Beckhoff KS3403 User manual

Documentation | EN
KL3403/KS3403
3-Phase Power Measurement Terminals
2022-09-30 | Version: 3.2.0

Table of contents
KL3403/KS3403 3Version: 3.2.0
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 ......................................................................................................................................9
2.1 Introduction .......................................................................................................................................9
2.2 LED display .....................................................................................................................................10
2.3 Technical data.................................................................................................................................11
2.4 Basic function principles..................................................................................................................12
2.5 Current transformer.........................................................................................................................17
2.5.1 Current transformers from Beckhoff................................................................................. 18
3 Mounting and wiring ...............................................................................................................................19
3.1 Instructions for ESD protection .......................................................................................................19
3.2 Installation on mounting rails...........................................................................................................20
3.3 Disposal ..........................................................................................................................................22
3.4 Connection ......................................................................................................................................23
3.4.1 Connection system........................................................................................................... 23
3.4.2 Wiring ...............................................................................................................................24
3.4.3 Connection .......................................................................................................................26
3.5 Application examples ......................................................................................................................27
3.5.1 Application examples for alternating current .................................................................... 28
3.5.2 Application example for DC.............................................................................................. 30
3.5.3 Application example with frequency converter................................................................. 31
3.5.4 Application example for KL3403-0014 ............................................................................. 33
4 KS2000 Configuration Software ...........................................................................................................35
4.1 KS2000 - Introduction .....................................................................................................................35
4.2 Parameterization with KS2000........................................................................................................36
4.3 Settings ...........................................................................................................................................38
5 Programming...........................................................................................................................................41
5.1 Datenstrukturen...............................................................................................................................41
5.1.1 Process image ................................................................................................................. 41
5.1.2 Control and status bytes .................................................................................................. 42
5.1.3 Register overview............................................................................................................. 45
5.1.4 Register description ......................................................................................................... 45
5.2 Examples of Register Communication ............................................................................................49
5.2.1 Example 1: Reading the firmware version from register 9 ............................................... 49
5.2.2 Example 2: Writing to an user register ............................................................................. 50
5.3 Reading the process data ...............................................................................................................52
5.4 Sample program for register communication via EtherCAT on KL3314 exemplary........................54
6 Appendix..................................................................................................................................................57
6.1 Error correction ...............................................................................................................................57
6.2 Measuring error due to input overload ............................................................................................58
6.3 Measuring error for DC voltage measurement................................................................................61

Table of contents
KL3403/KS34034 Version: 3.2.0
6.4 Beckhoff Identification Code (BIC) ..................................................................................................62
6.5 Support and Service........................................................................................................................64

Foreword
KL3403/KS3403 5Version: 3.2.0
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®, TwinCAT/BSD®, TC/BSD®, 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
KL3403/KS34036 Version: 3.2.0
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
KL3403/KS3403 7Version: 3.2.0
1.3 Documentation issue status
Version Comment
3.2.0 • Chapter Technical data updated
• Chapter Current transformers from Beckhoff added
• Chapter Disposal added
• Chapter Beckhoff Identification Code (BIC) updated
• Document structure updated
• New title page
3.1.0 • KL3403-0333 added
• KL3403-0021 deleted
• Technical data updated
• Chapter Instructions for ESD protection added
• Example program added to chapter “KS2000 Configuration software“
• Design of the safety instructions adapted to IEC82079-1
3.0.0 • Migration
2.1.0 • Register description updated
• Chapter KS2000 settings updated
• Chapter Control and status byte updated
• Technical data updated
2.0.1 • Firmware versions updated
• Numerical values for KL3403-0022 corrected
2.0.0 • Permitted ambient temperature range for KL3403-0000 and KL3403-0010 extended
• Technical data updated
• Chapter Basic function principles expanded
1.9.0 • UL notes updated
• Technical data updated
1.8.0 • UL notes added
• Technical data updated
1.7.0 • Application example with frequency converter updated
• Technical data updated
1.6.0 • Description of KL3403-0014 added
• Mounting description expanded
1.5.0 • Description of KL3403-0021, KL3403-0022, KL3403-0025 and KL3403-0026 added
• Description of the flexible process image added
• Energy meter can be inverted (for generator mode)
• Min. values of current, voltage and power
• Automatic deletion of the minimum and maximum values
1.4.1 • Feature register extended
1.4 • KL3403-0020 (20mA) added
• Chapter Measuring error due to input overload added
• Chapter Measuring error with DC voltage measurement added
1.3 • Information on current, power and energy measurement resolution for KL3403-0010 terminal version corrected.
1.2 • Description of control and status bytes extended: Process data index for frequency measurement amended
• Description of the KL3403 parameterization with the KS2000 software updated
• Channel numbering in the descriptions adapted to the display in TwinCAT and KS2000
• Default value for measuring cycle time corrected to 50ms
• Application example with frequency converter added
1.1 • Technical data updated
• Description of KL3403-0010 (5A version) added
• DC application example added

Foreword
KL3403/KS34038 Version: 3.2.0
Version Comment
1.0 • Description of KL3403 parameterization via KS2000 software added
• Register description amended
- Commands amended
- Feature register description added
- Description of the undervoltage threshold register added
• Examples for register communication added
• Description of control and status bytes extended:
- Further process data indices amended
• Technical data updated
0.4 • Technical data added
• Application examples revised
• Description of control and status bytes extended:
• English version available
0.3 • Notes on measuring interval revised
0.2 • Further application example added
• Description of the connections added
• Register description amended
0.1 • First preliminary version
Firmware (FF) and hardware versions (HH)
Documen-
tation,
Version
KL3403-0000 KL3403-0010 KL3403-0014 KL3403-0020 KL3403-0022 KL3403-0025,
KL3403-0026
KL3403-0333
FF HH FF HH FF HH FF HH FF HH FF HH FF HH
3.2.0 3L 18 3L 18 4K 18 4K 17 4K 18 3L 18 4K 17
3.1.0 3L 17 3L 17 4K 17 4K 17 4K 17 3L 17 4K 17
3.0.0 3L 17 3L 17 4K 17 4K 17 4K 17 3L 17 - -
2.1.0 3L 15 3L 15 4K 16 4K 15 4K 16 3L 15
2.0.1 3L 15 3L 15 4K 15 4K 15 4K 15 3L 15
2.0.0 3K 15 3K 15 4J 15 4J 15 4J 15 3K 15
1.9.0 3K 15 3K 15 4J 15 4J 15 4J 15 3K 15
1.8.0 3K 15 3K 15 4J 15 4J 15 4J 15 3K 15
1.7.0 3J 15 3J 14 4i 15 4i 15 4i 15 3J 15
1.6.0 3H 10 3H 10 3H 10 4G 10 3H 10 3H 10
1.5.0 3G 10 3G 10 - - 4F 10 4F 10 3G 10
1.4.1 3F 10 3F 10 4E 10 - - - -
1.4 3E 10 3E 10 4D 10
1.3 3E 10 3E 04 - -
1.2 3D 09 3D 03
1.1 3B 06 3B 00
1.0 2E 03 - -
The firmware and hardware versions (delivery state) can be taken from the serial number printed on the side
of the terminal.
The current firmware version is also displayed by the KS2000 [}38] configuration software.
Syntax of the serial number
Structure of the serial number: WWYYFFHH
WW - week of production (calendar week)
YY - year
FF - firmware version
HH - hardware version
Example with serial number 35 04 2E 03:
35 - week of production 35
04 - year of production 2004
2E - firmware version 2E
03 - hardware version 03

Product overview
KL3403/KS3403 9Version: 3.2.0
2 Product overview
2.1 Introduction
Fig.1: KL3403
The 3-phase Power Measurement Terminal KL3403 enables the measurement of the electrical data of a
three-phase supply network:
• The voltage is measured via the connection of the network at the terminal points L1, L2, L3 and N.
• The current of the three phases is fed in via current transformers [}17] at the terminal points IL1, IL2, IL3
and IN.
Non-sinusoidal voltage and current curves can also be read in with a practical accuracy of 1% to 5%,
depending on the shape of the curve. The limit frequency of the calculations amount to 2kHz. As the time
interval for calculating the values can be adjusted, optimization is possible under a very wide range of
circumstances.
Pre-processing of the KL3403 provides rms values in the process image, without requiring high computing
power on the controller. From the effective values for voltage (U) and current (I), the KL3403 calculates the
active power (P), the energy consumption (W) and the power factor (cosφ) for each phase. From these
values the apparent power (S) and the phase shift angle (j), forexample, can easily be derived.
The KL3403 thus enables a comprehensive network analysis to be carried out via the fieldbus. Based on the
values for voltage, current, active power, apparent power and loading condition, the plant operator can
optimize the supply of a drive or a machine and protect the plant from damage and downtime.

Product overview
KL3403/KS340310 Version: 3.2.0
Versions
Several variants of the KL3403 are available.
Name Comment Nominal value
KL3403-0000
KS3403-0000
Standard version 1A
KL3403-0026 Like KL3403-0000, but without EMC leakage capacitor between
terminal points 4/8 [}26] and the grounding contact for the
mounting rail.
1A
KL3403-0010
KS3403-0010
Power measurement terminal with higher-capacity current circuits. 5A
KL3403-0014 Power measurement terminal with 3 additional voltage circuits
instead of the current circuits. For connecting external shunts.
60mV
KL3403-0020 Power measurement terminal with more sensitive current circuits. 20mA
KL3403-0022 Power measurement terminal with 6 current circuits, otherwise like
KL3403-0020.
20mA
KL3403-0025 Power measurement terminal with more sensitive current circuits. 250mA
KL3403-0333 Power measurement terminal designed for usage with 333mV
transformers.
max. 333mV(AC),
via current transformer
xA/333 mV
Further details can be found in chapter Technical data [}11].
2.2 LED display
Fig.2: LEDs
LED No. Display
K-Bus run (green) A K-Bus data transfer
ERR L1 (red) B Voltage between L1 and N less than 10V (default*) *) For each channel the
undervoltage threshold value
can be modified with its
register R36 [}48].
ERR L2 (red) C Voltage between L2 and N less than 10V (default*)
ERR L3 (red) D Voltage between L3 and N less than 10V (default*)
For pin assignment see Connecting the KL3403 [}26].

Product overview
KL3403/KS3403 11Version: 3.2.0
2.3 Technical data
Technical data KL3403-... / KS3403-...
0000 0010 0014 0020 0022 0025 0026 0333
Measured values U, I U, I U1) U, I I2) U, I U, I U, I
Calculated parameters Active power, energy, power factor (cosj)
Measuring voltage max. 500VAC 3~ - max. 500VAC 3~
Measuring voltage according to
UL specifications (see UL compli-
ance)
max. 300VAC 3~ - max. 300VAC 3~
Measur-
ing cur-
rent
(continu-
ous oper-
ation)
direct (max.) 1A 5A 60mV1) 20mA 20mA 250mA 1A 333mV (AC)
via current transform-
ers with transforma-
tion
ratio R (max.)
R x 1A R x 5A - R x 20mA R x 20mA R x 250mA R x 1A R x 333mV
Voltage circuit input resistance
(typical)
500kΩ 500kΩ 500kΩ 500kΩ 10Ω2) 500kΩ 500kΩ 500kΩ
Current circuit input resistance
(typical)
33mΩ 6.8mΩ app. 10kΩ1) 10Ω 10Ω 100mΩ 33mΩ 40kΩ
Resolution 16bit (internal 21bit)
Frequency range 10Hz to 500Hz
0Hz to 500Hz (with deactivated DC filter [}38] and with current transformers [}17], which sup-
port this frequency range)
Limit frequency app. 2kHz
Signal type any (taking into account the frequency range and the limit frequency)
Measuring accuracy
for sinusoidal cur-
rent/voltage (total
measuring range,
based on the full
scale value)
Voltage 0.5% 0.5% 0.5% 0.5% - 0.5%
Current 0.5%
3.0%3)
1.0%
3.0%3)
- 0.5% 0.5% 0.5%
Power
(calcu-
lated)
1.0%
4.0%3)
1.5%
4.0%3)
- 1.0% - 1.0%
Measuring procedure True RMS with 64000samples/s
Measuring cycle time freely configurable (50ms per measured value pre-set)
Dielectric strength 1500V (terminal/K-Bus)
Bit width in the input process im-
age
72bits inputs (3x8bits status, 3x16bits data)
Bit width in the output process
image
72bits outputs (3x8bits control, 3x16bits data)
Power supply for the electronics via the K-bus
Current consumption from K-bus typically 115mA
Pluggable wiring at all KSxxxx series terminals
Permissible ambient temperature
range during operation
-25°C ... + 60°C 0°C ... + 55°C
Permissible ambient temperature
range during storage
-40°C ... + 85°C -25°C ... + 85°C
Permissible relative air humidity 95%, no condensation
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
Weight app. 75g
Dimensions (W x H x D) app. 15mmx100mmx70mm (width aligned: 12mm)
Mounting [}20] on 35mm mounting rail conforms to EN60715
Installation position variable
Protection class IP20
Approvals/markings* CE, UKCA, UL, EAC CE, UKCA,
EAC
CE, UKCA, UL, EAC CE, UKCA, EAC
*) Real applicable approvals/markings see type plate on the side (product marking).
1) for KL3403-0014: three additional voltage circuits instead of the current circuits: 60mV for connection of external shunts
2) for KL3403-22: three additional current circuits instead of the voltage circuits: also 20mA
3) the measuring accuracy is reduced, if the extended temperature range is used (-25°C ... + 60°C)

Product overview
KL3403/KS340312 Version: 3.2.0
2.4 Basic function principles
Measuring principle
The KL3403 works with 6analog/digital converters for recording the current and voltage values of all
3phases. The values are sampled with a time grid of approximately 16µs.
Recording and processing is synchronous and identical for the 3phases. The signal processing for one
phase is described below. This description applies correspondingly for all 3phases. The total power and the
total energy consumption represent the sum of the 3phases, the mean current represents the average.
Voltage u and current i curves
Fig.3: Voltage u and current i curves
RMS value calculation
The rms value for voltage and current is calculated over a measuring interval, in this case the period T. The
following equations are used:
u(t): instantaneous voltage value
i(t): instantaneous current value
n: number of measured values
For a measurement in a 50Hz mains system (period T = 20ms), 1280measured values are considered
within a calculation.
Measuring interval
The choice of the right measuring interval is important for the quality of the measurement. The measuring
interval must be at least ¼T. ¼T, ½T, T end multiples of ½T are sensible values. If a random interval is
used that does not correspond to a multiple of ½T and is significantly less than 5T, the measured value will
fluctuate significantly.
The default setting for the measuring interval is 50ms, corresponding to 2.5T in a 50 Hz mains system and
3T in a 60Hz mains system. Experience shows that this is a good compromise between measuring speed
and stability. Deviations from this value are only advisable in the event of particular measurement
requirements (e.g.high measuring speed, low signal frequencies or special current curves).

Product overview
KL3403/KS3403 13Version: 3.2.0
Power measurement
Active power measurement
The KL3403 measures the active power P according to the following equation
P: Active power
n: number of samples (64000 samples / s)
u(t): Instantaneous voltage value
i(t): instantaneous current value
Power s(t) curve
Fig.4: Power s(t) curve
In the first step, the power s(t) is calculated at each sampling instant:
The mean value over the measuring interval is calculated. Here too, the correct choice of the intervals is
important, as described in section RMS value measurement (the interval can only be changed
simultaneously for U, I and P).
The power frequency is twice that of the corresponding voltages and currents.
Apparent power measurement
In real networks, not all consumers are purely ohmic. Phase shifts occur between current and voltage. This
does not affect the methodology for determining the rms values of voltage and current as described above.
The situation for the active power is different: Here, the product of effective voltage and effective current is
the apparent power.

Product overview
KL3403/KS340314 Version: 3.2.0
The active power is smaller than the apparent power.
S: Apparent power
P: Active power
Q: Reactive power
φ: Phase shift angle
u(t), i(t), p(t) curves with phase shift angle φ
Fig.5: u(t), i(t), p(t) curves with phase shift angle φ

Product overview
KL3403/KS3403 15Version: 3.2.0
In this context, further parameters of the mains system and its consumers are significant:
• apparent power S
• reactive power Q
• power factor cos φ
The KL3403 determines the following values:
• active power P
• effective voltage U
• effective current I
From these values, the required parameters can be calculated:
• apparent power:
• reactive power:
• Power factor:

Product overview
KL3403/KS340316 Version: 3.2.0
Sign for power measurement
The sign of the active power P and of the power factor cosφ provide about information the direction of the
energy flow. A positive sign indicates the motor mode, a negative sign indicates generator mode.
In addition, the sign of the reactive power Q indicates the direction of the phase shift between current and
voltage. The diagram Four-quadrant representation of active/reactive power in motor and generator mode
illustrates this. In motor mode (quadrant I & IV) a positive reactive power indicates an inductive load, a
negative reactive power indicates a capacitive load. In generator mode (quadrant II & III), an inductive acting
generator is indicated by a positive reactive power, a capacitive acting generator by a negative reactive
power.
Fig.6: Four-quadrant representation of active/reactive power in motor and generator mode
Peak current measurement
A distinction has to be made between the peak instantaneous value and the peak rms value. The peak rms
value always refers to the peak value within the specified measuring interval.
Frequency measurement
The KL3403 can measure the frequency of the input signals at the voltage circuits (L1, L2, L3). The
measurement takes 5seconds (measuring interval).
Measuring error
Frequency < 70Hz ≥ 70Hz ≥ 75Hz ≥ 80Hz ≥ 90Hz ≥ 100Hz
Measuring error < 0.0% < 0.2% < 0.5% < 1.5% < 2.0% < 3.0%

Product overview
KL3403/KS3403 17Version: 3.2.0
2.5 Current transformer
In principle, the choice of current transformer for the KL3403 is not critical. The internal resistance within the
current circuit of the KL3403 is so small that it is negligible for the calculation of the total resistances of the
current loop. The transformers should be able to produce a secondary rated current of 1A. The primary
rated current Ipn can be selected arbitrarily. The common permissible overload of 1.2xIpn is no problem for
the KL3403, but may lead to small measuring inaccuracies.
Accuracy
Please note that the overall accuracy of the set-up consisting of KL3403 and current transformers to a large
degree depends on the accuracy class of the transformers.
Approval and certification
A set-up with a class 0.5 current transformer cannot be approved or authenticated. The KL3403 is
not an approved billing meter according to the electricity meter standard (DIN43856).
Current types
The KL3403 can measure any current type up to a limiting proportion of 2kHz. Since such currents are
frequently created by inverters and may contain frequencies of less than 50Hz or even a DC component,
electronic transformers should be used for such applications. The KL3403 is also available as a special
version with an interface for ±20mA.
Overcurrent limiting factor FS
The overcurrent limiting factor FS of a current transformer indicates at what multiple of its primary rated
current the current transformer changes to saturation mode, in order to protect the connected measuring
instruments.
NOTE
Please note the rated current!
The KL3403 must not be subjected to more than 5A for a prolonged period of time! For systems in which
the over-current limiting factors of the transformers allow secondary currents of more than 5A, additional
intermediate transformers with a ratio of 5A/1A or 1A/5A should be used!
Protection against dangerous touch voltages
During appropriate operation of the KL3403 with associated current transformers, no dangerous voltages
occur. The secondary voltage is in the range of a few Volts. However, the following faults may lead to
excessive voltages:
• Open current circuit of one or several transformers
• Neutral conductor cut on the voltage measurement side of the KL3403
• General insulation fault
WARNING
Ensure accidental-contact protection!
The complete wiring of the KL3403 must be protected against accidental contact and equipped with associ-
ated warnings! The insulation should be designed for the maximum conductor voltage of the system to be
measured!
The KL3403 allows a maximum voltage of 500V for normal operating conditions. The conductor voltage on
the current side must not exceed 500 V! For higher voltages, an intermediate transformer stage should be
used!

Product overview
KL3403/KS340318 Version: 3.2.0
On the voltage measurement side, a KL3403 is equipped with a protection impedance of 500kΩ. If the
neutral conductor is not connected and only one connection on the side of the voltage measurement is live,
the resulting voltage against earth in a 3-phase system with a phase-to-phase voltage of 400VAC is 230VAC.
This should also be measured on the side of the current measurement using a multimeter with an internal
resistance of 10MΩ, which does not represent an insulation fault.
Additional measuring instruments in the current circuit
Please note that the addition of additional measuring instruments (e.g.ammeters) in the current circuit can
lead to a significant increase in the total apparent power.
Furthermore, connection IN of the KL3403 must represent a star point for the three secondary windings.
Additional measuring instruments therefore have to be potential-free and must be wired accordingly.
2.5.1 Current transformers from Beckhoff
With the seamless completion of the power measurement chain from the sensor to the cloud Beckhoff
enables a much simpler energy management system and at the same time optimizes the availability of
machines and systems. Constant power measurement across the board allows comprehensive inline
analyses to be carried out, which record any deviation and enable quick intervention.
Fig.7: SCT current transformers - Starting point of the Beckhoff measurement chain
All current transformers available from Beckhoff can be found on the internet at
https://www.beckhoff.com/sct
The SCT current transformers allow reliable power sensor technology to be implemented directly in the field
as an integral part of the PC-based control system. Users can choose between two concepts, which are
highly scalable thanks to various designs and performance classes and are thus suitable for any application.
The SCT series portfolio is extremely diversified, ranging from the low-cost 3-phase transformer sets for
properties and standard industrial transformers for mechanical engineering, through to solutions for test
benches with particularly high requirements for accuracy.
The choice of the right product category depends on the type of usage: Whilst the data acquisition can be
implemented cost-efficiently and with high measurement accuracy using the ring-type current transformers,
particularly in new systems, the split-core current transformers are suitable as an uncomplicated retrofit
solution due to the simplicity of their attachment.
• as ring-type or split-core current transformers
• for new systems and for retrofits
• various designs and performance classes
• wide application range from properties to test benches

Mounting and wiring
KL3403/KS3403 19Version: 3.2.0
3 Mounting and wiring
3.1 Instructions for ESD protection
NOTE
Destruction of the devices by electrostatic discharge possible!
The devices contain components at risk from electrostatic discharge caused by improper handling.
• Please ensure you are electrostatically discharged and avoid touching the contacts of the device directly.
• Avoid contact with highly insulating materials (synthetic fibers, plastic film etc.).
• Surroundings (working place, packaging and personnel) should by grounded probably, when handling
with the devices.
• Each assembly must be terminated at the right hand end with a KL9010 bus end terminal, to ensure the
protection class and ESD protection.
Fig.8: Spring contacts of the Beckhoff I/O components

Mounting and wiring
KL3403/KS340320 Version: 3.2.0
3.2 Installation on mounting rails
WARNING
Risk of electric shock and damage of device!
Bring the bus terminal system into a safe, powered down state before starting installation, disassembly or
wiring of the bus terminals!
Assembly
Fig.9: Attaching on mounting rail
The bus coupler and bus terminals are attached to commercially available 35mm mounting rails (DIN rails
according to EN60715) by applying slight pressure:
1. First attach the fieldbus coupler to the mounting rail.
2. The bus terminals are now attached on the right-hand side of the fieldbus coupler. Join the compo-
nents with tongue and groove and push the terminals against the mounting rail, until the lock clicks
onto the mounting rail.
If the terminals are clipped onto the mounting rail first and then pushed together without tongue and
groove, the connection will not be operational! When correctly assembled, no significant gap should
be visible between the housings.
Fixing of mounting rails
The locking mechanism of the terminals and couplers extends to the profile of the mounting rail. At
the installation, the locking mechanism of the components must not come into conflict with the fixing
bolts of the mounting rail. To mount the mounting rails with a height of 7.5mm under the terminals
and couplers, you should use flat mounting connections (e.g. countersunk screws or blind rivets).