Beckhoff CU1521 Series User manual

Documentation | EN
CU1521-xxxx, CU1561
EtherCAT Media Converter (RJ45, LWL, POF)
2023-05-25 | Version: 2.5

Table of contents
CU1521-xxxx, CU1561 3Version: 2.5
Table of contents
1 Foreword....................................................................................................................................................5
1.1 CU15x1 - Product overview ..............................................................................................................5
1.2 Notes on the documentation .............................................................................................................6
1.3 Guide through documentation...........................................................................................................7
1.4 Safety instructions.............................................................................................................................8
1.5 Documentation issue status ..............................................................................................................9
1.6 Version identification of EtherCAT devices .....................................................................................10
1.6.1 General notes on marking................................................................................................10
1.6.2 Version identification of CU Switches .............................................................................. 11
1.6.3 Beckhoff Identification Code (BIC) ................................................................................... 12
1.6.4 Electronic access to the BIC (eBIC).................................................................................14
2 Product overview ....................................................................................................................................16
2.1 Introduction .....................................................................................................................................16
2.2 Technical data.................................................................................................................................18
3 Basic principles.......................................................................................................................................19
3.1 EtherCAT basics .............................................................................................................................19
3.2 EtherCAT cabling – wire-bound ......................................................................................................19
3.3 EtherCAT State Machine ................................................................................................................20
3.4 CoE - Interface: notes .....................................................................................................................21
4 Mounting and wiring ...............................................................................................................................22
4.1 Dimensions .....................................................................................................................................22
4.2 Mounting and demounting...............................................................................................................23
4.3 Diagnostic LEDs..............................................................................................................................24
4.4 UL notice .........................................................................................................................................25
5 Commissioning/application notes.........................................................................................................26
5.1 Application notes.............................................................................................................................26
5.2 Notes on converters with RJ45 fiber-optic connection ....................................................................30
5.2.1 Principles of fiber-optic technology .................................................................................. 31
5.2.2 Notes on suitable optical fiber cables............................................................................... 36
5.2.3 Application with CU1521 and CU1521-0010.................................................................... 37
5.2.4 Connecting and disconnecting the fiber cable ................................................................. 38
5.3 Notes on converters with RJ45 POF connection ............................................................................40
5.3.1 Notes regarding suitable POF cables .............................................................................. 40
5.3.2 Connecting and disconnecting the POF cable ................................................................. 41
5.4 Notes regarding assembly of POF cables with the connector set ZS1090-0008............................43
6 Appendix..................................................................................................................................................47
6.1 Safety instructions and behavioral rules for Class 1 laser ..............................................................47
6.2 Firmware compatibility ....................................................................................................................48
6.3 Support and Service........................................................................................................................49

Table of contents
CU1521-xxxx, CU15614 Version: 2.5

Foreword
CU1521-xxxx, CU1561 5Version: 2.5
1 Foreword
1.1 CU15x1 - Product overview
CU1521 [}16] - EtherCAT media converter multimode fiber optic
CU1521-0010 [}16] - EtherCAT media converter singlemode fiber optic
CU1561 [}16] - EtherCAT media converter fiber optic (POF)

Foreword
CU1521-xxxx, CU15616 Version: 2.5
1.2 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
CU1521-xxxx, CU1561 7Version: 2.5
1.3 Guide through documentation
NOTICE
Further components of documentation
This documentation describes device-specific content. It is part of the modular
documentation concept for Beckhoff I/O components. For the use and safe operation of the
device / devices described in this documentation, additional cross-product descriptions are
required, which can be found in the following table.
Title Description
EtherCAT System Documentation (PDF)• System overview
• EtherCAT basics
• Cable redundancy
• Hot Connect
• EtherCAT devices configuration
The documentations can be viewed at and downloaded from the Beckhoff website (www.beckhoff.com) via:
• the “Documentation and Download” area of the respective product page,
• the Download finder,
• the Beckhoff Information System.

Foreword
CU1521-xxxx, CU15618 Version: 2.5
1.4 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.
NOTICE
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
CU1521-xxxx, CU1561 9Version: 2.5
1.5 Documentation issue status
Version Modifications
2.5 • Update chapter “Commissioning”
• Update structure
2.4 • Update chapter “Notes on converters with RJ45 fiber-optic connection”
• Update structure
2.3 • Update chapter “Commissioning”
• Update Technical Data
• Update structure
2.2 • Update Technical Data
• Update structure
2.1 • Update Technical Data
• Update structure
2.0 • Migration
1.2 • Update chapter "Technical data"
1.1 • Update chapter "Application notes"
1.0 • Addenda and 1st public issue
0.3 • Addenda
0.2 • Addenda
0.1 • Preliminary version

Foreword
CU1521-xxxx, CU156110 Version: 2.5
1.6 Version identification of EtherCAT devices
1.6.1 General notes on marking
Designation
A Beckhoff EtherCAT device has a 14-digit designation, made up of
• family key
• type
• version
• revision
Example Family Type Version Revision
EL3314-0000-0016 EL terminal
12 mm, non-pluggable connection level
3314
4-channel thermocouple terminal
0000
basic type
0016
ES3602-0010-0017 ES terminal
12 mm, pluggable connection level
3602
2-channel voltage measurement
0010
high-precision version
0017
CU2008-0000-0000 CU device 2008
8-port fast ethernet switch
0000
basic type
0000
Notes
• The elements mentioned above result in the technical designation. EL3314-0000-0016 is used in the
example below.
• EL3314-0000 is the order identifier, in the case of “-0000” usually abbreviated to EL3314. “-0016” is the
EtherCAT revision.
• The order identifier is made up of
- family key (EL, EP, CU, ES, KL, CX, etc.)
- type (3314)
- version (-0000)
• The revision -0016 shows the technical progress, such as the extension of features with regard to the
EtherCAT communication, and is managed by Beckhoff.
In principle, a device with a higher revision can replace a device with a lower revision, unless specified
otherwise, e.g. in the documentation.
Associated and synonymous with each revision there is usually a description (ESI, EtherCAT Slave
Information) in the form of an XML file, which is available for download from the Beckhoff web site.
From 2014/01 the revision is shown on the outside of the IP20 terminals, see Fig. “EL5021 EL terminal,
standard IP20 IO device with batch number and revision ID (since 2014/01)”.
• The type, version and revision are read as decimal numbers, even if they are technically saved in
hexadecimal.

Foreword
CU1521-xxxx, CU1561 11Version: 2.5
1.6.2 Version identification of CU Switches
The serial number/ data code for Beckhoff IO devices is usually the 8-digit number printed on the device or
on a sticker. The serial number indicates the configuration in delivery state and therefore refers to a whole
production batch, without distinguishing the individual modules of a batch.
Structure of the serial number: KKYYFFHH
KK - week of production (CW, calendar week)
YY - year of production
FF - firmware version
HH - hardware version
Example with serial number 12 06 3A 02:
12 - production week 12
06 - production year 2006
3A - firmware version 3A
02 - hardware version 02
Fig.1: CU1521 switch with serial number 4820/ and the unique Beckhoff Traceability Number (BTN)
00007su0

Foreword
CU1521-xxxx, CU156112 Version: 2.5
1.6.3 Beckhoff Identification Code (BIC)
The Beckhoff Identification Code (BIC) is increasingly being applied to Beckhoff products to uniquely identify
the product. The BIC is represented as a Data Matrix Code (DMC, code scheme ECC200), the content is
based on the ANSI standard MH10.8.2-2016.
Fig.2: BIC as data matrix code (DMC, code scheme ECC200)
The BIC will be introduced step by step across all product groups.
Depending on the product, it can be found in the following places:
• on the packaging unit
• directly on the product (if space suffices)
• on the packaging unit and the product
The BIC is machine-readable and contains information that can also be used by the customer for handling
and product management.
Each piece of information can be uniquely identified using the so-called data identifier
(ANSIMH10.8.2-2016). The data identifier is followed by a character string. Both together have a maximum
length according to the table below. If the information is shorter, spaces are added to it.
Following information is possible, positions 1 to 4 are always present, the other according to need of
production:

Foreword
CU1521-xxxx, CU1561 13Version: 2.5
Posi-
tion
Type of
information
Explanation Data
identifier
Number of digits
incl. data identifier
Example
1 Beckhoff order
number
Beckhoff order number 1P 8 1P072222
2 Beckhoff Traceability
Number (BTN)
Unique serial number,
see note below
SBTN 12 SBTNk4p562d7
3 Article description Beckhoff article
description, e.g.
EL1008
1K 32 1KEL1809
4 Quantity Quantity in packaging
unit, e.g. 1, 10, etc.
Q 6 Q1
5 Batch number Optional: Year and week
of production
2P 14 2P401503180016
6 ID/serial number Optional: Present-day
serial number system,
e.g. with safety products
51S 12 51S678294
7 Variant number Optional: Product variant
number on the basis of
standard products
30P 32 30PF971, 2*K183
...
Further types of information and data identifiers are used by Beckhoff and serve internal processes.
Structure of the BIC
Example of composite information from positions 1 to 4 and with the above given example value on position
6. The data identifiers are highlighted in bold font:
1P072222SBTNk4p562d71KEL1809 Q1 51S678294
Accordingly as DMC:
Fig.3: Example DMC 1P072222SBTNk4p562d71KEL1809 Q1 51S678294
BTN
An important component of the BIC is the Beckhoff Traceability Number (BTN, position 2). The BTN is a
unique serial number consisting of eight characters that will replace all other serial number systems at
Beckhoff in the long term (e.g. batch designations on IO components, previous serial number range for
safety products, etc.). The BTN will also be introduced step by step, so it may happen that the BTN is not yet
coded in the BIC.
NOTICE
This information has been carefully prepared. However, the procedure described is constantly being further
developed. We reserve the right to revise and change procedures and documentation at any time and
without prior notice. No claims for changes can be made from the information, illustrations and descriptions
in this information.

Foreword
CU1521-xxxx, CU156114 Version: 2.5
1.6.4 Electronic access to the BIC (eBIC)
Electronic BIC (eBIC)
The Beckhoff Identification Code (BIC) is applied to the outside of Beckhoff products in a visible place. If
possible, it should also be electronically readable.
Decisive for the electronic readout is the interface via which the product can be electronically addressed.
K-bus devices (IP20, IP67)
Currently, no electronic storage and readout is planned for these devices.
EtherCAT devices (IP20, IP67)
All Beckhoff EtherCAT devices have a so-called ESI-EEPROM, which contains the EtherCAT identity with
the revision number. Stored in it is the EtherCAT slave information, also colloquially known as ESI/XML
configuration file for the EtherCAT master. See the corresponding chapter in the EtherCAT system manual
(Link) for the relationships.
The eBIC is also stored in the ESI‑EEPROM. The eBIC was introduced into the Beckhoff I/O production
(terminals, boxmodules) from 2020; widespread implementation is expected in 2021.
The user can electronically access the eBIC (if existent) as follows:
• With all EtherCAT devices, the EtherCAT master (TwinCAT) can read the eBIC from the ESI‑EEPROM
◦ From TwinCAT 3.1 build 4024.11, the eBIC can be displayed in the online view.
◦ To do this,
check the checkbox "Show Beckhoff Identification Code (BIC)" under
EtherCAT→AdvancedSettings→Diagnostics:
◦ The BTN and its contents are then displayed:
◦ Note: as can be seen in the illustration, the production data HW version, FW version and
production date, which have been programmed since 2012, can also be displayed with "Show
Production Info".
◦ From TwinCAT 3.1. build 4024.24 the functions FB_EcReadBIC and FB_EcReadBTN for reading
into the PLC and further eBIC auxiliary functions are available in the Tc2_EtherCAT Library from
v3.3.19.0.
• In the case of EtherCAT devices with CoE directory, the object 0x10E2:01 can additionally by used to
display the device's own eBIC; the PLC can also simply access the information here:

Foreword
CU1521-xxxx, CU1561 15Version: 2.5
◦ The device must be in PREOP/SAFEOP/OP for access:
◦ the object 0x10E2 will be introduced into stock products in the course of a necessary firmware
revision.
◦ From TwinCAT 3.1. build 4024.24 the functions FB_EcCoEReadBIC and FB_EcCoEReadBTN for
reading into the PLC and further eBIC auxiliary functions are available in the Tc2_EtherCAT
Library from v3.3.19.0.
• Note: in the case of electronic further processing, the BTN is to be handled as a string(8); the identifier
"SBTN" is not part of the BTN.
• Technical background
The new BIC information is additionally written as a category in the ESI‑EEPROM during the device
production. The structure of the ESI content is largely dictated by the ETG specifications, therefore the
additional vendor-specific content is stored with the help of a category according to ETG.2010. ID03
indicates to all EtherCAT masters that they must not overwrite these data in case of an update or
restore the data after an ESI update.
The structure follows the content of the BIC, see there. This results in a memory requirement of
approx. 50..200bytes in the EEPROM.
• Special cases
◦ If multiple, hierarchically arranged ESCs are installed in a device, only the top-level ESC carries
the eBIC Information.
◦ If multiple, non-hierarchically arranged ESCs are installed in a device, all ESCs carry the eBIC
Information.
◦ If the device consists of several sub-devices with their own identity, but only the top-level device is
accessible via EtherCAT, the eBIC of the top-level device is located in the CoE object directory
0x10E2:01 and the eBICs of the sub-devices follow in 0x10E2:nn.
Profibus/Profinet/DeviceNet… Devices
Currently, no electronic storage and readout is planned for these devices.

Product overview
CU1521-xxxx, CU156116 Version: 2.5
2 Product overview
2.1 Introduction
Fig.4: CU1561, CU1521
The EtherCAT-capable CU1521, CU1521-0010 and CU1561 devices should be used as media converter for
industrial fast Ethernet/100 Mbaud from optical fiber to copper and vice versa.
Fig.5: Upper picture: one media converter, copper -> fiber optic,
Lower picture: two media converters, copper -> fiber optic -> copper
From the physical layer perspective the CU1521 is suitable for multimode, while the CU1521-0010 is suitable
for single mode optical fiber and therefore for significantly longer transmission links up to 20 km.
The CU1561 is used for interfacing with POF (plastic optical fiber), which are suitable for small-scale
machine installation thanks to relatively inexpensive cable material and field-configurability.
The media converter operates bidirectionally and collision-free. The CU15x1 devices are therefore also
suitable as media converters for any Ethernet traffic. They support "Link Loss Forwarding", which means
that, if the link fails at the outgoing strand, for example due to a broken wire, the link is also withdrawn from
the incoming line, so that the sending device is notified of the link loss.
The CU15x1 devices are characterized by the fact that they support the requirements of an EtherCAT
network for a converter particularly well. This includes fast link control (establishment and disconnection),
diagnosis of communication errors, constant frame deceleration and readable identity (no transparent
operation). If the CU15x1 is set to EtherCAT mode with the rotary switch, it can be diagnosed as a separate
EtherCAT device. Hence, as opposed to standard media converters, he also ensures fast link control and
thus the secure termination of an EtherCAT strand even in the event of a disruption. Since the transfer
direction (copper Þ optical fiber or optical fibers Þ copper) is relevant for the EtherCAT bus, the operating
direction can be configured via the rotary switch.

Product overview
CU1521-xxxx, CU1561 17Version: 2.5
The CU15x1 are useful in applications where EtherCAT transfers over large distances are required or where
higher EMC loads on the bus line are to be expected.
Quick links
• EtherCAT basics
• Application notes [}26]
• Diagnostic LEDs [}24]

Product overview
CU1521-xxxx, CU156118 Version: 2.5
2.2 Technical data
Technical data CU1521 CU1521-0010 CU1561
Function Ethernet "IP" Media converter Fast Ethernet/100Mbaud (all IEEE 802.3-based
protocols)
IEEE 802.3u auto negotiation, half or full duplex, automatic settings
Link Loss-Forwarding (notification direction configurable)
Store and Forward Mode (FIFO)
unmanaged
Function EtherCAT "EC" Media converter Fast Ethernet/100Mbaud
Cut-through mode
Port handling/link control
Number of Ethernet ports 2
Ethernet interface X1 100BASE-FX
multimode glass fiber
50/125µm (MM)
typically 1300nm
1 x SC Duplex
100BASE-FX single
mode glass fiber
9/125µm (SM)
typically 1300nm
1 x SC Duplex
100BASE-FX-POF
glass fiber 980/1000
µm (POF);
typically 650nm
1 x versatile link for
POF duplex connector
(connector set
ZS1090-0008)
Laser class 1, see note
[}47]
Ethernet interface X2 10BASE-T/100BASE-TX Ethernet/EtherCAT cable (min. CAT 5),
screened
RJ45
Cable length X1 max. max. 2km (100BASE-
FX)
max. 20km (100BASE-
FX)
max. 50m (100BASE-
FX-POF)
Cable length X2 max. up to 100m twisted pair CAT5 (e)
Diagnostics LED: Supply voltage, link/activity X1/X2
EtherCAT: CRC
Power supply via three-pole spring loaded terminal (+, -, PE)
Supply voltage 24VDC (18VDC to 30VDC), protected against polarity reversal.
Current consumption typ. 95mA typ. 80mA typ. 60mA
Weight approx. 105g
Dimensions without plugs (W x H
x D)
approx. 34mm x 98mm x 77mm
Mounting [}23] on 35 mm mounting rail (mounting rail according to EN 60715)
Permissible ambient temperature
range during operation
-25°C ... +60°C
(extended temperature
range)
0°C …+55°C
Permissible ambient temperature
range during storage
-40°C ... +85°C -25°C ... +85°C
Permissible relative humidity 95%, no condensation
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
Marking / Approval*) CE, UKCA
cULus [}25]
*) Real applicable approvals/markings see type plate on the side (product marking).

Basic principles
CU1521-xxxx, CU1561 19Version: 2.5
3 Basic principles
3.1 EtherCAT basics
Please refer to the EtherCAT System Documentation for the EtherCAT fieldbus basics.
3.2 EtherCAT cabling – wire-bound
The cable length between two EtherCAT devices must not exceed 100 m. This results from the FastEthernet
technology, which, above all for reasons of signal attenuation over the length of the cable, allows a maximum
link length of 5 + 90 + 5 m if cables with appropriate properties are used. See also the Design
recommendations for the infrastructure for EtherCAT/Ethernet.
Cables and connectors
For connecting EtherCAT devices only Ethernet connections (cables + plugs) that meet the requirements of
at least category 5 (CAt5) according to EN 50173 or ISO/IEC 11801 should be used. EtherCAT uses 4 wires
for signal transfer.
EtherCAT uses RJ45 plug connectors, for example. The pin assignment is compatible with the Ethernet
standard (ISO/IEC 8802-3).
Pin Color of conductor Signal Description
1 yellow TD + Transmission Data +
2 orange TD - Transmission Data -
3 white RD + Receiver Data +
6 blue RD - Receiver Data -
Due to automatic cable detection (auto-crossing) symmetric (1:1) or cross-over cables can be used between
EtherCAT devices from Beckhoff.
Recommended cables
It is recommended to use the appropriate Beckhoff components e.g.
- cable sets ZK1090-9191-xxxx respectively
- RJ45 connector, field assembly ZS1090-0005
- EtherCAT cable, field assembly ZB9010, ZB9020
Suitable cables for the connection of EtherCAT devices can be found on the Beckhoff website!
E-Bus supply
A bus coupler can supply the EL terminals added to it with the E-bus system voltage of 5V; a coupler is
thereby loadable up to 2A as a rule (see details in respective device documentation).
Information on how much current each EL terminal requires from the E-bus supply is available online and in
the catalogue. If the added terminals require more current than the coupler can supply, then power feed
terminals (e.g. EL9410) must be inserted at appropriate places in the terminal strand.
The pre-calculated theoretical maximum E-Bus current is displayed in the TwinCAT System Manager. A
shortfall is marked by a negative total amount and an exclamation mark; a power feed terminal is to be
placed before such a position.

Basic principles
CU1521-xxxx, CU156120 Version: 2.5
Fig.6: System manager current calculation
NOTICE
Malfunction possible!
The same ground potential must be used for the E-Bus supply of all EtherCAT terminals in a terminal block!
3.3 EtherCAT State Machine
The state of the EtherCAT slave is controlled via the EtherCAT State Machine (ESM). Depending upon the
state, different functions are accessible or executable in the EtherCAT slave. Specific commands must be
sent by the EtherCAT master to the device in each state, particularly during the bootup of the slave.
A distinction is made between the following states:
• Init
• Pre-Operational
• Safe-Operational and
• Operational
• Boot
The regular state of each EtherCAT slave after bootup is the OP state.
Fig.7: States of the EtherCAT State Machine