HBM U2A User manual
A1261-2.2 en/de/fr
Load cells
Wägezellen
Pesons
U2A
Mounting instructions
Montageanleitung
Notice de montage
English Page 3 − 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Deutsch Seite 19 − 34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Français Page 35 − 50. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Contents Page
Safety instructions 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Conditions at the site of installation 7. . . . . . . . . . . . . . . . . . . . . . . . . .
1.1 Ambient pressure 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Special information 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Mounting instructions 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Load introduction 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Connection 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1 Notes on cable routing 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2 Connection technique 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3 Parallel connection of more than one transducer 10. . . . . . . . . . . . . .
4.4 Connections using the four-wire technique 10. . . . . . . . . . . . . . . . . . .
4.5 Cable extension 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6 Notes on cable routing 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Specifications 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1 Mechanical Data 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2 Options 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 Dimensions (in mm; 1 mm = 0.03937 inches) 13. . . . . . . . . . . . . . . . . .
6.1 Transducer 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2 Mounting accessories 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Safety instructions
In cases where a breakage would cause injury to persons or damage to
equipment, the user must take appropriate safety measures (such as fall
protection, overload protection, etc.). For safe and trouble-free operation, the
load cell must not only be correctly transported, stored, sited and installed but
must also be carefully operated and maintained.
It is essential to comply with the relevant accident prevention regulations. In
particular you should take into account the limit loads quoted in the
specifications.
Use in accordance with the regulations
U2A... type load cell is conceived for weighing applications. Use for any
additional purpose shall be deemed to be not in accordance with the
regulations.
In the interests of safety, the load cell 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 load cell is not safety element within the meaning of its use as intended.
Proper and safe operation of this load cell requires proper transportation,
correct storage, assembly and mounting and careful operation and
maintenance.
General dangers due to non-observance of the safety instructions
The U2A... load cell correspond to the state of the art and are fail-safe. The
load cell can give rise to residual dangers if it is 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 load cells covers only a small
area of weighing technology. In addition, equipment planners, installers and
operators should plan, implement and respond to the safety engineering
considerations of weighing technology in such a way as to minimize residual
dangers. Prevailing regulations must be complied with at all times. There must
be reference to the residual dangers connected with weighing technology.
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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 enables the manufacturer to guarantee that the product
complies with the requirements of the relevant EC directives (the declaration
of conformity is available at http://www.hbm.com/HBMdoc).
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HBM A1261−2.2 en/de/fr
Environmental conditions
In the context of your application, please note that all materials which release
chlorine ions will attack all grades of stainless steel and their welding seams.
In such cases the operator must take appropriate safety measures.
Prohibition of own conversions and modifications
The load cell 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 load cell 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.
Accident prevention
Although the specified nominal capacity 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.
Option: Explosion proof version
•Users must comply with all relevant erection regulations during installation.
•The installation conditions listed in the certificate of conformity and/or type
examination certificate must be complied with.
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1 Conditions at the site of installation
1.1 Ambient pressure
The ambient pressure for transducers may be between 0 and 5 bar. Please
note that pressure changes may shift the zero output signal.
Nominal (rated) load kg
t50 100 200 500 1 2 5 10 20
Change of zero point
[%/10 mbar] 0.065 0.032 0.016 0.006 0.003 0.006 0.003 0.002 0.001
1.2 Special information
The U2A transducers are produced entirely from non-rusting materials. The
user must test for resistance to aggressive environmental conditions in each
individual case.
2 Mounting instructions
•Handle the transducer carefully.
•The transducer seating must be horizontal, even and, together with the
transducer mounting surface, it must be absolutely clean.
•Dust, dirt and other particles are not to accumulate such that they affect the
load cell’s mobility and thus falsify the measured value. Use a cover plate to
protect the load cell from external mechanical influences.
•Do not overload the transducers (e.g. by unevenly distributed loads; if
necessary, provide overload protection (e.g. supports).
•Each transducer shoulb be shunted by a stranded copper cable (approx.
16 mm2) during or immediately after installation, in order to prevent any
welding or lightning currents flowing through the transducer.
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HBM A1261−2.2 en/de/fr
3 Load introduction
The transducers of the series U2A measure tension as well as compression
loads in the axial direction.
A threaded bolt on top of the housing and an internal thread on the adapter
are provided for the application of tensile loads (preferred direction).
HBM recommends the use of knuckle eyes to provide a connection free of
side force and moment. Knuckle eyes are suitable for use under quasi-static
loading (alternating load v10 Hz). When used under alternating loads, it is
essential that the transducer is installed without any axial play.
Please note the listed tightening torques for screw connecting the threaded
bolt and internal thread. Under no circumstances must these tightening
torques reach the transducer. If used without an adapter, make sure that the
bearing surface is clean and carefully machined flat and that the screw
connections are tightened properly at the base of the load cell.
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4 Connection
4.1 Notes on cable routing
Electrical and magnetic fields often cause the introduction of disturbing
voltages into the measuring circuit.
Please note the following hints:
•Use only screened, low capacitance measuring cable (cable from HBM
fullfills these requirements).
•Do not lay the measuring cable parallel to power and control lines. If this is
not possible (e.g. in cable ducts), the measuring cable can be protected,
e.g. by steel conduit.
•The stray fields of transformers, motors and contactors must be avoided.
4.2 Connection technique
Strain-gage based load cells can be connected to:
•carrier frequency
•DC-measuring amplifiers.
The transducer connection is implemented using the six-wire technique. The
connection assignment can be taken from the following illustration.
wh (white)
bk (black)
gy (grey)
Shield / filler connected with housing
gr (green)
rd (red)
−
Excitation (−)
Sense
Signal (+)
bu (blue) Sense
Signal (−)
Excitation (+)
Wiring code (6-wire−technique)
Fig. 4.1: Transducer with six-core cable
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HBM A1261−2.2 en/de/fr
4.3 Parallel connection of more than one transducer
The transducers are connected in parallel electrically by joining together the
core ends of the transducer connection cables having the same color.
ATTENTION
An overload of individual load cells cannot be detected from the output
signal.
4.4 Connections using the four-wire technique
With connections to amplifiers using the four-wire technique the cores bu
(blue) and gn (green) should be connected together, as should bk (black) and
gr (grey). Please take in account that this causes deviations to the sensitivity
and the temperature coefficient of sensitivity that this causes.
4.5 Cable extension
Extension cables must be screened and of the low capacitance type. We
recommend the use of HBM cables which fulfil these requirements. For cable
extensions, care must be taken to ensure a satisfactory connection with the
lowest possible transfer resistance and goog insulation.
When using the six-wire technique, the effects of resistance changes in the
extension cable are compensated. If you extend the cable with the four-wire
technique, the sensitivity deviation can be rectified by adjustment.
Temperature effects though are only compensated with the operation using
six-wire technique.
4.6 Notes on cable routing
The load cell connecting cable should be routed so that any condensed water
or dampness forming on the cable can drip off. It must not be led to the load
cell. In addition, it must be ensured that no dampness can penetrate the open
end of the cable.
This manual suits for next models
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