Beckhoff KM6551 Operator's manual

Documentation | EN
KM6551
Terminal module for wireless data exchange
2021-03-03 | Version: 2.0.0

Table of contents
KM6551 3Version: 2.0.0
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.......................................................................................................................................8
2.1 Introduction........................................................................................................................................8
2.2 Technical data ...................................................................................................................................9
2.3 Basic Function Principles ................................................................................................................10
2.4 LED displays....................................................................................................................................12
2.5 DIP switch........................................................................................................................................13
3 IEEE802.15.4 ............................................................................................................................................14
3.1 Introduction......................................................................................................................................14
3.2 Interference caused by other radio systems....................................................................................15
4 Mounting and wiring................................................................................................................................17
4.1 Recommended mounting rails.........................................................................................................17
4.2 Mounting and demounting - terminals with traction lever unlocking ................................................17
4.3 Dimensions......................................................................................................................................19
4.4 Connection ......................................................................................................................................19
4.5 Antenna alignment...........................................................................................................................21
4.5.1 Directional characteristic.................................................................................................. 21
4.5.2 Alignment examples ........................................................................................................ 23
4.5.3 Polarization ...................................................................................................................... 23
4.5.4 Placement of the antennas .............................................................................................. 24
4.6 Attenuation and range .....................................................................................................................25
4.6.1 Fresnel zone .................................................................................................................... 25
4.6.2 Attenuation in practice ..................................................................................................... 26
4.6.3 Range of different antenna combinations ........................................................................ 26
4.7 Antennas .........................................................................................................................................27
4.7.1 ZS6100-0900 ................................................................................................................... 28
4.7.2 ZS6100-1800 ................................................................................................................... 30
4.7.3 ZS6200-0400 ................................................................................................................... 32
4.7.4 ZS6201-0410 ................................................................................................................... 34
4.7.5 ZS6201-0500 ................................................................................................................... 36
5 Application examples - overview ...........................................................................................................38
5.1 Peer to peer mode...........................................................................................................................38
5.2 Master-Slave mode .........................................................................................................................38
5.3 Broadcast mode ..............................................................................................................................39
5.4 Energy scan.....................................................................................................................................40
6 TwinCAT ...................................................................................................................................................42
6.1 TwinCAT libraries ............................................................................................................................44
6.2 TwinCAT examples .........................................................................................................................44
6.3 Function blocks................................................................................................................................45
6.3.1 Function block FB_KM6551_MAIN.................................................................................. 45

Table of contents
KM65514 Version: 2.0.0
6.3.2 Energy scan..................................................................................................................... 46
6.3.3 Master/Slave mode.......................................................................................................... 47
6.3.4 Broadcast mode............................................................................................................... 49
7 KS2000 Configuration Software.............................................................................................................52
7.1 KS2000 - Introduction......................................................................................................................52
7.2 Parameterization with KS2000 ........................................................................................................53
7.3 Settings............................................................................................................................................55
7.4 Register ...........................................................................................................................................56
7.5 Process data....................................................................................................................................57
8 Access from the user program ..............................................................................................................59
8.1 Process image.................................................................................................................................59
8.2 Control and Status Bytes.................................................................................................................59
8.2.1 Process data mode.......................................................................................................... 59
8.2.2 Register communication .................................................................................................. 61
8.3 Register overview ............................................................................................................................62
8.4 Register description.........................................................................................................................63
8.5 Examples of Register Communication ............................................................................................65
8.5.1 Example 1: reading the firmware version from Register 9............................................... 65
8.5.2 Example 2: Writing to an user register............................................................................. 66
9 Appendix ..................................................................................................................................................69
9.1 General operating conditions...........................................................................................................69
9.2 EC declaration of conformity ...........................................................................................................71
9.3 Calculating with decibels .................................................................................................................72
9.4 Support and Service ........................................................................................................................72

Foreword
KM6551 5Version: 2.0.0
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®, 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
KM65516 Version: 2.0.0
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
KM6551 7Version: 2.0.0
1.3 Documentation issue status
Version Comment
2.0.0 • Migration
• Structure update
1.2.0 • Included TwinCAT library [}44] updated to version 1.7.0
• Description of the KS2000 configuration software updated
1.1.0 • Register description extended
• Notes on interference caused by other radio systems expanded
• Notes on mounting expanded
• Antenna ZS6201-0500 added
• Antenna descriptions updated
1.0.0 First release
Firmware and hardware versions
Documentation, version Firmware version Hardware version
2.0.0 1F 02
1.2.0 1E 01
1.1.0 1E 00
1.0.0 1B 00
The firmware and hardware versions (delivery state) can be taken from the serial number printed on the side
of the terminal module.
Syntax of the serial number
Structure of the serial number: WWYYFFHH
WW - week of production (calendar week)
YY - year of production
FF - firmware version
HH - hardware version
Example with serial number 35 05 00 01:
35 - week of production 35
05 - year of production 2005
00 - firmware version 00
01 - hardware version 01

Product overview
KM65518 Version: 2.0.0
2 Product overview
2.1 Introduction
Fig.1: KM6551-0000 - Terminal module for radio transmission
The KM6551-0000 terminal module is a data exchange unit based on radio technology. It uses the
IEEE802.15.4 standard. Data is exchanged or transmitted between two independent controllers via radio,
independent of the higher-level fieldbus. The free-field distance between two KM6551-0000 units can be up
to 300m.
The KM6551-0000 terminal module has a reverse SMA plug (Straight Medium Adapter), to which various
radio antennas [}27] can be connected, which are to be procured from Beckhoff. The directional
characteristic can be adapted to the surroundings by means of specifically selecting the antenna. Status and
data exchange are displayed via LEDs, thereby offering fast and simple diagnostics. A TwinCAT library
[}44] is available for the use of the KM6551-0000 terminal module with TwinCAT.

Product overview
KM6551 9Version: 2.0.0
2.2 Technical data
Technical data KM6551-0000
Frequency band 2.4GHz
Data transfer rates 250kbit
Output power 0dBm (1mW)
Reception sensitivity -87dBm
Protocol IEEE802.15.4
Antenna connection reverse SMA plug (RP_SMA)
Power supply for the electronics via the K-bus
Current consumption via K-bus typically 135mA
Width of a bus terminal block Maximum 64 standard Bus Terminals or 80cm
(one KM6551-0000 corresponds to 2 standard Bus Terminals
here)
Data width in the input process image 12bytes
Data width in the output process image 12bytes
Dimensions without antenna (W x H x D) approx. 26.5mm x100mm x 55mm (width aligned: 24mm)
Weight app.100g
Permissible ambient temperature range
during operation
0°C ... + 55°C
Permissible ambient temperature range
during storage
-25°C ... + 85°C
Permissible relative air humidity 95%, no condensation
Mounting [}17] on a 35mm mounting rail [}17] (e.g. DIN rail TH35-7.5
conforming to EN60715)
Vibration/shock resistance conforms to EN60068-2-6/ EN60068-2-27, EN60068-2-29
EMC immunity/emission conforms to EN61000-6-2/ EN61000-6-4
Protection class IP20
Installation position variable
Approval CE

Product overview
KM655110 Version: 2.0.0
2.3 Basic Function Principles
Fig.2: Basic Function Principles
The KM6551-0000 data exchange module enables the wireless exchange of data between two or more
controllers. It uses the IEEE802.15.4 standard as its basis with a Beckhoff-specific protocol. 10bytes of user
data are transmitted per data packet. The DIP switch is used to set the operating mode of the KM6551-0000,
i.e. whether the module functions as a master or slave and which communication mode is to be used.
The data is exchanged in the peer to peer and master-slave modes using the polling method. In broadcast
mode, one module is the broadcast master that sends the data and all other modules are broadcast slaves
that receive the data but cannot send data to the broadcast master themselves. Hence, they listen only to
data from the broadcast master.
In master-slave mode you can decide via the software with which slave data should be exchanged. Up to
7slaves can be addressed.
The data exchange module KM6551-0000 supports 16channels, which are freely selectable and can be
used, for example, to establish several radio networks or for placement outside WLANs or other radio
systems that also use 2.4GHz.
The KM6551-0000 can scan the possible 16 channels. The energy in the frequency range is measured to
ascertain in advance whether other systems are active and on which frequencies. Furthermore, the so-called
LQI (LinkofQualityIndex) is transmitted with each data telegram. This makes it possible to determine the
quality of the signal. A high LQI value indicates a good connection, a low value a poor connection. In order to
improve the LQI value, a larger antenna or an antenna with a correspondingly larger transmission factor can
be used.
Communication mode
The KM6551-0000 data exchange module supports three different communication modes.
Mode 1: Peer to peer – data exchange between two modules
Enables the exchange of data between two KM6551-0000. A maximum of 10bytes of data can be
transmitted per cycle. In one cycle (typically < 20ms), module1 sends data to module2 and module2 sends
data back to module1.

Product overview
KM6551 11Version: 2.0.0
Fig.3: Peer to Peer
Mode 2: Master-slave – data exchange between a master and up to 7slaves
In master-slave mode the master can communicate with up to seven KM6551-0000 using the polling
method. To do this, set the corresponding slave addresses using the DIP switch. From the PLC you can
inform the master which slave it should communicate with, how often and for how long. Approx. 20ms are
required per slave. For seven slaves this results in a minimum cycle time of 140ms which the master
requires in order to address all 7 slaves once each.
Fig.4: Master-Slave mode
Mode 3: Broadcast to any number of slaves
In broadcast mode, only the broadcast master transmits. All other modules (broadcast slaves) can only
receive data but cannot send data themselves. Any number (x) of broadcast slaves can listen in.

Product overview
KM655112 Version: 2.0.0
Fig.5: Broadcast mode
Support of the KM6551-0000 using Bus Couplers, Bus Terminal Controllers and
TwinCAT
The KM6551-0000 is supported from TwinCAT 2.10 Build 1326 onwards. The following Bus Cou-
plers are supported: BK1120, BK1250, BK2020, BK3120, BK3150, BK9000, BK9050. (Further Bus
Couplers on request). All Bus Terminal Controllers from the BCxxxx, BXxxxx and BXxxxx series are
supported.
NOTE
CE conformity
The CE conformity of the KM6551-0000 is only guaranteed if it is operated with original Beckhoff acces-
sories (antennas [}27], coaxial cable [}19])!
2.4 LED displays
KM6551-0000
Fig.6: KM6551 - LED displays

Product overview
KM6551 13Version: 2.0.0
LED Display
Run (green) off Data transmission on the K-bus is not active
on Data transmission on the K-bus is active
Rx (green) on Data being received via radio
Tx (green) on Data being sent via radio
Link (green, orange, red) on Green - good signal quality
Orange - moderate signal quality
Red - poor signal quality or watchdog has triggered
2.5 DIP switch
You can activate the different modes of the KM6551-0000 using the DIP switch. This enables the simple
exchange of the modules without additional configuration software.
• DIP switch in right position: ON
• DIP switch in left position: OFF
The picture illustrates the setting for Slave 5.
Fig.7: DIP switch
DIP switch A B C D
Master mode OFF OFF OFF OFF
Slave 1 ON OFF OFF OFF
Slave 2 OFF ON OFF OFF
Slave 3 ON ON OFF OFF
Slave 4 OFF OFF ON OFF
Slave 5 ON OFF ON OFF
Slave 6 OFF ON ON OFF
Slave 7 ON ON ON OFF
Broadcast slave OFF OFF OFF ON

IEEE802.15.4
KM655114 Version: 2.0.0
3 IEEE802.15.4
3.1 Introduction
The terms IEEE802.15.4 and ZigBee are used in many places as synonyms, although there is a clear
demarcation between them, which will be briefly explained at this point.
The 802.15.4 standard, which was elaborated by the Institute of Electrical and Electronics Engineers (IEEE),
specifies the Physical Layer (PHY) and the Medium Access Control (MAC), which correspond to the two
lowest levels of the OSI layer model. The IEEE802.15.4 standard was ratified at the beginning of May 2004
[1]. Therefore, apart from a few expected amendments and clarifications, work on it is deemed to be
complete.
The ZigBee Alliance [2] was founded by several large firms from the semiconductor industry with the aim of
developing a complete protocol suite on the basis of IEEE802.15.4 for wireless communication extending up
to the application interface. However, it is worth mentioning in this respect that the IEEE802.15.4 standard is
in no way linked to the ZigBee Alliance.
No ZigBee!
The KM6551-0000 data transmission module is based on IEEE802.15.4, but it is not a ZigBee
product and is also not ZigBee-compatible!
Technical data KM6551
Data transmission band 2.4GHz
Channels 16
Channel separation 5MHz
Channel width 2MHz
Available Worldwide
Data transfer rate 250kbit
Protocol IEEE802.15.4
16 channels, each with a gross data rate of 250kB/s, are available in the worldwide available 2.4GHz band.
Fig.8: Channels 11 to 26
[1] Institute of Electrical and Electronics Engineers (Ed.): IEEE Standard for Information technology --
Telecommunication and information exchange between systems -- Local and metropolitan area networks --
Specific requirements. Part 15.4: Wireless Medium Access Control (MAC) and Physical Layer (PHY)
Specifications for Low-Rate Wireless Personal Area Networks (LR-WPANs).IEEE Computer Society, New
York, NY, USA, October 2003
[2] ZigBee Alliance, http://www.zigbee.org

IEEE802.15.4
KM6551 15Version: 2.0.0
3.2 Interference caused by other radio systems
Check frequency ranges
• WLAN networks on adjacent or the same channels
• Microwave ovens
WLAN
If the IEEE802.15.4 channel used by the KM6551-0000 and the frequency range of a neighboring WLAN
network overlap, this can lead to disruptions in the KM6551-0000 communication.
Select an IEEE802.15.4 channel for the KM6551-0000 that uses the gaps between neighboring WLAN
networks as shown in the figure below.
Even if the maximum possible three non-overlapping WLAN channels are used adjacently, four
IEEE802.15.4 channels remain that the KM6551-0000 can use without interference.
Fig.9: Utilizing gaps between adjacent WLAN networks
1. Three non-overlapping WLAN networks in the WLAN channels permitted in North America (IEEE
802.11b)
2. Three non-overlapping WLAN networks in the WLAN channels permitted in Europe (IEEE 802.11b)
3. Placement of EEE802.15.4 channels (2400MHz PHY) in the gaps between WLAN networks

IEEE802.15.4
KM655116 Version: 2.0.0
Microwave ovens
Since microwave ovens typically operate at a frequency of 2.455GHz, neighboring poorly screened ovens
can interfere with the transmission between the KM6551-0000.
In this case, remove the interfering devices or use only well-screened microwave ovens in the direct vicinity
of the KM6551-0000.

Mounting and wiring
KM6551 17Version: 2.0.0
4 Mounting and wiring
4.1 Recommended mounting rails
Terminal Modules und EtherCAT Modules of KMxxxx and EMxxxx series, same as the terminals of the
EL66xx and EL67xx series can be snapped onto the following recommended mounting rails:
• DIN Rail TH35-7.5 with 1mm material thickness (according to EN60715)
• DIN Rail TH35-15 with 1,5mm material thickness
Pay attention to the material thickness of the DIN Rail
Terminal Modules und EtherCAT Modules of KMxxxx and EMxxxx series, same as the terminals of
the EL66xx and EL67xx seriesdoes not fit to the DIN Rail TH35-15 with 2,2 to 2,5mm material
thickness (according to EN60715)!
4.2 Mounting and demounting - terminals with traction
lever unlocking
The terminal modules are fastened to the assembly surface with the aid of a 35 mm mounting rail (e.g.
mounting rail TH 35-15).
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 recommended mounting rails under the terminals and cou-
plers, you should use flat mounting connections (e.g. countersunk screws or blind rivets).
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!
Mounting
• Fit the mounting rail to the planned assembly location.

Mounting and wiring
KM655118 Version: 2.0.0
and press (1) the terminal module against the mounting rail until it latches in place on the mounting
rail (2).
• Attach the cables.
Demounting
• Remove all the cables. Thanks to the KM/EM connector, it is not necessary to remove all the cables
separately for this, but for each KM/EM connector simply undo 2 screws so that you can pull them off
(fixed wiring)!
• Lever the unlatching hook on the left-hand side of the terminal module upwards with a screwdriver (3).
As you do this
◦ an internal mechanism pulls the two latching lugs (3a) from the top hat rail back into the terminal
module,
◦ the unlatching hook moves forwards (3b) and engages

Mounting and wiring
KM6551 19Version: 2.0.0
• In the case 32 and 64 channel terminal modules (KMxxx4 and KMxxx8 or EMxxx4 and EMxxx8) you
now lever the second unlatching hook on the right-hand side of the terminal module upwards in the
same way.
• Pull (4) the terminal module away from the mounting surface.
4.3 Dimensions
Fig.10: KM6551 dimensions
4.4 Connection
The antennas are connected via a reverse SMA screw plug. Please screw the cable, the coaxial cable or the
antenna hand tight to this screw plug.

Mounting and wiring
KM655120 Version: 2.0.0
Coaxial cable
Name Description
ZK6000-0102-0020 Coaxial cable, characteristic impedance 50Ω, preassembled plug connectors (SMA
plug and reverse SMA socket), black, 2m
ZK6000-0102-0040 Coaxial cable, characteristic impedance 50Ω, preassembled plug connectors (SMA
plug and reverse SMA socket), black, 4m