Beckhoff EL7031, EL7041-1000, EL7041-0000, EL7041-0001 Documentation
Documentation
EL70x1
Stepper Motor Terminals
4.4
2017-08-18
Version:
Date:
Table of contents
EL70x1 3Version: 4.4
Table of contents
1 Foreword ....................................................................................................................................................7
1.1 Product overview Stepper motor terminals..................................................................................... 7
1.2 Notes on the documentation........................................................................................................... 7
1.3 Safety instructions .......................................................................................................................... 9
1.4 Documentation issue status.......................................................................................................... 10
1.5 Version identification of EtherCAT devices................................................................................... 11
1.6 Non-reactive Bus Terminals ......................................................................................................... 15
2 Product overview.....................................................................................................................................16
2.1 EL7031 - Introduction ................................................................................................................... 16
2.2 EL7031 - Technical data............................................................................................................... 18
2.3 EL7041 - Introduction ................................................................................................................... 19
2.4 EL7041-x00x - Technical data ...................................................................................................... 22
2.5 Technology ................................................................................................................................... 23
3 Basics communication ...........................................................................................................................27
3.1 EtherCAT basics........................................................................................................................... 27
3.2 EtherCAT cabling – wire-bound.................................................................................................... 27
3.3 General notes for setting the watchdog ........................................................................................ 28
3.4 EtherCAT State Machine .............................................................................................................. 30
3.5 CoE Interface................................................................................................................................ 32
3.6 Distributed Clock........................................................................................................................... 37
4 Mounting and wiring ...............................................................................................................................38
4.1 Installation on mounting rails ........................................................................................................ 38
4.2 Installation instructions for enhanced mechanical load capacity .................................................. 40
4.3 Connection.................................................................................................................................... 41
4.3.1 Connection system...........................................................................................................41
4.3.2 Wiring...............................................................................................................................43
4.3.3 Shielding ..........................................................................................................................44
4.4 Mounting of Passive Terminals..................................................................................................... 44
4.5 Installation position for operation with or without fan .................................................................... 45
4.6 UL notice - Compact Motion ......................................................................................................... 49
4.7 EL7031 ......................................................................................................................................... 51
4.7.1 LEDs and connection.......................................................................................................51
4.7.2 General connection examples .........................................................................................52
4.8 EL7041 ......................................................................................................................................... 54
4.8.1 LEDs and connection.......................................................................................................54
4.8.2 General connection examples .........................................................................................66
5 Commissioning........................................................................................................................................68
5.1 TwinCAT Quick Start .................................................................................................................... 68
5.1.1 TwinCAT2 .......................................................................................................................70
5.1.2 TwinCAT 3 .......................................................................................................................80
5.2 TwinCAT Development Environment............................................................................................ 92
5.2.1 Installation of the TwinCAT real-time driver .....................................................................92
5.2.2 Notes regarding ESI device description...........................................................................98
5.2.3 TwinCAT ESI Updater....................................................................................................102
5.2.4 Distinction between Online and Offline ..........................................................................102
5.2.5 OFFLINE configuration creation ....................................................................................103
Table of contents
EL70x14 Version: 4.4
5.2.6 ONLINE configuration creation ......................................................................................108
5.2.7 EtherCAT subscriber configuration ................................................................................116
5.3 General Notes - EtherCAT Slave Application ............................................................................. 126
5.4 Integration into the NC configuration .......................................................................................... 135
5.5 Configuration of the main parameters ........................................................................................ 139
5.6 Basic principles for the Positioning Interface .............................................................................. 146
5.6.1 Predefined PDO Assignment .........................................................................................147
5.6.2 Parameter set.................................................................................................................147
5.6.3 Information and diagnostic data.....................................................................................149
5.6.4 States of the internal state machine...............................................................................150
5.6.5 Standard sequence of a travel command ......................................................................150
5.6.6 Start types......................................................................................................................151
5.6.7 Modulo - general description..........................................................................................155
5.6.8 Examples of two travel commands with a dynamic change of the target position ......... 159
5.7 Process data............................................................................................................................... 161
5.7.1 Sync Manager (SM) .......................................................................................................161
5.7.2 PDO Assignment............................................................................................................162
5.7.3 Predefined PDO Assignment .........................................................................................165
5.8 Application example.................................................................................................................... 166
5.9 EL7031 - Object description and parameterization..................................................................... 171
5.9.1 Restore object................................................................................................................171
5.9.2 Configuration data..........................................................................................................171
5.9.3 Command object............................................................................................................176
5.9.4 Input data .......................................................................................................................177
5.9.5 Output data ....................................................................................................................178
5.9.6 Information / diagnostic data (channel specific).............................................................182
5.9.7 Vendor configuration data (device-specific)...................................................................183
5.9.8 Information / diagnostic data (device-specific)...............................................................184
5.9.9 Standard objects ............................................................................................................184
5.10 EL7041 - Object description and parameterization..................................................................... 195
5.10.1 Restore object ................................................................................................................195
5.10.2 Configuration data..........................................................................................................195
5.10.3 Command object ............................................................................................................200
5.10.4 Input data .......................................................................................................................201
5.10.5 Output data ....................................................................................................................202
5.10.6 Information / diagnostic data (channel specific) .............................................................205
5.10.7 Vendor configuration data (device-specific) ...................................................................206
5.10.8 Information / diagnostic data (device-specific) ...............................................................207
5.10.9 Standard objects ............................................................................................................207
5.11 EL7041-1000 - Object description and parameterisation ........................................................... 219
5.11.1 Restore object ................................................................................................................219
5.11.2 Configuration data..........................................................................................................219
5.11.3 Command object ............................................................................................................221
5.11.4 Input data .......................................................................................................................222
5.11.5 Output data ....................................................................................................................222
5.11.6 Information / diagnostic data (channel specific) .............................................................223
5.11.7 Vendor configuration data (device-specific) ...................................................................224
5.11.8 Information / diagnostic data (device-specific) ...............................................................224
5.11.9 Standard objects ............................................................................................................224
6 Diagnosis - Diag Messages ..................................................................................................................233
6.1 Definition..................................................................................................................................... 233
6.2 TwinCAT System Manager implementation ............................................................................... 234
6.3 Interpretation............................................................................................................................... 234
Table of contents
EL70x1 5Version: 4.4
7 Appendix ................................................................................................................................................237
7.1 EtherCAT AL Status Codes ........................................................................................................ 237
7.2 Firmware compatibility ................................................................................................................ 237
7.3 Firmware Update EL/ES/EM/EPxxxx.......................................................................................... 239
7.4 Restoring the delivery state ........................................................................................................ 249
7.5 Support and Service ................................................................................................................... 250
Table of contents
EL70x16 Version: 4.4
Foreword
EL70x1 7Version: 4.4
1 Foreword
1.1 Product overview Stepper motor terminals
EL7031 [}16],
Stepper motor terminal, 24 VDC, 1.5 A
EL7041-x00x [}19]
Stepper motor terminal, 50 VDC, 5 A, with incremental encoder
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®, EtherCAT®, Safety over EtherCAT®, TwinSAFE®, XFC® and XTS® 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, DE102004044764, DE102007017835 with corresponding applications or
registrations in various other countries.
The TwinCAT Technology is covered, including but not limited to the following patent applications and
patents: EP0851348, US6167425 with corresponding applications or registrations in various other countries.
EtherCAT® is registered trademark and patented technology, licensed by Beckhoff Automation GmbH,
Germany
Foreword
EL70x18 Version: 4.4
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
EL70x1 9Version: 4.4
1.3 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 symbols
In this documentation the following symbols are used with an accompanying safety instruction or note. The
safety instructions must be read carefully and followed without fail!
DANGER
Serious risk of injury!
Failure to follow the safety instructions associated with this symbol directly endangers the
life and health of persons.
WARNING
Risk of injury!
Failure to follow the safety instructions associated with this symbol endangers the life and
health of persons.
CAUTION
Personal injuries!
Failure to follow the safety instructions associated with this symbol can lead to injuries to
persons.
Attention
Damage to the environment or devices
Failure to follow the instructions associated with this symbol can lead to damage to the environment or equipment.
Note
Tip or pointer
This symbol indicates information that contributes to better understanding.
Foreword
EL70x110 Version: 4.4
1.4 Documentation issue status
Version Comment
4.4 - Update chapter “Technical data”
- Update revision status
- Update structure
4.3 - Update chapter “Technical data”
- Update chapter „UL Hinweise – Compact Motion“ ergänzt
- Update chapter "Object description"
- Update chapter "Process data"
- Update revision status
- Update structure
4.2 - Update chapter “Technical data”
- Update revision status
- Update structure
4.1 - Update chapter “LEDs and connection”
- Update revision status
- Update structure
4.0 - Migration
- Update revision status
- Update structure
3.2 - Update chapter "Object description"
- Update chapter "Basic principles: Positioning interface"
- Update chapter "Process data"
- Update structure
- Update revision status
3.1 - Update Section "LEDs and connection"
- Update structure
- Update revision status
3.0 - Update chapter "Technical data"
- Addenda chapter "Installation instructions for enhanced mechanical load capacity"
- Update structure
- Update revision status
2.9 - Update chapter "Technical data" and "Object description"
- Update firmware status
2.8 - Update chapter "Technical data"
- Update firmware status
2.7 - Update chapter "Technical data" and "Object description"
- Update firmware status
2.6 - Update chapter "Technical data"
- Update firmware status
2.5 - Update chapter "Technical data"
- Update firmware status
2.4 - Update chapter "Technical data"
- Update firmware status
2.3 - Update chapter "Technology"
- Update firmware status
2.2 - Update object description
- Update firmware status
2.1 - Update structure
- Addenda chapter "TwinCAT 2.1x"
2.0 - Addenda Process data
- Addenda "Basics positioning interface"
1.5 - Addenda CoE objects
1.4 - Addenda: object description, technical description added
1.3 - Addenda: object description, technical description added
1.2 - Technical data & object description added
1.1 - Addenda CoE objects, EL7041-0001 added
1.0 - Corrections, 1st public issue
0.2 - 0.5 - Corrections and addenda
0.1 - Preliminary documentation for EL70x1
Foreword
EL70x1 11Version: 4.4
1.5 Version identification of EtherCAT devices
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, nonpluggable 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 (highprecision 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.
Identification number
Beckhoff EtherCAT devices from the different lines have different kinds of identification numbers:
Production lot/batch number/serial number/date code/D number
The serial number 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: KKYYFFHH
KK - week of production (CW, calendar week)
YY - year of production
FF - firmware version
HH - hardware version
Foreword
EL70x112 Version: 4.4
Example with
Ser. no.: 12063A02: 12 - production week 12 06 - production year 2006 3A - firmware version 3A 02 hardware version 02
Exceptions can occur in the IP67 area, where the following syntax can be used (see respective device
documentation):
Syntax: D ww yy x y z u
D - prefix designation
ww - calendar week
yy - year
x - firmware version of the bus PCB
y - hardware version of the bus PCB
z - firmware version of the I/O PCB
u - hardware version of the I/O PCB
Example: D.22081501 calendar week 22 of the year 2008 firmware version of bus PCB: 1 hardware version
of bus PCB: 5 firmware version of I/O PCB: 0 (no firmware necessary for this PCB) hardware version of I/O
PCB: 1
Unique serial number/ID, ID number
In addition, in some series each individual module has its own unique serial number.
See also the further documentation in the area
• IP67: EtherCAT Box
• Safety: TwinSafe
• Terminals with factory calibration certificate and other measuring terminals
Examples of markings
Fig.1: EL5021 EL terminal, standard IP20 IO device with batch number and revision ID (since 2014/01)
Foreword
EL70x1 13Version: 4.4
Fig.2: EK1100 EtherCAT coupler, standard IP20 IO device with batch number
Fig.3: CU2016 switch with batch number
Fig.4: EL3202-0020 with batch numbers 26131006 and unique ID-number 204418
Foreword
EL70x114 Version: 4.4
Fig.5: EP1258-00001 IP67 EtherCAT Box with batch number 22090101 and unique serial number 158102
Fig.6: EP1908-0002 IP67 EtherCAT Safety Box with batch number 071201FF and unique serial number
00346070
Fig.7: EL2904 IP20 safety terminal with batch number/date code 50110302 and unique serial number
00331701
Fig.8: ELM3604-0002 terminal with ID number (QR code) 100001051 and unique serial number 44160201
Foreword
EL70x1 15Version: 4.4
1.6 Non-reactive Bus Terminals
Note
Use of non-reactive Bus Terminals in safety applications
If a Bus Terminal is described as non-reactive, this means that the downstream terminal
behaves passively in a safety application (e.g. in the case of the all-pole switch-off of a potential group).
In this case the terminals do not represent an active part of the safety controller and do not
affect the Safety Integrity Level (SIL) or Performance Level (PL) attained in the safety application.
For details, please refer to chapter 2.17f in the TwinSAFE application manual.
Attention
Pay attention to the hardware version
Please pay attention to the information about the hardware version and non-reactivity of the
respective Bus Terminal in the chapters "Technical Data" or "Firmware Compatibility"!
Only terminals with the appropriate hardware version may be used without the attained SIL/
PL being affected!
The following tables show the designated non-reactive Bus or EtherCAT terminals at the time of the
preparation of this documentation with the corresponding hardware status
Bus terminal designation Hardware status
KL2408 05 - 07
KL2809 02
KL2134 09
KL2424 05
EtherCAT terminal designation Hardware status
EL2004 15 - 21
EL2008 07 - 13
EL2024 06 - 11
EL2034 06 - 07
EL2809 01 - 07
EL2872 01 - 07
EL7031 02 - 11
Product overview
EL70x116 Version: 4.4
2 Product overview
2.1 EL7031 - Introduction
Fig.9: EL7031
Stepper motor terminal, 24 VDC, 1.5 A
The EL7031 EtherCAT Terminal is intended for the direct connection of different small stepper motors. The
slimline PWM output stages for two motor coils are located in the EtherCAT Terminal together with two
inputs for limit switches. The EL7031 can be adjusted to the motor and the application by changing just a few
parameters. 64-fold micro-stepping ensures particularly quiet and precise motor operation.
Quick links
Connection instructions
• Chapter "Mounting and wiring",
◦ LEDs and connection [}51]
◦ Connection examples [}52]
Commissioning instructions
• Chapter "Commissioning",
◦ Installation under TwinCAT [}92]
◦ Integration into the NC configuration [}135]
◦ Basic principles: "Positioning interface" [}146]
Configuration instructions
• Chapter "Commissioning",
◦ Configuration of the main parameters
Product overview
EL70x1 17Version: 4.4
• Chapter "Configuration with the TwinCAT System Manager",
◦ Object description and parameterization [}171]
Application example
• Chapter "Commissioning",
◦ Application example [}166]
Product overview
EL70x118 Version: 4.4
2.2 EL7031 - Technical data
Technical data EL7031
Number of outputs 1 stepper motor, 2 phases
Power supply for output stage (via power contacts) 24VDC (-15% / +20%)
Non-reactive outputs
yes (see notice [}15])
Number of inputs 2
Supply voltage 24VDC via the power contacts, via the E-bus
Output current 1.5 A (overload- and short-circuit-proof)
Maximum step frequency 1000, 2000, 4000 or 8000 full steps/s (configurable)
Step pattern full step, half step, up to 64-fold micro stepping
Current controller frequency approx. 25 kHz
Input signal voltage "0" -3V … 2V
Input signal voltage "1" 2.5V … 28V
Input current typ. 5mA
Diagnostic LED error phase A and B, loss of step/stagnation, power, enable
Resolution approx. 5,000 positions in typical applications (per revolution)
Power supply via the E-bus, encoder/driver stage/motor: via the power contacts
Current consumption via E-bus typ. 120 mA
Electrical isolation 500 V (E-bus/signal voltage)
Supports NoCoeStorage [}32] function
from firmware 04
Configuration no address setting required
configuration via TwinCAT System Manager
Weight approx. 105 g
Permissible ambient temperature range during operation 0°C ... + 55°C
Permissible ambient temperature range during storage -25°C ... + 85°C
Permissible relative humidity 95%, no condensation
Dimensions (W x H x D) approx. 15 mm x 100 mm x 70 mm (width aligned: 12 mm)
Mounting [}38]
on 35 mm mounting rail conforms to EN 60715
Vibration/shock resistance conforms to EN 60068-2-6 / EN 60068-2-27,
see also installation instructions [}40] for enhanced mechanical
load capacity
EMC immunity/emission conforms to EN 61000-6-2 / EN 61000-6-4
according to IEC/EN 61800-3
EMC category Category C3 - standard
Category C2, C1 - auxiliary filter required
Protection class IP20
Installation position
without fan cartridge ZB8610: standard installing position
with fan cartridge ZB8610: standard installing position, other installing
positions (example 1 & 2)
see notice [}45]
Approval CE
cULus [}49]
Product overview
EL70x1 19Version: 4.4
2.3 EL7041 - Introduction
Fig.10: EL7041-0000
Fig.11: EL7041-0001
Product overview
EL70x120 Version: 4.4
Fig.12: EL7041-1000
Stepper motor terminal, 50VDC, 5A, with incremental encoder
The EL7041-x00x EtherCAT Terminal is intended for stepper motors with medium performance range. The
PWM output stages cover a wide range of voltages and currents. Together with two inputs for limit switches,
they are located in the EtherCAT Terminal. The EL7041-x00x can be adjusted to the motor and the
application by changing just a few parameters. 64-fold micro-stepping ensures particularly quiet and precise
motor operation. Together with a stepper motor, the EL7041-x00x represents an inexpensive small servo
axis.
Quick links
Connection instructions
• Chapter "Mounting and wiring",
◦ LEDs and connection [}54]
◦ Connection examples [}66]
Commissioning instructions
• Chapter "Commissioning",
◦ Installation under TwinCAT [}92]
◦ Integration into the NC configuration [}135]
◦ Basic principles: "Positioning interface" [}146]
Configuration instructions
• Chapter "Commissioning",
◦ Configuration of the main parameters
• Chapter "Configuration with the TwinCAT System Manager",
◦ Object description and parameterization [}195] (EL7041-0000, EL7041-0001)
◦ Object description and parameterization [}219] (EL7041-1000)
Product overview
EL70x1 21Version: 4.4
Application example
• Chapter "Commissioning",
◦ Application example [}166]
Product overview
EL70x122 Version: 4.4
2.4 EL7041-x00x - Technical data
Technical data EL7041-0000 EL7041-0001 EL7041-1000
Number of outputs 1 stepper motor, 2 phases
Number of digital inputs 2 limit position, 4 for an en-
coder system
1 limit position, 4 for an encoder system
2 limit position, 4 for an encoder system
Number of digital outputs - 1 output, 24 VDC; 0.5 A
(configurable as a brake
[}197])
-
Supply voltage 8 … 50V
DC
Output current 5 A (overload- and short-circuit-proof)
Maximum step frequency 1000, 2000, 4000, 8000, 16000, 32000 full steps/s (configurable)
Step pattern up to 64-fold micro stepping (automatic switching, speed-dependent)
Current controller frequency approx. 30 kHz
Encoder pulse frequency maximum 400,000 increments/s (4-fold evaluation)
Input signal voltage "0" -3V … 2V
Input signal voltage "1" 2.5V … 28V
Input current typ. 5 mA
Diagnostic LED Warning strand A and B, error strand A and B, power, enable
Resolution approx. 5,000 positions in typical applications (per revolution)
Power supply via the E-bus, encoder/driver stage: via the power contacts, motor: via terminal contacts
Current consumption via E-bus typ. 140 mA
Electrical isolation 500 V (E-bus/signal voltage)
Configuration no address setting required
configuration via TwinCAT System Manager
Supports NoCoeStorage [}32] function
from firmware 05 from firmware 02
Weight approx. 105 g
Permissible ambient temperature range
during operation
0°C ... + 55°C
Permissible ambient temperature range
during storage
-25°C ... + 85°C
Permissible relative humidity 95%, no condensation
Dimensions (W x H x D) approx. 27 mm x 100 mm x 70 mm (width aligned: 24 mm)
Mounting [}38]
on 35 mm mounting rail conforms to EN 60715
Vibration/shock resistance conforms to EN 60068-2-6 / EN 60068-2-27,
see also installation instructions [}40] for enhanced mechanical load capacity
EMC immunity/emission conforms to EN 61000-6-2 / EN 61000-6-4
according to IEC/EN 61800-3
EMC category Category C3 - standard
Category C2, C1 - auxiliary filter required
Protection class IP20
Installation position
without fan cartridge ZB8610: standard installing position
with fan cartridge ZB8610: standard installing position, other installing positions (example 1
& 2)
see notice [}45]
Approval CE
cULus [}49]
CE CE
cULus [}49]
Product overview
EL70x1 23Version: 4.4
2.5 Technology
The EL7031 and EL7041 Stepper Motor terminals integrate a compact Motion Control solution for stepper
motors up to 200W in a compact unit.
Stepper motor
Stepper motors are electric motors and are comparable with synchronous motors. The rotor is designed as a
permanent magnet, while the stator consists of a coil package. In contrast to synchronous motors, stepper
motors have a large number of pole pairs. In a minimum control configuration, the stepper motor is moved
from pole to pole, or from step to step.
Stepper motors have been around for many years. They are robust, easy to control, and provide high torque.
In many applications, the step counting facility saves expensive feedback systems. Even with the
increasingly widespread use of synchronous servomotors, stepper motors are by no means "getting long in
the tooth". They are considered to represent mature technology and continue to be developed further in
order to reduce costs and physical size, increase torque and improve reliability.
The development of the EL7031 and EL7041 EtherCAT Terminals for the Beckhoff EtherCAT Terminal
system opens up new application areas. Microstepping and the latest semiconductor technology offer many
advantages:
• smoother operation
• avoidance of resonance
• reduced energy consumption
• lower thermal load on the motor
• minimum electromagnetic emissions
• long cable lengths
• simpler handling
• reduced size of the power electronics
• simple integration into higher-level systems
• integrated feedback system
Two stepper motor terminals for optimum performance
The EL7031 and EL7041 Stepper Motor terminals differ in terms of performance.
EL7031
With a size of only 12 mm, the EL7031 [}16] covers the lower performance range. The supply voltage can be
up to 24 VDC. The device is designed for simple integration into the 24 VDC control voltage system. With a
peak current of 1.5 A per phase, a large number of small drives and axes can be supplied.
EL7041
The EL7041 [}19] offers higher performance comparable to that of small servo drives. With a peak current of
5 A, the EL7041 can generate an impressive torque of 5Nm in conjunction with a standard stepper motor,
for example. The supply voltage of up to 50 VDC enables high speeds with good torque and therefore high
mechanical output (up to about 200 W). The EL7041 has an integrated incremental encoder interface for
connecting all drive cables, although it is still only 24 mm wide.
Both stepper motor terminals provide two controlled sine/cosine currents. 25 kHz current control enables
smooth current output without resonance. Highly dynamic, low-inductance motors run just as well as stepper
motors with small rotor mass. The current resolution is 64 steps per period (64-fold microstepping). The
standard motor with a 1.8° step angle runs very smoothly and can be set to up to 12,800 electronic positions
per turn. Experience shows that approx, 5,000 positions are realistic in terms of the mechanics.
Product overview
EL70x124 Version: 4.4
Typical stepper motor problems such as pronounced resonance are therefore a thing of the past.
Microstepping and associated set values ensure that rotor jerk is avoided. Also, the rotor no longer tends to
oscillate around each indexing position. Mechanical measures such as vibration dampers against resonance
or gear reduction for increasing precision are no longer required. This allows the burden from costs and
development effort to be lower.
The new stepper motor terminals also reduce development time on the control side. Both Bus Terminals can
be used just like standard EtherCAT Terminalsin all common fieldbuses. Interface programming is therefore
no longer required. Start, stop or resonance frequencies are no longer an issue. For simple positioning tasks,
both EtherCAT Terminals can automatically position the drive, taking account of an acceleration ramp and
the maximum frequency.
Realization of more demanding positioning tasks
More demanding positioning tasks can be realized via the TwinCAT automation software from Beckhoff. Like
other axes, the two stepper motor terminals are integrated via the TwinCAT System Manager and can be
used like standard servo axes. Special stepper motor features, such as speed reduction in the event of large
following errors, are automatically taken into account via the stepper motor axis option. The effort for
changing from a servomotor to a stepper motor - and back - is no greater than changing from one fieldbus to
another one under TwinCAT.
The output stages of the stepper motor terminals have an overload protection in the form of an
overtemperature warning and switch-off. Together with short circuit detection, diagnostic data are accessible
in the process image of the controller. In addition, this status is displayed by the Bus Terminal LEDs, along
with other information. The output stage is switched on via an Enable-Bit. The motor current can be set and
reduced via a parameter value.
Optimum adaptation to the motor and the implementation of energy-saving features require minimum
programming effort. Since all data are set in the form of parameters in the CoE register, it is easily possible
to replace an EtherCAT Terminal or store certain parameters for transfer to the next project. It is therefore no
longer necessary to transfer certain potentiometer settings or to document DIP switch settings.
Stepper motor parameters
Torque
Refers to the maximum motor torque at different speeds. This parameter is usually represented by a
characteristic curve. Stepper motors have comparatively high torque in the lower speed range. In many
applications, this enables them to be used directly without gearing. Compared with other motors, stepper
motors can quite easily provide a holding moment of the same order of magnitude as the torque.
Speed
Stepper motors have low maximum speed, which is usually specified as a maximum step frequency.
Number of phases
Motors with 2 to 5 phases are common. The EL7031 and EL7041 EtherCAT Terminals support 2-phase
motors. 4-phase motors are basically 2-phase motors with separate winding ends. They can be connected
directly to the EtherCAT Terminal.
Nominal voltage, supply voltage and winding resistance
Under steady-state conditions, the rated current at the rated voltage depends on the winding resistance. This
voltage should not be confused with the supply voltage of the power output stage in the EtherCAT Terminal.
The EL7031 and EL7041 apply a controlled current to the motor winding. If the supply voltage falls below the
nominal voltage, the power output stage can no longer apply the full current, resulting in a loss of torque. It is
desirable to aim for systems with small winding resistance and high supply voltage in order to limit warming
and achieve high torque at high speeds.
Product overview
EL70x1 25Version: 4.4
Resonance
At certain speeds, stepper motors run less smoothly. This phenomenon is particularly pronounced if the
motor runs without load. Under certain circumstances, it may even stop. This is caused by resonance. A
distinction can roughly be made between
• resonances in the lower frequency range up to approx. 250Hz; and
• resonances in the medium to upper frequency range.
Resonances in the medium to upper frequency range essentially result from electrical parameters such as
inductance of the motor winding and supply line capacity. They can be controlled relatively easily through
high pulsing of the control system.
Resonances in the lower range essentially result from the mechanical motor parameters. Apart from their
impact on smooth running, such resonances can lead to significant loss of torque, or even loss of step of the
motor, and are therefore particularly undesirable.
In principle, the stepper motor represents an oscillatory system (comparable to a mass/spring system),
consisting of the moving rotor with a moment of inertia and a magnetic field that creates a restoring force that
acts on the rotor. Moving and releasing the rotor creates a damped oscillation. If the control frequency
corresponds to the resonance frequency, the oscillation is amplified, so that in the worst case the rotor will
no longer follow the steps, but oscillate between two positions.
Due to their sine/cosine current profile, EL7031 and EL7041 EtherCAT Terminals are able to prevent this
effect in almost all standard motors. The rotor is not moved from step to step, so he no longer jumps to the
next position, but it moves through 64 intermediate steps, i.e. the rotor is gently moved from one step to the
next. The usual loss of torque at certain speeds is avoided, and operation can be optimized for the particular
application. This means that the lower speed range, where particularly high torque is available, can be fully
utilized.
Step angle
The step angle indicates the angle travelled during each step. Typical values are 3.6°, 1.8° and 0.9°. This
corresponds to 100, 200 and 400 steps per motor revolution. Together with the downstream transmission
ratio, this value is a measure for the positioning accuracy. For technical reasons, the step angle cannot be
reduced below a certain value. Positioning accuracy can only be improved further by mechanical means
(transmission). An elegant solution for improving positioning accuracy is the microstepping function offered
by the EL7031 and EL7041. It enables up to 64 intermediate steps. The smaller "artificial" step angle has a
further positive effect: The drive can be operated at higher speed, yet with the same precision. The
maximum speed is unchanged, despite the fact that the drive operates at the limit of mechanical resolution.
Specifying the stepper motor
1. Determine the required positioning accuracy and hence the step resolution. The first task is to determine the maximum resolution that can be achieved. The resolution can be increased via mechanical
gear reduction devices such as spindles, gearing or toothed racks. The 64-fold microstepping of the
stepper motor terminals also has to be taken into account.
2. Determine mass m and moment of inertia (J) of all parts to be moved
3. Calculate the acceleration resulting from the temporal requirements of the moved mass.
4. Calculate the forces from mass, moment of inertia, and the respective accelerations.
5. Convert the forces and velocities to the rotor axis, taking account of efficiencies, moments of friction
and mechanical parameters such as gear ratio. It is often best to start the calculation from the last
component, usually the load. Each further element transfers a force and velocity and leads to further
forces or torques due to friction. During positioning, the sum of all forces and torques acts on the motor shaft. The result is a velocity/torque curve that the motor has to provide.
6. Using the characteristic torque curve, select a motor that meets these minimum requirements. The
moment of inertia of the motor has to be added to the complete drive. Verify your selection. In order to
provide an adequate safety margin, the torque should be oversized by 20% to 30%. The optimization
is different if the acceleration is mainly required for the rotor inertia. In this case, the motor should be
as small as possible.
7. Test the motor under actual application conditions: Monitor the housing temperatures during continuous operation. If the test results do not confirm the calculations, check the assumed parameters and
boundary conditions. It is important to also check side effects such as resonance, mechanical play,
settings for the maximum operation frequency and the ramp slope.
Product overview
EL70x126 Version: 4.4
8. Different measures are available for optimizing the performance of the drive: using lighter materials or
hollow instead of solid body, reducing mechanical mass. The control system can also have significant
influence on the behavior of the drive. The Bus Terminal enables operation with different supply voltages. The characteristic torque curve can be extended by increasing the voltage. In this case, a current increase factor can supply a higher torque at the crucial moment, while a general reduction of the
current can significantly reduce the motor temperature. For specific applications, it may be advisable
to use a specially adapted motor winding.
Basics communication
EL70x1 27Version: 4.4
3 Basics communication
3.1 EtherCAT basics
Please refer to the chapter 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.
Note
Recommended cables
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 5V; a coupler is
thereby loadable up to 2A 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.
Basics communication
EL70x128 Version: 4.4
Fig.13: System manager current calculation
Attention
Malfunction possible!
The same ground potential must be used for the E-Bus supply of all EtherCAT terminals in
a terminal block!
3.3 General notes for setting the watchdog
ELxxxx terminals are equipped with a safety feature (watchdog) that switches off the outputs after a
specifiable time e.g. in the event of an interruption of the process data traffic, depending on the device and
settings, e.g. in OFF state.
The EtherCAT slave controller (ESC) in the EL2xxx terminals features 2 watchdogs:
• SM watchdog (default: 100 ms)
• PDI watchdog (default: 100 ms)
SM watchdog (SyncManager Watchdog)
The SyncManager watchdog is reset after each successful EtherCAT process data communication with the
terminal. If no EtherCAT process data communication takes place with the terminal for longer than the set
and activated SM watchdog time, e.g. in the event of a line interruption, the watchdog is triggered and the
outputs are set to FALSE. The OP state of the terminal is unaffected. The watchdog is only reset after a
successful EtherCAT process data access. Set the monitoring time as described below.
The SyncManager watchdog monitors correct and timely process data communication with the ESC from the
EtherCAT side.
PDI watchdog (Process Data Watchdog)
If no PDI communication with the EtherCAT slave controller (ESC) takes place for longer than the set and
activated PDI watchdog time, this watchdog is triggered.
PDI (Process Data Interface) is the internal interface between the ESC and local processors in the EtherCAT
slave, for example. The PDI watchdog can be used to monitor this communication for failure.
The PDI watchdog monitors correct and timely process data communication with the ESC from the
application side.
The settings of the SM- and PDI-watchdog must be done for each slave separately in the TwinCAT System
Manager.
Basics communication
EL70x1 29Version: 4.4
Fig.14: EtherCAT tab -> Advanced Settings -> Behavior -> Watchdog
Notes:
• the multiplier is valid for both watchdogs.
• each watchdog has its own timer setting, the outcome of this in summary with the multiplier is a
resulting time.
• Important: the multiplier/timer setting is only loaded into the slave at the start up, if the checkbox is
activated.
If the checkbox is not activated, nothing is downloaded and the ESC settings remain unchanged.
Multiplier
Multiplier
Both watchdogs receive their pulses from the local terminal cycle, divided by the watchdog multiplier:
1/25 MHz * (watchdog multiplier + 2) = 100 µs (for default setting of 2498 for the multiplier)
The standard setting of 1000 for the SM watchdog corresponds to a release time of 100 ms.
The value in multiplier + 2 corresponds to the number of basic 40 ns ticks representing a watchdog tick.
The multiplier can be modified in order to adjust the watchdog time over a larger range.
Basics communication
EL70x130 Version: 4.4
Example "Set SM watchdog"
This checkbox enables manual setting of the watchdog times. If the outputs are set and the EtherCAT
communication is interrupted, the SM watchdog is triggered after the set time and the outputs are erased.
This setting can be used for adapting a terminal to a slower EtherCAT master or long cycle times. The
default SM watchdog setting is 100 ms. The setting range is 0..65535. Together with a multiplier with a range
of 1..65535 this covers a watchdog period between 0..~170 seconds.
Calculation
Multiplier = 2498 → watchdog base time = 1 / 25MHz * (2498 + 2) = 0.0001seconds = 100µs
SM watchdog = 10000 → 10000 * 100µs = 1second watchdog monitoring time
CAUTION
Undefined state possible!
The function for switching off of the SM watchdog via SM watchdog = 0 is only implemented in terminals from version -0016. In previous versions this operating mode should
not be used.
CAUTION
Damage of devices and undefined state possible!
If the SM watchdog is activated and a value of 0 is entered the watchdog switches off completely. This is the deactivation of the watchdog! Set outputs are NOT set in a safe state, if
the communication is interrupted.
3.4 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.
Loading...