HBM RTN User manual

Mounting Instructions | Montageanleitung |
Notice de montage
English Deutsch Français
RTN

Hottinger Baldwin Messtechnik GmbH
Im Tiefen See 45
D-64293 Darmstadt
Tel. [phone]
Fax [phone]
[email protected]
www.hbm.com
Mat.: 7-0101.0030
DVS: A01153_03_Y00_01 HBM: public
04.2020
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 durablilité.

Mounting Instructions | Montageanleitung |
Notice de montage
English Deutsch Français
RTN

2A01153_03_Y00_01 HBM: public RTN
English
1 Safety instructions 3........................................
2 Markings used 7............................................
2.1 Markings used in this document 7..............................
2.2 Symbols on the device 7......................................
3 Application 8...............................................
4 Mounting instructions 9.....................................
5 Electrical connection 12......................................
5.1 Connection in a 4-wire configuration 12..........................
5.2 Plug connection (optional) 13...................................
5.3 Parallel connection of several transducers 14.....................
5.4 Shortening and extending the cable 14..........................
5.5 EMC protection 15............................................
6 Corrosion protection and maintenance 17.....................
7 Specifications 18............................................
8 Dimensions of the RTN... load cell 19.........................
9 Mounting accessories 21.....................................

Safety instructions
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1 Safety instructions
Intended use
Load cells of the RTN…type series are designed for technical weighing
applications within the load limits detailed in the specifications. Any other use is
not the intended use.
The load cells may only be installed by qualified personnel in compliance with
the specifications and with the safety requirements and regulations of these
mounting instructions. It is also essential to observe the applicable legal and
safety regulations for the application concerned. The same applies to the use
of accessories.
Load cells are not intended for use as safety components. Please also refer to
the “Additional safety precautions” section. Proper and safe operation of the
load cells requires proper transportation, correct storage, siting and mounting,
and careful operation.
Load-carrying capacity limits
Comply with the data in the technical data sheets when using the load cells.
The respective specified maximum loads in particular must never be exceeded.
Do not exceed the values stated in the technical data sheets, for example, for
Slimit load
Slateral load limiting
Sbreaking loads
Stemperature limits
Slimits of electrical load-carrying capacity
Note that when several load cells are installed in a scale, there is not always an
even load distribution on the individual load cells.
Use as machine elements
The load cells can be used as machine elements. When used in this manner, it
must be noted that, to favor greater sensitivity, the load cell is not designed
with the safety factors usual in mechanical engineering. Please refer to the
“Load-carrying capacity limits” section and the specifications.

Safety instructions
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Accident prevention
The applicable accident prevention regulations from employers’ liability
insurance associations must be taken into account, even though the stated
load in the destructive range is well in excess of the full scale value.
Additional safety precautions
Load cells cannot (as passive transducers) implement any (safety-relevant)
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 load cells would cause injury
to persons or damage to equipment, the user must take appropriate additional
safety measures that meet at least the requirements of applicable safety and
accident 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 of failing to follow the safety instructions
Load cells are state-of-the-art and reliable. Transducers can give rise to
residual dangers if they are mounted, installed, used and operated
inappropriately or by untrained personnel. Everyone involved with siting,
starting up, operating or repairing a load cell must have read and understood
the mounting instructions and in particular the technical safety instructions.
Load cells may be damaged or destroyed by improper use or non-compliance
with the mounting and operating manual, these safety instructions or any other
applicable safety regulations (safety and accident prevention regulations of
employers’ liability insurance associations) when handling the load cells. Load
cells can break, particularly if overloaded. The breakage of a load cell can also
cause damage to property or injury to persons in the vicinity of the load cell.
If load cells are not used according to their designated use, or if the safety
instructions or specifications in the mounting and operating manual are
ignored, it is also possible that the load cells may fail or malfunction, with the
result that persons or property may be affected (due to the loads acting on or
being monitored by the load cells).

Safety instructions
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The scope of supply and performance of the transducer covers only a small
area of weighing technology, as measurements with (resistive) strain gage
sensors presuppose the use of electronic signal conditioning. In addition,
equipment planners, installers and operators should plan, implement and
respond to the safety engineering considerations of the weighing 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
without our express permission. Any modification shall exclude all liability on
our part for any damage resulting therefrom.
Resale
If the load cell is resold, these mounting instructions must be included with the
load cell.
Environmental protection, disposal
In accordance with national and local environmental protection, material
recovery and recycling regulations, old transducers that are no longer
serviceable must be disposed of separately from normal household waste.
If you require more information about disposal, please contact your local
authorities or the dealer from whom you purchased the product.

Safety instructions
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Qualified personnel
Qualified personnel means persons entrusted with installing, mounting, starting
up and operating the product, who possess the appropriate qualifications for
their function.
This includes people who meet at least one of the three following criteria:
1. Knowledge of the safety concepts of automation technology is a require
ment and as project personnel, you must be familiar with these concepts.
2. As 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.
3. As commissioning engineers or service engineers, you have successfully
completed the training to repair the automation systems. You are also
authorized to operate, ground and mark circuits and equipment in
accordance with safety engineering standards.

Markings used
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2 Markings used
2.1 Markings used in this document
Important instructions for your safety are highlighted. Following these
instructions is essential in order to prevent accidents and damage to property.
Symbol Meaning
Note This marking draws your attention to a situation in
which failure to comply with safety requirements
could lead to property damage.
Important
This marking draws your attention to important
information about the product or about handling the
product.
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 sections of the manual,
diagrams, or external documents and files.
2.2 Symbols on the device
CE mark
With the CE mark, the manufacturer guarantees that the
product complies with the requirements of the relevant
EC directives (the Declaration of Conformity can be
found on the HBM website HBM (www.hbm.com) under
HBMdoc).
Statutory waste disposal marking
In accordance with national and local environmental
protection and material recovery and recycling
regulations, old devices that can no longer be used must
be disposed of separately and not with normal household
garbage. If you need more information about disposal,
please contact your local authorities or the dealer from
whom you purchased the product.

Application
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3 Application
RTN ring torsion load cells are available in different variants for a wide range of
maximum capacities (1 to 470 metric tons). They are suitable for weighing all
kinds of containers and for large platform scales. They have a stainless steel
body that lends them a high IP rating and makes them suitable for use in harsh
conditions. With their annular strain gage, RTN load cells considerably
minimize the influence of transverse and lateral loads. A legal-for-trade
weighing system up to 3,000 parts (as per OIML R60) is possible.

Mounting instructions
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4 Mounting instructions
When mounting the load cells, pay attention to the following:
SPlease handle load cells with care!
SLoad cells are precision sensors and so their achievable accuracy depends
greatly on their being mounted correctly!
SUse suitable hoisting gear for mounting the weighing device!
SDo not overload load cells even briefly (e.g. due to unevenly distributed
support loads)!
SWhen carrying out adjustment work that could endanger the load cells, use
supports (dummies) of equal height!
SThe load must be introduced concentrically to the load application surface
and in the measurement direction of the load cell. Use convex thrust pieces
with sufficiently large radii (HBM accessory).
SAvoid lateral forces and torques (also see the “Specifications” section)!
SDepending on the construction, use anti-liftoff devices and limit stops if
necessary!
SEnsure the force application points of the load cells are all on the same
level. The mounting accessories include shims for this purpose
(see section 9)!
SProtect load cells against
- one-sided heat radiation
- the effects of subsequent welding work1)
- strong temperature variations!
STo prevent rapid wear, grease the force application part. Please take care
not to use too much grease, as this will cause the rubber ring of the cell to
stick (from maximum capacity >4.7 t)!
1) Every load cell should be bridged with a twisted copper cable (e.g. EEK... from HBM = approx.
16 mm2) during or immediately after installation. This prevents damage due to welding currents.
Grounding the load cell reduces the risk of it sustaining damage due to lightning strikes.

Mounting instructions
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SThe optional cable with outer braided wire sheath is intended for use when
there is increased mechanical stress (e.g. damage caused by gnawing
rodents). If this cable is used, the outer braided wire is connected to
potential equalization at least once, to avoid accidental energization. This
outer braided wire is not used to shield the load cell. Instead, the inner
braided wire of the load cell cable (also see section 5.5 “EMC protection”,
page 15) is used for shielding.
Notice
Load cells are precision measuring elements and need to be handled carefully.
Dropping or knocking the transducer may cause permanent damage. Make
sure that the transducer cannot be overloaded, including while it is being
mounted.
Preparations for mounting
SThe installation space or foundations must be level and horizontal.
SThe base plate of the load cell has to satisfy certain special requirements:
Thermal expansion coefficient of 11·10-6/K; flatness less than 0.05 mm;
roughness Ra 3.2; hardness more than 40 HRC.
SFor correct function, always use the original HBM base plate. This is
included with the VEN and VPN installation accessory from HBM.
Mechanical sources of error
Lateral forces
SLoad acts on the load cell from other directions than the measurement
direction, due to incorrect mounting or insufficient bending stiffness of the
construction.
During operation, lateral forces may occur in the following conditions:
1. Braking forces of a vehicle on a weighbridge
2. Deflections in the construction
3. Expansion in the construction due to raised temperatures

Mounting instructions
RTN A01153_03_Y00_01 HBM: public 11
4. Wind forces when installed outdoors
5. Drive motors/mixers
If the lateral forces remain below the values specified in the data sheet,
measurement errors may occur but the load cell will not suffer any lasting
damage.
If there is a risk that the permissible lateral forces may be exceeded, suitable
measures such as stay rods or buffers must be provided.
If the load cell is subjected to normal force, greater lateral forces dependent on
the normal force may be transferred due to base plate friction.
If high lateral forces can be expected in your application, we recommend the
use of pendulum bearings from HBM to minimize the lateral forces dependent
on the normal force that acts on the load cell.
Also see section 1 “Safety instructions” on page 3.

Electrical connection
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5 Electrical connection
The following can be connected for measurement signal conditioning:
SCarrier-frequency amplifiers
SDC voltage amplifiers
that are designed for strain gage measurement systems.
If rubber-metal bearings are used, the construction is insulated against the
foundation. Here, please pay attention to DIN/VDE 0100, Part 410 as regards
the necessary potential equalization.
5.1 Connection in a 4-wire configuration
(red)
(black)
(blue)
(white)
Bridge excitation voltage (-)
Bridge excitation voltage (+)
Signal (+)
Signal (-)
Sensing element (+)
Sensing element (-)
Extension cable
(6-wire configuration)
Load cell RTN…
(4-wire configuration)
(yellow) Shield
Measuring amplifier/weighing
electronics
(6-wire configuration)
Fig. 5.1 Cable assignment of RTN...
Electrical and magnetic fields often induce interference voltages in the
measuring circuit (also see section 5.5 “EMC protection”).
Notice
Do not open the screwed cable gland on the load cell under any
circumstances; if it is opened inadvertently, the load cell must be sent to the
factory for repair.

Electrical connection
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5.2 Plug connection (optional)
Plug-in contact 1 = measurement signal (-)
Plug-in contact 6 = excitation voltage (+)
Plug-in contact 5 = sense lead (+)
Plug-in contact 7 = excitation voltage (-)
Plug-in contact 3 = sense lead (-)
Plug-in contact 8 = measurement signal (+)
2
3
4
5
6
7
1
8
Plug-in contact 2 = not in use
Plug-in contact 4 = not in use
Fig. 5.2 Connector pin assignment
With this connector pin assignment, the output voltage at the measuring
amplifier is positive when the transducer is loaded. The plug is implemented in
a 6-wire configuration.
When transducers in a 6-wire configuration are connected to amplifiers in a
4-wire configuration, the sense leads of the transducers must be connected to
the corresponding excitation voltage leads: Marking (+) with (+) and marking (-)
with (-), see Fig. 5.2. This measure also reduces the cable resistance of the
excitation voltage leads.
However, there will be a voltage loss on the supply leads due to the cable
resistance that is still present and not compensated for by the 6-wire
configuration. A large part of this loss can be eliminated by a calibration,
however, the temperature-dependent part remains. The pin assignment for the
cables available as accessories can be found in data sheet B03643.

Electrical connection
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5.3 Parallel connection of several transducers
Only load cells with an aligned output (nominal (rated) sensitivity and output
resistance) are suitable for parallel connection. Wire load cells in parallel by
joining together the cable terminations of the same color.
Important
In this case, if an individual load cell is overloaded, this will not be apparent
from the output signal.
(red)
(black)
(blue)
(white)
Bridge excitation voltage (-)
Bridge excitation voltage (+)
Signal (-)
Signal (+)
Sensing element (+)
Sensing element (-)
Extension cable
Junction box (e.g. “VKK...” or “VKEX” from HBM)
(yellow) Shield
Measuring amplifier Weighing electronics
Fig. 5.3 Parallel connection of several transducers
5.4 Shortening and extending the cable
Use only shielded, low-capacitance measurement cables for extending the
cable, making sure there is a proper connection with minimal contact
resistance.
To achieve full accuracy, a 6-wire configuration should be used to extend the
cable all the way to the subsequent electronics.
A 4-wire configuration is used for the load cells and the cable must not be
shortened.

Electrical connection
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5.5 EMC protection
Electrical and magnetic fields often induce interference voltages in the
measuring circuit. To ensure reliable measurement, however, the transducer
must be able to transmit signal differences of less than 1 µV to the analysis
unit without interference.
Planning the shielding design
Due to the numerous application options and differing local constraints, we can
only provide you with general information on correct connection. The shielding
design suitable for your application must be planned locally by an appropriate
specialist.
HBM load cells with shielded round cables are EMC-tested in accordance with
EU directives and bear the CE mark.
Voltage surges as per EN 61000-4-5 can give rise to deviations from the load
cell’s specified accuracy. These deviations can be up to 0.05 %, based on the
full scale value. These surges in plants are caused by lightning strikes or
switching operations in power circuits. This is particularly evident with cables
over 30 m long or if the equipment is used outdoors. Customers should take
additional precautions in these cases.
Please note:
SConnect the whole surface of the connection cable shield to the shielding
housing of the electronics. If using several load cells, connect the shields to
the whole surface of the junction box (grouping of transducer signals, e.g.
type VKK2 from HBM). From there, connect the measurement cable for the
electronics to the whole surface of the junction box and the whole surface of
the shielding electronics housing.
SThe connecting cable shield must not be used for discharging potential
differences within the system. You must therefore lay sufficiently
dimensioned potential equalization lines to compensate for possible
potential differences.
Important
Potential equalization is specified for applications in potentially explosive
atmospheres.

Electrical connection
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SUse only shielded, low-capacitance measurement cables (HBM cables fulfill
both conditions).
SDo not route measurement cables parallel to power cables, particularly
power lines or control circuits. If this is unavoidable, protect the
measurement cables with steel conduits, for example.
SAvoid stray fields from transformers, motors and contact switches.

Corrosion protection and maintenance
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6 Corrosion protection and maintenance
Protect load cells against chemicals that could attack the cable or the steel of
the housing.
Notice
Acids and all substances that release ions also attack stainless steels and their
weld seams.
The resulting corrosion could cause the transducer to fail. If this is the case,
you must provide appropriate means of protection.
The transducer is basically maintenance free.
Dust, dirt and other foreign matter must not be allowed to accumulate
sufficiently to divert some of the measuring force onto the housing, thus
distorting the measured value (force shunt).
Do not use hard or pointed objects to clean the transducer. The transducer
achieves an IP rating of IP68 (test conditions: 100 hours under 1 m water
column) or, optionally, IP69K (water at high pressure, steam cleaning), as per
DIN EN 60529. The transducer is therefore suitable for wet cleaning. Despite
this, the transducer should be protected against the long-term effects of
moisture.

Specifications
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7 Specifications
Information
You can find further product information at www.hbm.com/rtn