
finely and secured well. The overload cut−out should not prevent
measurement at up to 120 % of the nominal force and be fully effective from
140 % of the nominal force.
Fall safety devices must additionally be provided, particularly where overload
could result in personal injury.

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6 Connections
6.1 Instructions for cabling
Electrical and magnetic fields often cause the induction of noise/interference
voltage in the measuring circuit. This interference is primarily caused by
high−power transmission lines parallel to the measuring leads, but also by
contactors and electric motors in the vicinity.
Please note the following instructions:
•Always use shielded, low−capacity measurement cable (HBM cables meet
these requirements).
•Do not lay measurement cable parallel to high−voltage power lines or
control circuits. If this is not possible (e.g. in cable ducts) protect the
measurement cable, e.g. with armoured steel tube and maintain a minimum
distance of 50 cm from the other cables. High−voltage power lines and
control lines should be twisted (15 turns per metre).
•Avoid stray fields of transformers, motors and contactors.
•Do not earth transducer, amplifier and display device more than once. All
the devices in the measuring chain are to be connected to the same
earthed conductor.
•The screen of the connection cable is connected to the transducer housing.

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6.2 Wiring pin assignment
The connection cable of the transducer has colour−coded free wire ends. The
cable shielding is connected in accordance with the Greenline concept. This
means that the measurement system is surrounded by a Faraday cage.
Electromagnetic interference will not affect the measurement system.
Connectors to CE standard are to be fitted at the free end of the transducer.
The shielding is here to be laid over the whole area.
If a different connection technique is used then good EMC shielding is to be
provided in the wiring loom, the shielding again being laid over the full area
(see also HBM Greenline Information, document G36.35.0).
If the transducer is connected according to the following connection diagram
then when the transducer has compressive loading the output voltage at the
measuring amplifier is positive.
wh (white)
bk (black)
rd (red)
bl (blue)
gn (green)
gy (grey)
shielding
Measurement signal (+) UA
Excitation voltage (+) UB
Sense lead (−)
Sense lead (+)
Excitation voltage (−) UB
Measurement signal (−) UA
Cable shielding, connected to housing
Six−wire connection
Fig. 6.1: Pin assignment for the C6A

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7 Specifications
Type C6A
Accuracy class 0.5
Nominal force Fnom MN 200 kN 500 kN 1 MN 2 MN 5 MN
Nominal sensitivity Cnom mV/V 2
Relative sensitivity deviation1)
when used with hardened pressure
plates
when used with load button ZL and
pendle bearing EPO3
dc
%
%
<"2.5
<"0.5
when used with spherical cap ZK %<"2.5 <"4
Relative zero signal deviation ds,o %<1
Relative range of inversion (0.5Fnom) u % <"0.8
Linearity deviation1)
when used with hardened pressure
plates
when used with load button ZL and
pendle bearing EPO3
dlin
%
%
<"1
<"0.5
when used with spherical cap ZK %<"1
Effect of temperature on sensiti-
vity/10 K by reference to sensitivity TKc%<"0.1
Effect of temperature on zero si-
gnal/10 K by reference to sensitivity TK0%<"0.05
Creep over 30 min, in nominal tempera-
ture range2) dcrF+E %<"0.06
Input resistance at reference
temperature ReΩ>345
Output resistance at reference
temperature RaΩ356"1.5
Isolation resistance at test voltage
100 V Ris GΩ>5x109
Reference excitation voltage Uref V 5
Operating range of the excitation
voltage BU,GT V0.5 − 12
Reference temperature tref °C +23
Nominal temperature range Bt,nom °C−10...+70
Operating temperature range Bt,G °C−30...+85
Storage temperature range Bt,S °C−50...+100
1) The difference in tolerances when using different mounting accessories is due to the low overall height of
the transducer.
2) By reference to nominal force