Siemens SIWAREX R User manual

s
SIWAREX R
Mounting units for SB series
Operating Instructions Revision 09/2004

Document No.: A5E00353789B Page 2
s
SIWAREX R
Mounting elements for load cells in the SB series
Operating Instructions
Chapter Overview
Warning and Safety Terms ................................................................................. 4
General ............................................................................................................... 5
1. General Conditions for Installation and Assembly ................................ 7
1.1 Lift-off Protection.......................................................................................7
1.2 Overload Protection ...................................................................................7
1.3 Guidings.....................................................................................................8
1.4 Load-cell Dummies...................................................................................10
1.5 Load Cell Handling ...................................................................................10
1.6 Welding and Installation Work .................................................................11
1.7 Mounting .................................................................................................11
1.8 Installation Surfaces.................................................................................12
1.9 Dismantling..............................................................................................13
1.10 Explosion Protection ................................................................................13
2Elastomer Bearing .................................................................................. 14
2.1 Technical Description...............................................................................14
2.1.1 Application Range........................................................................................ 14
2.1.2 Construction ................................................................................................. 14
2.2 Assembly..................................................................................................15
2.3 Technical Data .........................................................................................18
2.3.1 Function Data............................................................................................... 18
2.3.2 Dimensions ................................................................................................... 19
2.4 Care and Maintenance .............................................................................20
2.5 Ordering Data............................................................................................... 21
3Combination Mounting Unit ................................................................. 22
3.1 Technical Description...............................................................................22

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3.1.1 Application Range........................................................................................ 22
3.1.2 Construction ................................................................................................. 22
3.2 Assembly..................................................................................................23
3.3 Technical Data .........................................................................................28
3.3.1 Function Data............................................................................................... 28
3.3.2 Dimensions ................................................................................................... 29
3.4 Care and Maintenance .............................................................................30
3.5 Ordering Data ..........................................................................................30
4Guiding for Combination Mounting Unit ............................................. 31
4.1 Technical Description...............................................................................31
4.1.1. Application Range........................................................................................ 31
4.1.2 Construction ................................................................................................. 32
4.2 Assembly..................................................................................................33
4.3 Technical Data .........................................................................................34
4.3.1 Function Data............................................................................................... 34
4.3.2 Dimensions ................................................................................................... 35
4.4 Care and Maintenance .............................................................................35
4.5 Ordering Data ..........................................................................................36
5Grounding Cable .................................................................................... 37
5.1 Technical Description...............................................................................37
5.1.1. Area of Application ...................................................................................... 37
5.1.2 Structure ....................................................................................................... 37
5.2 Mounting .................................................................................................37
5.3 Dimensions ..............................................................................................38
5.4 Care and Maintenance .............................................................................38
5.5 Ordering Data ..........................................................................................38

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Warning and Safety Terms
DANGER
means, that death, severe injury to persons or damage to equipment can be
caused, if the respective safety measures have not been taken.
WARNING
means, that death or severe injury can be caused, if the respective safety
measures are not taken.
CAUTION
with a warning triangle means that failure to take the necessary precautions may
lead to minor injury.
CAUTION
without a warning triangle means that failure to take the necessary precautions
may lead to property damage.
IMPORTANT
Means that failure to observe the appropriate instructions may lead to an
undesirable result or condition.
NOTE
means a notice concerning possible advantages of conforming with the
recommendation.
Copyright © Siemens AG 2004 All rights reserved
Circulation or duplication of this document, utilization and
disclosure of its contents are not permitted unless explicitly
approved. Violations will be liable to claims for damages. All rights
reserved especially in the event of a patent award or utility model
registration.
Siemens AG
Automation and Drives
Process Instrumentation and Analytics
D-76181 Karlsruhe
Disclaimer
We have tested the contents of this document for compatibility
with the hardware and software described. This does not exclude
the possibility of discrepancies, in which case we do not guarantee
the complete compatibility of this document. The information in
this document is assessed regularly and any necessary corrections
are included in the next revision. We are grateful for any
suggestions for improvement.
© Siemens AG 2004
Subject to technical changes.

Document No.: A5E00353789B Page 5
General
Please read this manual before starting work! It contains important notes and data
for ensuring the general safety and functionality of this device. This information will
simplify the utilization of this product and will lead to more precise and secure
measurement results.
Intended Utilization
Intended utilization means that this product is only to be utilized within the
limitations defined in the technical specifications and purposes of use in this
operating manual.
There are no dangers associated with this device when conforming with the safety
notes and the intended utilization.
The fail-safe and secure operation of this device depends on proper transportation,
storage, installation and assembly as well as on careful operation and
commissioning.
Proper operation of this device can only be ensured if the specifications provided in
technical data are observed.
Improper handling can cause death, bodily harm and damage to equipment.
Notes on Product Liability
We expressly point out that the nature of the product is described exclusively and
conclusively in the sales contract. The contents of this product documentation are
not part of an earlier or existing agreement, acceptance or legal relationship nor do
they affect these in any way. All obligations of Siemens result from the sales
contract, which also contains the full and solely valid liability agreement. The
provisions concerning product liability specified in the sales contract are not
extended or limited by the information provided in this document.
Delivery Notes
The respective scope of delivery is listed on the enclosed shipping documents
according to the valid contract of sale.
Please follow the instructions for opening the packaging. Check the delivery for
completeness and damage. In particular, compare the order number on the type
plate with the order data.
Qualified Personnel
Qualified personnel, in regards to the safety-related information in this manual and
the product itself, are persons who are familiar with the installation, assembly,
commissioning and operation of this product. They must be authorized and
qualified to install, put into operation and maintain devices, systems and circuits in
accordance with national safety rules and regulations.

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Brand names / Trademarks
SIWAREX ® is a registered trademark of Siemens AG.
The other designations in this manual may be trade marks, which if used by third
parties, may infringe upon the rights of the proprietor.

Document No.: A5E00353789B Page 7
1. General Conditions for Installation and Assembly
1.1 Lift-off Protection
Lift-off protections prevent the top plates being lifted from the load cells or
permanently mounted load cells from being overloaded by tension against the
measuring direction. Lift-off protections are necessary if there is a danger of the
load platform being lifted or tipped. This is possible with light high containers or
with silos that are not affixed for example.
Lift-off protections are integrated in the
combination mounting units of the SB
series. When using the mounting units,
the lift-off protections should be
planned constructively. A suggestion for
an effective solution is shown in Fig. 1-
1. The measurement X indicates the
possible lift-path of the load platform.
The drill hole ØD must be larger than
the bolt diameter Ød. The movement of
the load platform may not be hindered.
1.2 Overload Protection
Overload protection means protecting load cells from loads in the direction of
measurement that are too great. Forces that exceed the load limits for the load cells
can also come from the side.
Overload protection in the direction of measurement
Load cells are normally protected against vertical overloading by placing a stop-bolt
under the transmission of force. The path of measurement for the load cell is
limited in this manner. On load cells with high rated loads, the danger of accidental
overloading is not so great. Any possible excessive loading can be taken into
account while dimensioning the load cells.
Another way of protecting load cells from overloading is in over-dimensioning the
load cells.
Overload protection from the side
Transverse force are produced, for example, by wind, filling processes, acceleration
or conveyor belt friction. If these forces exceed certain values, the load cells must
be protected from them.
The weight force is transferred to the load cells via elastomer bearings or pendulum
bolts in the SB cells. These elements allow a certain amount of sideways movement
of the load platform or a change in length due to thermal expansion. They generate
a responsive force which centers the load platform position again corresponding
with the occurring movement. This freedom of movement is expressly wished and
necessary for exact weighing. If the restoring force is so high that the return force is
overcome by pendulum bolts or elastomer bearings up to the deflection limit,
appropriate safety measures must be taken. These could be oscillation limitations or
guidings (see chapter 1.3). Oscillation limitations must be constructed or set so that
Fig 1-1 Lift-off protection
solution suggestion

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the permitted movement, on all sides, cannot be exceeded. In Fig. 1-2, this is
displayed in two examples.
Load cells of the SB series have oscillation limitations integrated in them with the
combination mounting units.
CAUTION
When using weighing cells with low rated loads, overload protection are to be
used, cross-directional as well, in order to protect the cells from damage.
The use of load cells above the maximum working load or the maximum lateral
load can lead to irreparable faults or damage to the load cells or the mounting unit.
1.3 Guidings
Guidings compensate for cross-forces immediately. They allow no sideways
movement of the load platform. At the same time, they cannot change shape when
distances change in the support points (e.g. thermal expansion). Guiding
positioning is shown in Fig. 1-3. They are used if the weight must be determined
under the influence of a transverse force.
Guidings must be constructed perpendicular to the effective direction of the load
cells so that there are no force components in the direction of measurement.
Stretching the guidings is best avoided when they are positioned with the same
direction of rotation. To fasten a loading platform or a hopper in a static position,
three guidings will suffice. With four guidings, there is a danger of these putting
force on each other and that this could cause weighing errors. If four guidings are
used anyway, they should be installed with enough play to compensate.
±2.8
±4
2.8
±4
±4
4
Limit stop
Drill hole
Bolt
PlatformPlatform
±2.8
±4
2.8
±2.8
±4
2.8
±4
±4
4
Limit stop
Drill hole
Bolt
PlatformPlatform
Oscillation limitations at a permitted oscillation of 4 mm in a dual weighing
p
latform exam
p
le.
Fig. 1-2 Oscillation limitation example

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The guidings should correspond with the principles used in the weighing
technology. Round-head bolt guides for up to 1000 kN lateral load are also available
upon request.
Fig. 1-3 Guiding positioning

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1.4 Load-cell Dummies
Load cells are sensitive sensors. To protect them from damage, they should only be
handled as late as possible for installation and transport. During installation and
transport, these should be replaced by dummies or phantoms. Dummies can be
constructed as follows for example:
1. A replica of the mounting element using a welded construction.
A pipe or any other steel profile can be welded between two plates with the
respective hole format for the fastening bolts. The total height corresponds
to the mounting height of the mounting element. That is the most stable
and safe version. Rough mounting work can be performed.
2. Using a SIWAREX R combination mounting unit.
The combination mounting units are supplied as completely assembled
units. The units are set at the approximate installation height for an
operational unit. Slight adjustments can be made during the installation.
1.5 Load Cell Handling
DANGER
Load cells and mounting units are not machine elements that are constructed
using standard safety factors. It is therefore absolutely necessary to prepare for the
potential danger with respective supports or other means of protection.
CAUTION
To protect against undesirable electrical current, such as static discharge that can
occur during welding or which can be caused by lighting for example, the load
cells should be bridged with highly flexible grounding cables
(e.g. SIWAREX R grounding cable 7MH3 701-1AA1).
SIWAREX R load cells may only be installed and connected by qualified personnel.
Load cells are precision components and are to be handled carefully. Pay special
attention during transport and assembly.
CAUTION
Mechanical jolts or dropping could irreparably damage the load cells.
Load cells are not to be carried by their connecting cables.

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Loads must be introduced precisely in the direction of measurement of the load
cells. Torsion and bending moments, excentric loading and lateral loads are
disturbance forces that lead to incorrect measurements and can cause damage if
exceeding the permitted limitations of the load cells and mounting elements.
The mounting components allow enough play in movement that thermal expansion
does not lead to lateral loading.
1.6 Welding and Installation Work
As long as installation work is not complete on the scale, the load cells should be
replaced with dummies to protect them from jolts or welding current.
CAUTION
If welding is required after installing the load cells, make absolutely sure that the
welding current is not routed through the load cells. The ground clamp of the
welder is to be securely connected in the direct vicinity of the point to be welded.
The load cells must be bridged with a grounding cable. The individual load cells are
to be disconnected. The free cable ends should be insulated.
1.7 Mounting
Load cells are never to be overloaded. Slowly put the load platform on. Especially
with load cells having lower rated loads, there is a danger that external forces
during installation, e.g. tightening counter nuts, will bend the load cell bodies.
WARNING
Proper tools are to be used for lifting the load platform. Ensure that the respective
safety regulations are followed.
NOTE
Molded brackets or eyebolts should exist on the loading platform for the proper
utilization of lifting instruments.
If overload security mechanisms are available, set them up so that the desire load
can be taken on safely. They must permit an unrestricted increase in weight up to
the set weight.
The gap between the load cell and the overload protection is to be guarded from
contamination and icing.
Overload protection is to be checked regularly during maintenance work for easy
adjustment.

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DANGER
Contaminated, icy or incorrectly set overload protection will create blockages
which cause incorrect measurements or can cause injury or damage to the
machinery by overloading the scale.
CAUTION
Proper assembly and installation of load cells and mounting elements is to be
ensured by checking the assembly dimensions and freedom of movement for
example. Incorrect assembly can cause damage to load cells and mounting
elements.
Ensure that the cable is not damaged, disconnected or separated.
Wrap and hang the cable in a loop hanging down on vertical cable mounts to
divert any moisture away from connections.
1.8 Installation Surfaces
The following conditions are to be met for mounting element installation surfaces:
• The position and slope deviation of the installation surfaces to one-another
should correspond with the general tolerances for welded constructions,
EN ISO 13920.
• The foundation must be absolutely solid and unable to sink. Level steel
plates should be cast in cement foundations upon which the mounting
elements are mounted.
• The anchorage points must be perpendicular to the direction of
measurement and should preferably all be at the same level.
If there are more than three mounting points, then the suspension is normally
statically indeterminate. It is inevitable that the load will not be evenly distributed
over all load cells on a stiff foundation with stiff loading platforms. Two diagonally
positioned load cells support the main load. The other cells merely support the load
platform. There are two ways to consider this:
1. By over-dimensioning the load cells
The rated load of the load cells is calculated so that the overall weight can be
supported on two load cells using four mounting points for example.
This will also prevent load cell overloading if there is a possibility of the foundation
sinking.

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2. Mounting point height adjustment
The output signals of all load cells are determined one after the other when they
are loaded. In order to achieve similar load on all of them, spacer plates are used to
adjust the height. The spacer plates are pushed in between the brackets and the top
plate of the mounting element for the best results.
The output signals of the individual load cells correspond to load distribution.
Proceed as follows to measure the output signals:
Disconnect load cell lines SIG+ and SIG-.
• Supply the load cells with the supply voltage (e.g. 10.2V).
• Measure the output voltage between SIG+ and SIG- on each individual load
cell.
• Now put spacer plates under the brackets for the load cell with the lowest
value until the output voltages match.
The load cell seat must be horizontal, level over the full-coverage and like the load
cell underside, absolutely clean.
The contact surface that introduces the force is to be coated with high-performance
grease.
1.9 Dismantling
When dismantling the load cells, the same safety and security measures are to be
followed as for the installation and assembly.
• All power supply lines are to be switched off.
• Secure the load platform from falling.
• User appropriate lifting mechanisms and tools.
• Take all load off of the load cells and carefully remove them without any
excessive force (no jolting movements).
• Do not cut the cable if the load cells are to be used again or if being sent in
for repair.
• To not step on or pull on the cable for moving the load cells.
1.10 Explosion Protection
There is no danger of explosion caused by the mounting elements of the load cells
and therefore they are not subject to the EC Directive 94/9 EG (ATEX).

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2 Elastomer Bearing
2.1 Technical Description
2.1.1 Application Range
The elastomer bearing is used for protecting the load cells if there is the possibility of
having to deal with jolts or oscillation.
It has a self-centering effect on the load platform. Together with the base plate it offers a
simple solution for load cell mounting. The elastomer bearing is firmly connected to the
load cell and the load platform. It also provides limited lifting security.
2.1.2 Construction
A complete elastomer bearing unit consists of basic order-components base plate with
overload protection, load cell and elastomer bearing.
The base plate (1) is bolted to the foundation with four bolts. The load cell (3) is fastened
to the base plate (1) with two hexagon bolts (5) and the spacer bar (2). The elastomer
bearing (10) is affixed to the load cell (3) with a hexagon bolt (8). The elastomer bearing
(10) is bolted to the load platform. The load platform is centered with the elastomer
bearing (10) this way. Transverse movement of the load platform is permitted to a certain
degree.
The measurement path of the load cell (3) is limited by the adjustable overload protection
mechanism (7). This protects from accidental damage caused by overloading.
The elastomer bearing (10) is a rubber-metal combination made of neoprene and stainless
steel.
(Numbering, see fig. 2-1)

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2.2 Assembly
The conditions for installation are very different. The load platform can be very low or
relatively high. It could be a hopper, a platform or a conveyor for example. The following
assembly instructions can only be taken as general guidelines.
WARNING
Proper tools are to be used for lifting the load platform. Ensure that the respective
safety regulations are followed.
The load platform should always be built on dummies to begin with, so that the load cells
are protected from damages during assembly. The load platform must then only be lifted
a few millimeters from bracket to bracket to position the elastomer bearing. The following
description of assembly procedures is based on this situation.
Assembly procedure: (numbering see Fig. 2-2)
1. Load cell preparation:
• A data sheet is supplied with every load cell with the calibration values for that
load cell. This is found in a supply pocket which is stuck on the packaging. Take
the data sheet and store it in a safe place.
• Unpack the load cell.
No. Designation No. Designation
1 Base plate 6 Nut
2 Spacer bar 7 Overload protection
3 Load cell 8 Hexagon head screw
4 Washer 9 Washer
5 Hexagon head screw 10 Elastomer bearing
Fig. 2-1 Structure of elastomer bearing

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2. Base plate preparation:
• Unpack the base plate.
3. Elastomer bearing preparation:
• Unpack the elastomer bearing (10).
4. Assemble the elastomer bearing unit:
NOTE
Please follow the guidelines from chapter 1.5 Load Cell Handling when working
with load cells.
CAUTION
An incorrect or incomplete assembly can result in damaging load cells, mounting
components and the loading platform.
DANGER
A falling loading platform can result in death, severe injury or damage to
equipment depending on exposure.
• Bolt the elastomer bearing (10) to the load cell (3) with the hexagon bolt (8) and
the washer (9). Hold the elastomer bearing (10) down when tightening the
hexagon bolt (8) to prevent damage being done to the load cell. The arrow on the
front of the load cell indicates the direction of measurement.
• Lie the spacer bar (2) on the base plate (1) so that both holes are aligned with the
threaded holes in the base plate (1) and so that it is even. The spacer bar (2) is
asymmetrical.
• Put the load cell (3) on the spacer bar (2) using 2x hexagon bolts (5) and 2x
washers (4).
• Tighten 2x hexagon bolts (5) with 110 Nm ( 0,5 t, 1 t, 2 t), or 540 Nm (5 t). Do
not use the load cell as leverage when tightening the bolts as this can cause
damage to the load cell.
5. Install the elastomer bearing unit:
• Loosen the bolts on the dummies
• Lift the loading platform from the first bracket and remove the dummy.
• Install the elastomer bearing unit and screw the bolts in loosely.
• Align mounting holes of the elastomer bearing (10) if necessary.
• Slowly lower the loading platform.
• Install the remaining elastomer bearing units as described.
• Ensure that the elastomer bearings are not under tension.
• Tighten the fastening bolts.

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Fig. 2-2 Mounting the elastomer bearing

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6. Setting the overload protection:
• Load the loading platform with the
maximum applicable load.
• Set the overload protection
mechanism (7) in connection with the
nut (6) to 0.05 - 0,1 mm, see
dimension X in Fig. 2-3
• Dimension X must exist after
tightening the nut (6) as well.
DANGER
Contaminated, icy or incorrectly set overload protection will create blockages
which cause incorrect measurements or can cause injury or damage to the
machinery by overloading the scale.
2.3 Technical Data
2.3.1 Function Data
Rated load 0.5 t - 5 t
Permitted transverse movement ± 4 mm
Fig. 2-3 Setting the overload
p
rotection

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2.3.2 Dimensions
Fig. 2-4 Dimensions elastomer bearing
Rated load A B C E F G H J K L M
0.5 t, 1 t 200 100 170 11 85 156 92,6 100 75 11 231
2 t 200 100 170 11 100 156 92,6 120 90 11 241
5 t 235 120 205 14 100 184 109,9 120 90 11 271

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2.4 Care and Maintenance
General
The physical properties of most rubber goods will change in adverse conditions or if
improperly handled. Rubber components can become unusable when it becomes too soft
or too hard, gets deformed or cracks, peels or has any other surface damage. The changes
can be caused by the effects of e.g. ozone, heat, light, humidity, solvent or long periods of
tension.
If properly handled and stored, rubber products will retain the effective properties over a
long period of time (several years).
Service life and Inspections
The service life of elastomer components depends on the type and the load.
Rubber undergoes a natural aging process.
With loads that are within the permitted range, a service life of over 6 years can be
expected.
The rubber-metal components are maintenance-free during operation. The round surface
of the pendulum bolt is to be greased if necessary.
A visual inspection of the components should be performed 6 months after installation
and once per year thereafter. Checking the bond between the rubber and metal can be
done using a manual mechanical bond test. This is done by pressing the rubber back with
a blunt "test-iron" (pressure ridge with arc).
If portions of the rubber surface are coming apart in the bonding zone between the
elastomer and the metal or if surface cracks appear in the individual elastomer layers,
observe those areas (in intervals).
Replacement
A replacement is necessary if:
• only 70% of the initial rubber thickness is achieved through setting and loading,
• if the weather has caused visible cracking over cm2rubber surface,
• the item is excessively swollen due to undue oil seepage,
• the rubber-metal bond is breaking down,
• mechanical damage resulting from the sensitivity of the rubber leading to further
damage to the product is present.
Cleaning
Cleaning solutions with a neutral pH value are recommended and covalent cleaning
solvents such as gasoline for example are not to be used under any circumstances.
Components should be rinsed with water after cleaning in certain cases. Otherwise the
rubber-metal bond is to be protected from cleaning solvents using constructive means.
The use of sharp objects, wire brushes or sandpaper is not permitted. The flat seal may not
be exposed directly to a water jet. The round surface of the pendulum bolt is to be re-
greased when necessary.
The overload protection mechanism is to be checked for any contamination.