Beckhoff EP3356-0022 Operator's manual

Documentation | EN
EP3356-0022
1-channel precise load cell analysis (resistor bridge), 24 bit
2020-09-22 | Version: 1.4

Table of contents
EP3356-0022 3Version: 1.4
Table of contents
1 Foreword ....................................................................................................................................................5
1.1 Notes on the documentation..............................................................................................................5
1.2 Safety instructions .............................................................................................................................6
1.3 Documentation issue status ..............................................................................................................7
2 Product overview.......................................................................................................................................8
2.1 EP3356-0022 - Introduction...............................................................................................................8
2.2 EP3356-0022 - Technical data ..........................................................................................................9
2.2.1 Additional checks............................................................................................................. 10
2.3 Scope of supply ...............................................................................................................................10
3 Basic principles of strain gauge technology ........................................................................................11
4 Mounting and Cabling.............................................................................................................................18
4.1 Mounting..........................................................................................................................................18
4.1.1 Dimensions ...................................................................................................................... 18
4.1.2 Fixing ............................................................................................................................... 19
4.1.3 Tightening torques for plug connectors ........................................................................... 19
4.1.4 Functional earth (FE) ....................................................................................................... 19
4.2 EtherCAT.........................................................................................................................................20
4.2.1 Connectors ...................................................................................................................... 20
4.2.2 Status LEDs..................................................................................................................... 21
4.2.3 Cables.............................................................................................................................. 21
4.3 Supply voltages ...............................................................................................................................22
4.3.1 Connectors ...................................................................................................................... 22
4.3.2 Status LEDs..................................................................................................................... 23
4.3.3 Conductor losses ............................................................................................................. 23
4.4 Resistor bridge ................................................................................................................................24
4.5 UL Requirements.............................................................................................................................26
5 Commissioning/Configuration ...............................................................................................................27
5.1 Integration in TwinCAT ....................................................................................................................27
5.2 EtherCAT slave process data settings (PDO) .................................................................................28
5.3 Basic function principles ..................................................................................................................30
5.4 Application notes .............................................................................................................................39
5.5 Calibration and adjustment..............................................................................................................42
5.6 Notices on analog specifications .....................................................................................................46
5.7 Voltage measurement .....................................................................................................................51
5.8 Distributed Clocks mode..................................................................................................................53
5.9 Process data....................................................................................................................................54
5.10 Object description and parameterization .........................................................................................62
5.11 Example program ............................................................................................................................75
5.12 Restoring the delivery state .............................................................................................................80
6 Appendix ..................................................................................................................................................81
6.1 General operating conditions...........................................................................................................81
6.2 Accessories .....................................................................................................................................82
6.3 Version identification of EtherCAT devices .....................................................................................83

Table of contents
EP3356-00224 Version: 1.4
6.3.1 Beckhoff Identification Code (BIC)................................................................................... 87
6.4 Support and Service ........................................................................................................................89

Foreword
EP3356-0022 5Version: 1.4
1 Foreword
1.1 Notes on the documentation
Intended audience
This description is only intended for the use of trained specialists in control and automation engineering who
are familiar with the applicable national standards.
It is essential that the documentation and the following notes and explanations are followed when installing
and commissioning these components.
It is the duty of the technical personnel to use the documentation published at the respective time of each
installation and commissioning.
The responsible staff must ensure that the application or use of the products described satisfy all the
requirements for safety, including all the relevant laws, regulations, guidelines and standards.
Disclaimer
The documentation has been prepared with care. The products described are, however, constantly under
development.
We reserve the right to revise and change the documentation at any time and without prior announcement.
No claims for the modification of products that have already been supplied may be made on the basis of the
data, diagrams and descriptions in this documentation.
Trademarks
Beckhoff®, TwinCAT®, EtherCAT®, EtherCATG®, EtherCATG10®, EtherCATP®, SafetyoverEtherCAT®,
TwinSAFE®, XFC®, XTS® and XPlanar® are registered trademarks of and licensed by Beckhoff Automation
GmbH. Other designations used in this publication may be trademarks whose use by third parties for their
own purposes could violate the rights of the owners.
Patent Pending
The EtherCAT Technology is covered, including but not limited to the following patent applications and
patents: EP1590927, EP1789857, EP1456722, EP2137893, DE102015105702 with corresponding
applications or registrations in various other countries.
EtherCAT® is registered trademark and patented technology, licensed by Beckhoff Automation GmbH,
Germany.
Copyright
© Beckhoff Automation GmbH & Co. KG, Germany.
The reproduction, distribution and utilization of this document as well as the communication of its contents to
others without express authorization are prohibited.
Offenders will be held liable for the payment of damages. All rights reserved in the event of the grant of a
patent, utility model or design.

Foreword
EP3356-00226 Version: 1.4
1.2 Safety instructions
Safety regulations
Please note the following safety instructions and explanations!
Product-specific safety instructions can be found on following pages or in the areas mounting, wiring,
commissioning etc.
Exclusion of liability
All the components are supplied in particular hardware and software configurations appropriate for the
application. Modifications to hardware or software configurations other than those described in the
documentation are not permitted, and nullify the liability of Beckhoff Automation GmbH & Co. KG.
Personnel qualification
This description is only intended for trained specialists in control, automation and drive engineering who are
familiar with the applicable national standards.
Description of instructions
In this documentation the following instructions are used.
These instructions must be read carefully and followed without fail!
DANGER
Serious risk of injury!
Failure to follow this safety instruction directly endangers the life and health of persons.
WARNING
Risk of injury!
Failure to follow this safety instruction endangers the life and health of persons.
CAUTION
Personal injuries!
Failure to follow this safety instruction can lead to injuries to persons.
NOTE
Damage to environment/equipment or data loss
Failure to follow this instruction can lead to environmental damage, equipment damage or data loss.
Tip or pointer
This symbol indicates information that contributes to better understanding.

Foreword
EP3356-0022 7Version: 1.4
1.3 Documentation issue status
Version Comment
1.4 • Front page updated
1.3 • Parallel connection of resistor bridges made clearer
1.2 • Technical Data updated
1.1.0 • Update Safety instructions
• Update chapter Mounting and Cabling
1.0.4 • Technical Data updated
• Signal connection updated
1.0.3 • Basic function principles updated
1.0.2 • Nut torque for connectors updated
1.0.1 • Analog voltage inputs M12 and meaning of the LEDs updated
1.0.0 • First publication
0.5 • First preliminary version
Firm and hardware version
The documentation refers to the firm and hardware status that was valid at the time it was prepared.
The properties of the modules are subject to continuous development and improvement. Modules having
earlier production statuses cannot have the same properties as modules with the latest status. Existing
properties, however, are always retained and are not changed, so that these modules can always be
replaced by new ones.
The firmware and hardware version (delivery state) can be found in the batch number (D number) printed at
the side of the EtherCAT Box.
Syntax of the batch number (D number)
D: WW YY FF HH Example with D No. 29 10 02 01:
WW - week of production (calendar week) 29 - week of production 29
YY - year of production 10 - year of production 2010
FF - firmware version 02 - firmware version 02
HH - hardware version 01 - hardware version 01
Further information on this topic: Version identification of EtherCAT devices [}83].

Product overview
EP3356-00228 Version: 1.4
2 Product overview
2.1 EP3356-0022 - Introduction
Fig.1: EP3356-0022
1-channel precise load cell analysis (resistor bridge), 24 bit
The EP3356 EtherCAT Box enables direct connection of a resistor bridge or load cell in a 4-wire connection
technology. The ratio between the bridge voltage UD and the supply voltage UREF is determined
simultaneously in the input circuit and the final load value is calculated as a process value on the basis of the
settings in the EP3356. With automatic self-calibration (can be deactivated), dynamic filters and distributed
clock support, the EP3356 with measuring cycles of 100 µs can be used for fast and precise monitoring of
torque or vibration sensors.
The EP3356 can also be used to analyze up to four resistor bridges connected in parallel: Further
Information [}16]
Quick links
Installation [}18]
Signal connection [}24]
Basic function principles [}30]
Calibration and adjustment [}42]

Product overview
EP3356-0022 9Version: 1.4
2.2 EP3356-0022 - Technical data
Technical data EP3356-0022
Number of inputs 2, for 1 resistor bridge in full bridge technology
Signal connection sockets [}24] M12
Resolution 24Bit, 32bit presentation
Conversion time 0.1ms…250ms, configurable, max. 10,000 samples/s
Nominal voltage 24VDC (-15%/+20%)
Distributed Clocks yes
selectable modes yes (2)
Measuring error <±0.01% for the calculated load value in relation to the final load value
with a 12V feed and 24mV bridge voltage (hence nominal strain gauge
characteristic value of 2mV/V), self-calibration active, 50Hz filter active.
Attention: Due to external influences such as temperature drifts [}11]
and HF-disturbances may possibly occur a not insignificant error!
Measuring range UDmax. -27mV…+27mV typ. (see note [}51] concerning voltage
measuring recommended: -25mV…+25mV rated voltage
Measuring range Uref max. -13.8V…+13.8V typ. (see note [}51] concerning voltage
measuring recommended: -12V…+12V rated voltage
Supported nominal sensitivity all, resolution of parameter: 0.01µV/V
Recommended: 0.5mV/V…4mV/V
Min. strain gauge resistor parallel operation of strain gauges only with suitable strain gauges
recommended
Input filter limit frequency
(hardware)
10kHz low pass (-3dB)
Filter (software) Present 50Hz,
Configurable: 50/60Hz FIR notch filter, IIR low pass 4-fold averager
Internal resistance >200kΩ (Uref), > 1MΩ (Ud)
Special features self-calibration, quadruple averager, dynamic filters, fast data sampling,
parallel connection
Sensor supply Uref Uref=10V (supplied by the EP3356 from UP)
max. 350mA
Current consumption from US
(without sensor current)
120mA
Power supply connection feed: 1 x M8 male socket, 4-pin
downstream connection: 1 x M8 female socket, 4-pin
Permissible ambient temperature
during operation
-25..+60°C
-25..+55°C (according to cURus, see UL Requirements [}26])
Permissible ambient temperature
during storage
-40°C…+85°C
Vibration / shock resistance conforms to EN60068-2-6 / EN60068-2-27
EMC immunity/emission conforms to EN61000-6-2 / EN61000-6-4
Dimensions 126mm x 60mm x 40mm
Weight approx.. 450g
Installation position variable
Protection class IP65, IP66, IP67 (according to EN60529)
Approvals CE, cURus

Product overview
EP3356-002210 Version: 1.4
2.2.1 Additional checks
The boxes have undergone the following additional tests:
Verification Explanation
Vibration 10 frequency runs in 3 axes
5Hz < f < 60Hz displacement 0.35mm, constant amplitude
60.1Hz < f < 500Hz acceleration 5g, constant amplitude
Shocks 1000 shocks in each direction, in 3 axes
35g, 11ms
2.3 Scope of supply
Make sure that the following components are included in the scope of delivery:
• 1xEtherCAT Box EP3356-0022
• 2x protective cap for EtherCAT socket, M8, green (pre-assembled)
• 1x protective cap for supply voltage input, M8, transparent (pre-assembled)
• 1x protective cap for supply voltage output, M8, black (pre-assembled)
• 10x labels, blank (1 strip of 10)
Pre-assembled protective caps do not ensure IP67 protection
Protective caps are pre-assembled at the factory to protect connectors during transport. They may
not be tight enough to ensure IP67 protection.
Ensure that the protective caps are correctly seated to ensure IP67 protection.

Basic principles of strain gauge technology
EP3356-0022 11Version: 1.4
3 Basic principles of strain gauge technology
Basic information on the technological field of "strain gauges/load cells" as metrological instruments is to be
given below. The information is of general nature; it is up to the user to check the extent to which it applies to
his application.
• Strain gauges serve either to directly measure the static (0 to a few Hz) or dynamic (up to several KHz)
elongations, compressions or torsions of a body by being directly fixed to it, or to measure various
forces or movements as part of a sensor (e.g. load cells/force transducers, displacement sensor,
vibration sensors).
• In the case of the optical strain gauge (e.g. Bragg grating), an application of force causes a
proportional change in the optical characteristics of a fiber used as a sensor. Light with a certain
wavelength is fed into the sensor. Depending upon the deformation of the grating, which is laser-cut
into the sensor, due to the mechanical load, part of the light is reflected and evaluated using a suitable
measuring transducer (interrogator).
The commonest principle in the industrial environment is the electrical strain gauge. There are many
common terms for this type of sensor: load cell, weighbridge, etc.
Structure of electrical strain gauges
A strain gauge consists of a carrier material (e.g. stretchable plastic film) with an applied metal film from
which a lattice of electrically conductive resistive material is worked in very different geometrical forms,
depending on the requirements.
Fig.2: Strain gauge
This utilizes a behavior whereby, for example in the case of strain, the length of a metallic resistance network
increases and its diameter decreases, as a result of which its electrical resistance increases proportionally.
ΔR/R = k*ε
ε = Δl/l thereby corresponds to the elongation; the strain sensitivity is called the k-factor. This also gives rise
to the typical track layout inside the strain gauge: the resistor track or course is laid in a meandering pattern
in order to expose the longest possible length to the strain.
Example
The elongation ε = 0.1% of a strain gauge with k-factor 2 causes an increase in the resistance of 0.2%.
Typical resistive materials are constantan (k~2) or platinum tungsten (92PT, 8W with k ~4). In the case of
semiconductor strain gauges a silicon structure is glued to a carrier material. The conductivity is changed
primarily by deformation of the crystal lattice (piezo-resistive effect); k-factors of up to 200 can be achieved.
Measurement of signals
The change in resistance of an individual strain gauge can be determined in principle by resistance
measurement (current/voltage measurement) using a 2/3/4-conductor measurement technique

Basic principles of strain gauge technology
EP3356-002212 Version: 1.4
Usually 1/2/4 strain gauges are arranged in a Wheatstone bridge (-> quarter/half/full bridge); the nominal
resistance/impedance R0 of all strain gauges (and the auxiliary resistors used if necessary) is usually
equivalent to R1=R2=R3=R4=R0. Typical values in the non-loaded state are R0 = 120Ω, 350Ω, 700Ω and
1kΩ.
The full bridge possesses the best characteristics such as linearity in the feeding of current/voltage, four
times the sensitivity of the quarter-bridge as well as systematic compensation of disturbing influences such
as temperature drift and creeping. In order to achieve high sensitivity, the 4 individual strain gauges are
arranged on the carrier in such a way that 2 are elongated and 2 are compressed in each case.
Fig.3: quarter, half and full bridge
The measuring bridges can be operated with constant current, constant voltage, or also with AC voltage
using the carrier frequency method.
Measuring procedure
The Beckhoff EL/KL335x Terminals and the EP3356 Box support only the constant excitation
•Full bridge strain gauge at constant voltage (ratiometric measurement)
Since the relative resistance change ΔR is low in relation to the nominal resistance R0, a simplified equation
is given for the strain gauge in the Wheatstone bridge arrangement:
UD/UV = ¼ * (ΔR1-ΔR2+ΔR3-ΔR4)/R0
ΔR usually has a positive sign in the case of elongation and a minus sign in the case of compression.
A suitable measuring instrument measures the bridge supply voltage UV (or USupply) and the resulting bridge
voltage UD (or UBridge), and forms the quotients from both voltages, i.e. the ratio. After further calculation and
scaling the measured value is output, e.g. in kg. Due to the division of UD and UV the measurement is in
principle independent of changes in the supply voltage.
If the voltages UV and UD are measured simultaneously, i.e. at the same moment, and placed in relation to
each other, then this is referred to as a ratiometric measurement.
The advantage of this is that (with simultaneous measurement!) brief changes in the supply voltage (e.g.
EMC effects) or a generally inaccurate or unstable supply voltage likewise have no effect on the
measurement.
A change in UV by e.g. 1% creates the same percentage change in UD according to the above equation. Due
to the simultaneous measurement of UD and UV the error cancels itself out completely during the division.
4-conductor vs. 6-conductor connection
If supplied with a constant voltage of 5 to 12V a not insignificant current flows of e.g. 12V/350Ω=34.3mA.
This leads not only to dissipated heat, wherein the specification of the strain gauge employed must not be
exceeded, but possibly also to measuring errors in the case of inadequate wiring due to line losses not being
taken into account or compensated.
In principle a full bridge can be operated with a 4-conductor connection (2 conductors for the supply UV and 2
for the measurement of the bridge voltage UD).
If, for example, a 25m copper cable (feed + return = 50m) with a cross section q of 0.25mm² is used, this
results in a line resistance of
RL = l/ (κ * q) = 50m / (58S*m/mm² * 0.25mm²) = 3.5Ω

Basic principles of strain gauge technology
EP3356-0022 13Version: 1.4
If this value remains constant, then the error resulting from it can be calibrated out. However, assuming a
realistic temperature change of, for example, 30° the line resistance RL changes by
ΔRL =30° * 3.9 * 10-4 * 3.5Ω = 0.41Ω
In relation to a 350Ω measuring bridge this means a measuring error of > 0.1%.
Fig.4: 4-conductor connection
This can be remedied by a 6-conductor connection, in particular for precision applications (only possible with
EL3356).
Fig.5: 6-conductor connection

Basic principles of strain gauge technology
EP3356-002214 Version: 1.4
The supply voltage UV is thereby fed to the strain gauge (= current carrying conductor). The incoming supply
voltage Uref is only measured with high impedance directly at the measuring bridge in exactly the same way
as the bridge voltage UD with two currentless return conductors in each case. The conductor-related errors
are hence omitted.
Since these are very small voltage levels of the order of mV and µV, all conductors should be shielded. The
shield must be connected to pin 5 of the M12 connector.
EP3356-0022: No 6-conductor connection necessary
The connection of a strain gauge over 4-conductor with the EP3356-0022 is sufficient because due
to the shorter cable lengths no measurement errors occur.
Structure of a load cell with a strain gauge
One application of the strain gauge is the construction of load cells.
This involves gluing strain gauges (full bridges as a rule) to an elastic mechanical carrier, e.g. a double-
bending beam spring element, and additionally covered to protect against environmental influences.
The individual strain gauges are aligned for maximum output signals according to the load direction (2 strain
gauges in the elongation direction and 2 in the compression direction).
Fig.6: Example of a load cell
The most important characteristic data of a load cell
Characteristic data
Please enquire tot he sensor manufacturer regarding the exact characteristic data!
Nominal load Emax
Maximum permissible load for normal operation, e.g. 10 kg
Nominal characteristic value mV/V

Basic principles of strain gauge technology
EP3356-0022 15Version: 1.4
The nominal characteristic value 2mV/V means that, with a supply of US=10V and at the full load Emax of the
load cell, the maximum output voltage UD = 10V * 2mV/V *E = 20mV. The nominal characteristic value is
always a nominal value – a manufacturer’s test report is included with good load cells stating the
characteristic value determined for the individual load cell, e.g. 2.0782mV/V.
Minimum calibration value Vmin
This indicates the smallest mass that can be measured without the maximum permissible error of the load
cell being exceeded [RevT].
This value is represented either by the equation Vmin = Emax / n (where n is an integer, e.g. 10000), or in % of
Emax (e.g. 0.01).
This means that a load cell with Emax = 10kg has a maximum resolution of
Vmin = 10kg / 10000 = 1g or Vmin = 10kg * 0.01% = 1g.
Accuracy class according to OIML R60
The accuracy class is indicated by a letter (A, B, C or D) and an additional number, which encodes the scale
interval d with a maximum number nmax (*1000); e.g. C4 means Class C with maximally 4000d scale
intervals.
The classes specify a maximum and minimum limit for scale intervals d:
• A: 50,000 – unlimited
• B: 5000 – 100,000
• C: 500 – 10,000
• D: 500 – 1000
The scale interval nmax = 4000d states that, with a load cell with a resolution of Vmin = 1g, a calibratable set of
scales can be built that has a maximum measuring range of 4000d * Vmin = 4kg. Since Vmin is thereby a
minimum specification, an 8kg set of scales could be built – if the application allows – with the same load
cell, wherein the calibratable resolution would then fall to 8kg/4000d=2g. From another point of view the
scale interval nmax is a maximum specification; hence, the above load cell could be used to build a set of
scales with a measuring range of 4kg, but a resolution of only 2000 divisions = 2g, if this is adequate for the
respective application. Also the classes differ in certain error limits related to non-repeatability/creep/TC
Accuracy class according to PTB
The European accuracy classes are defined in an almost identical way (source: PTB).
Class Calibration values Minimum load Max/e
Minimum
value
Maximum
value
|
Fine scales
0.001g <= e 100 e 50000
||
Precision scales
g <= e <=0.05g
g <= e
20 e
50 e
100
5000
100000
100000
|||
Commercial scales
g <= e <=2g
g <= e
20 e
20 e
100
500
10000
10000
||||
Coarse scales
5g <= e 10 e 100 1000
Minimum application range or minimum measuring range in % of rated load
This is the minimum measuring range/measuring range interval, which a calibratable load cell/set of scales
must cover.
Example: above load cell Emax = 10kg; minimum application range e.g. 40% Emax

Basic principles of strain gauge technology
EP3356-002216 Version: 1.4
The used measuring range of the load cell must be at least 4kg. The minimum application range can lie in
any range between Emin and Emax, e.g. between 2kg and 6kg if a tare mass of 2kg already exists for
structural reasons. A relationship between nmax and Vmin is thereby likewise apparent: 4000 * 1g = 4kg .
There are further important characteristic values, which are for the most part self-explanatory and need not
be discussed further here, such as nominal characteristic value tolerance, input/output resistance,
recommended supply voltage, nominal temperature range etc.
Parallel connection of strain gauges
It is usual to distribute a load mechanically to several strain gauge load cells at the same time. Hence, for
example, the 3-point bearing of a silo container on 3 load cells can be realized. Taking into account wind
loads and loading dynamics, the total loading of the silo including the dead weight of the container can thus
be measured.
The load cells connected mechanically in parallel are usually also connected electrically in parallel.
Since the four M12 sockets of the EP3356 are internally connected to one another, an external parallel
connection is not necessary: if several load cells are connected to the EP3356, they are automatically
connected in parallel. Up to four load cells can be connected.
The three load cells in the above example (silo container) can thus be connected to any three of the M12
sockets of the EP3356.
Note:
• the load cells must be matched to each other and approved by the manufacturer for this mode of
operation
• the impedance of the load cells must be large enough that the maximum output current of the
reference voltage Uref is not exceeded: 350mA.
Fig.7: Example: Parallel connection of three load cells. Up to four load cells can be connected in parallel.
Sources of error/disturbance variables
Inherent electrical noise of the load cell
Electrical conductors exhibit so-called thermal noise (thermal/Johnson noise), which is caused by irregular
temperature-dependent movements of the electrons in the conductor material. The resolution of the bridge
signal is already limited by this physical effect. The rms value en of the noise can be calculated by en =
√4kTRB
In the case of a load cell with R0 = 350Ω at an ambient temperature T = 20°C (= 293K) and a bandwidth of
the measuring transducer of 50Hz (and Boltzmann constant k = 1.38 * 10-23 J/K), the rms en= 16.8nV. The
peak-peak noise epp is thus approx. epp ~ 4* en = 67.3nV.

Basic principles of strain gauge technology
EP3356-0022 17Version: 1.4
Example:
In relation to the maximum output voltage Uout-max of a bridge with 2mV/V and Us = 5V, this corresponds to
Uout-max = 5V * 2mV/V = 10mV. (For the nominal load) this results in a maximum resolution of
10mV/67.3nV = 148588digits. Converted into bit resolution: ln(148588)/ln(2) = 17bits. Interpretation: a
higher digital measuring resolution than 17bits is thus inappropriate for such an analog signal in the first
step. If a higher measuring resolution is used, then additional measures may need to be taken in the
evaluation chain in order to obtain the higher information content from the signal, e.g. hardware low-pass
filter or software algorithms.
This resolution applies alone to the measuring bridge without any further interferences. The resolution of the
measuring signal can be increased by reducing the bandwidth of the measuring unit.
If the strain gauge is glued to a carrier (load cell) and wired up, both external electrical disturbances (e.g.
thermovoltage at connection points) and mechanical vibrations in the vicinity (machines, drives, transformers
(mechanical and audible 50Hz vibration due to magnetostriction etc.)) can additionally impair the result of
measurement.
Creep
Under a constant load, spring materials can further deform in the load direction. This process is reversible,
but it generates a slowly changing measured value during the static measurement. In an ideal case the error
can be compensated by constructive measures (geometry, adhesives).
Hysteresis
If even elongation and compression of the load cell take place, then the output voltage does not follow
exactly the same curve, since the deformation of the strain gauge and the carrier may be different due to the
adhesive and its layer thickness.
Temperature drift (inherent heating, ambient temperature)
Relatively large currents can flow in strain gauge applications, e.g. I=US/R0=10V/350Ω=26mA. The
power dissipation at the sensor is thus PV=U*I=10V*26mA=260mW. Depending on application/carrier
material (= cooling) and ambient temperature, a not insignificant error can arise that is termed apparent
elongation. The sensor manufacturers integrate suitable compensation elements in their strain gauges.
Inadequate circuit technology
As already shown, a full bridge may be able (due to the system) to fully compensate non-linearity, creep and
temperature drift. Wiring-related measuring errors are avoided by the 6-conductor connection.
References
Some organizations are listed below that provide the specifications or documents for the technological field
of weighing technology:
• OIML (ORGANISATION INTERNATIONALE DE MÉTROLOGIE LÉGALE) www.oiml.org/en
• PTB - Physikalisch-Technischen Bundesanstalt www.ptb.de/cms/
•www.eichamt.de
• WELMEC - European cooperation in legal metrology www.welmec.org
• DAkkS – Deutsche Akkreditierungsstelle www.dakks.de
• Fachgemeinschaft Waagen (AWA) im Verband Deutscher Maschinen- und Anlagenbau VDMA
www.vdma.org

Mounting and Cabling
EP3356-002218 Version: 1.4
4 Mounting and Cabling
4.1 Mounting
4.1.1 Dimensions
117
6013.5
26.5
126
Ø 4.5
All dimensions are given in millimeters.
Housing features
Housing material PA6 (polyamide)
Sealing compound polyurethane
Mounting two fastening holes Ø 4.5 mm for M4
Metal parts brass, nickel-plated
Contacts CuZn, gold-plated
Power feed through max. 4A
Installation position variable
Protection class IP65, IP66, IP67 (conforms to EN 60529) when screwed together
Dimensions (H x W x D) approx. 126 x 60 x 26.5 mm (without connectors)

Mounting and Cabling
EP3356-0022 19Version: 1.4
4.1.2 Fixing
NOTE
Dirt during assembly
Dirty connectors can lead to malfunctions. Protection class IP67 can only be guaranteed if all cables and
connectors are connected.
• Protect the plug connectors against dirt during the assembly.
Mount the module with two M4 screws in the centrally located fastening holes.
4.1.3 Tightening torques for plug connectors
Screw connectors tight with a torque wrench. (e.g. ZB8801 from Beckhoff)
Connector diameter Tightening torque
M8 0.4Nm
M12 0.6Nm
4.1.4 Functional earth (FE)
The fastening holes [}19] also serve as connections for the functional earth (FE).
Make sure that the box is earthed with low impedance via both fastening screws. You can achieve this, for
example, by mounting the box on a grounded machine bed.
FE
FE
Fig.8: Functional earth via the fastening holes

Mounting and Cabling
EP3356-002220 Version: 1.4
4.2 EtherCAT
4.2.1 Connectors
NOTE
Risk of confusion: supply voltages and EtherCAT
Defect possible through incorrect insertion.
• Observe the color coding of the connectors:
black: Supply voltages
green: EtherCAT
EtherCAT Box Modules have two green M8 sockets for the incoming and downstream EtherCAT
connections.
Fig.9: EtherCAT connectors
Connection
3 1
24
Fig.10: M8 socket
EtherCAT M8
connector
Core colors
Signal Contact ZB9010, ZB9020, ZB9030, ZB9032,
ZK1090-6292,
ZK1090-3xxx-xxxx
ZB9031 and old versions of
ZB9030, ZB9032, ZK1090-3xxx-
xxxx
TIA-568B
Tx + 1 yellow1) orange/white white/orange
Tx - 4 orange1) orange orange
Rx + 2 white1) blue/white white/green
Rx - 3 blue1) blue green
Shield Housing Shield Shield Shield
1) Core colors according to EN61918
Adaptation of core colors for cables ZB9030, ZB9032 and ZK1090-3xxxx-xxxx
For standardization, the core colors of the ZB9030, ZB9032 and ZK1090-3xxx-xxxx cables have
been changed to the EN61918 core colors: yellow, orange, white, blue. So there are different color
codes in circulation. The electrical properties of the cables have been retained when the core colors
were changed.