Beckhoff EL3751 Operator's manual

Short documentation | EN
EL3751
1-channel multi-functional input for measurement technology, 24 bit, 10
ksps
2023-06-15 | Version: 3.9

Table of contents
EL3751 3Version: 3.9
Table of contents
1 Foreword....................................................................................................................................................7
1.1 Notes on the documentation .............................................................................................................7
1.2 Safety instructions.............................................................................................................................8
1.3 Documentation Issue Status .............................................................................................................9
1.4 Guide through documentation.........................................................................................................10
1.5 Version identification of EtherCAT devices .....................................................................................11
1.5.1 General notes on marking................................................................................................11
1.5.2 Version identification of EL terminals ............................................................................... 11
1.5.3 Beckhoff Identification Code (BIC) ................................................................................... 12
1.5.4 Electronic access to the BIC (eBIC).................................................................................13
1.5.5 BIC within CoE of EL3751................................................................................................ 16
2 Product overview ....................................................................................................................................17
2.1 Description ......................................................................................................................................17
2.2 Technical data.................................................................................................................................18
2.2.1 Common technical data ................................................................................................... 18
2.2.2 Process data interpretation .............................................................................................. 20
2.2.3 General Information on Measuring Accuracy/Measurement Uncertainty......................... 22
2.2.4 Measurement ±30 V.........................................................................................................26
2.2.5 Measurement ±10 V.........................................................................................................28
2.2.6 Measurement ±5 V...........................................................................................................30
2.2.7 Measurement ±2.5 V........................................................................................................32
2.2.8 Measurement ±1.25 V......................................................................................................34
2.2.9 Measurement ±640 mV....................................................................................................36
2.2.10 Measurement ±320 mV....................................................................................................38
2.2.11 Measurement ±160 mV....................................................................................................40
2.2.12 Measurement ±80 mV......................................................................................................42
2.2.13 Measurement ±40 mV......................................................................................................44
2.2.14 Measurement ±20 mV......................................................................................................46
2.2.15 Measurement ±10 mV......................................................................................................48
2.2.16 Measurement ±5 mV........................................................................................................50
2.2.17 Measurement 0…5 V .......................................................................................................52
2.2.18 Measurement 0…10 V .....................................................................................................54
2.2.19 Measurement ±20 mA......................................................................................................56
2.2.20 Measurement 0…20 mA ..................................................................................................58
2.2.21 Measurement 4…20 mA ..................................................................................................60
2.2.22 Measurement 3.6…21 mA (NAMUR NE43).....................................................................63
2.2.23 Measurement resistance 0…5 kΩ....................................................................................65
2.2.24 RTD measurement...........................................................................................................69
2.2.25 Potentiometer measurement............................................................................................72
2.2.26 Measurement SG 1/1 bridge (full bridge) 4/6-wire connection.........................................74
2.2.27 Measurement SG 1/2 bridge (half bridge) 3/5-wire connection........................................79
2.2.28 Measurement SG 1/4 bridge (quarter bridge) 120Ω 2/3-wire connection ....................... 85
2.2.29 Measurement SG 1/4 bridge (quarter bridge) 350Ω 2/3-wire connection ....................... 89
3 Commissioning .......................................................................................................................................93

Table of contents
EL37514 Version: 3.9
3.1 Notes to short documentation .........................................................................................................93
3.2 CoE overview ..................................................................................................................................94
3.2.1 0x6000 PAI Status Ch.1...................................................................................................94
3.2.2 0x6001 PAI Samples Ch.1 ............................................................................................... 94
3.2.3 0x6002 PAI Synchronous Oversampling Ch.1.................................................................94
3.2.4 0x7000 PAI Control Ch.1 ................................................................................................. 94
3.2.5 0x8000 PAI Settings Ch.1 ................................................................................................ 95
3.2.6 0x8001 PAI Filter 1 Settings Ch.1 .................................................................................... 97
3.2.7 0x8003 PAI Filter 2 Settings Ch.1 .................................................................................... 97
3.2.8 0x8005 Scaler Settings Ch.1............................................................................................ 97
3.2.9 0x800E PAI User Calibration Data Ch.1 .......................................................................... 98
3.2.10 0x800F PAI Vendor Calibration Data Ch.1 ......................................................................98
3.2.11 0x9000 PAI Internal Data Ch.1 ........................................................................................99
3.2.12 0x900F PAI Calibration Dates Ch.1 ...............................................................................101
3.2.13 0xF000 Modular device profile.......................................................................................103
3.2.14 0xF008 Code word.........................................................................................................103
3.2.15 0xF009 Password Protection .........................................................................................103
3.2.16 0xF010 Module list.........................................................................................................103
3.2.17 0xF600 PAI Timestamp..................................................................................................103
3.2.18 0xF900 PAI Info Data.....................................................................................................104
3.2.19 0xF912 filter info.............................................................................................................104
3.2.20 0xFB00 PAI Command ..................................................................................................104
3.3 Sample programs..........................................................................................................................105
3.3.1 Sample program 1 and 2 (offset/gain)............................................................................ 107
3.3.2 Sample program 3 (write LookUp table) ........................................................................ 113
3.3.3 Sample program 4 (generate LookUp table)..................................................................114
3.3.4 Sample program5(write filter coefficients)....................................................................116
3.3.5 Sample program 6 (interlacing of measured values) ..................................................... 118
3.3.6 Sample program 7 (general decimation in the PLC) ...................................................... 123
3.3.7 Sample program 8 (FB for real time diagnosis) ............................................................. 128
3.3.8 Sample program 9 (R/W signature of calibration) .......................................................... 131
4 EL3751 Features....................................................................................................................................133
5 Commissioning on EtherCAT Master..................................................................................................134
5.1 General Commissioning Instructions for an EtherCAT Slave .......................................................134
5.2 TwinCAT Quick Start.....................................................................................................................142
5.2.1 TwinCAT 2 .....................................................................................................................144
5.2.2 TwinCAT 3 .....................................................................................................................154
5.3 TwinCAT Development Environment ............................................................................................167
5.3.1 Installation of the TwinCAT real-time driver ................................................................... 168
5.3.2 Notes regarding ESI device description ......................................................................... 174
5.3.3 TwinCAT ESI Updater....................................................................................................178
5.3.4 Distinction between Online and Offline .......................................................................... 178
5.3.5 OFFLINE configuration creation..................................................................................... 179
5.3.6 ONLINE configuration creation ...................................................................................... 184
5.3.7 EtherCAT subscriber configuration ................................................................................ 192

Table of contents
EL3751 5Version: 3.9
5.3.8 Import/Export of EtherCAT devices with SCI and XTI.................................................... 201
5.4 EtherCAT basics ...........................................................................................................................207
5.5 EtherCAT cabling – wire-bound ....................................................................................................207
5.6 General notes for setting the watchdog ........................................................................................208
5.7 EtherCAT State Machine ..............................................................................................................210
5.8 CoE Interface ................................................................................................................................212
5.9 Distributed Clock ...........................................................................................................................217
6 Mounting and wiring .............................................................................................................................218
6.1 Installation positions......................................................................................................................218
6.2 Positioning of passive Terminals...................................................................................................219
6.3 ATEX - Special conditions (standard temperature range).............................................................221
6.4 Notes regarding connectors and wiring.........................................................................................222
6.5 Shielding concept..........................................................................................................................223
6.6 Installation on mounting rails.........................................................................................................225
6.7 Connection ....................................................................................................................................228
6.7.1 Connection system......................................................................................................... 228
6.7.2 Wiring .............................................................................................................................231
6.7.3 Shielding ........................................................................................................................232
6.8 Note - Power supply......................................................................................................................232
6.9 LED indicators - meanings ............................................................................................................232
6.10 Connection ....................................................................................................................................233
6.11 Disposal ........................................................................................................................................234
7 Appendix................................................................................................................................................235
7.1 Diagnostics - basic principles of diag messages...........................................................................235
7.2 TcEventLogger and IO ..................................................................................................................242
7.3 UL notice .......................................................................................................................................246
7.4 Continuative documentation for ATEX and IECEx........................................................................248
7.5 EtherCAT AL Status Codes ..........................................................................................................248
7.6 Firmware Update EL/ES/EM/ELM/EPxxxx....................................................................................248
7.6.1 Device description ESI file/XML ..................................................................................... 249
7.6.2 Firmware explanation.....................................................................................................252
7.6.3 Updating controller firmware *.efw ................................................................................. 253
7.6.4 FPGA firmware *.rbf ....................................................................................................... 255
7.6.5 Simultaneous updating of several EtherCAT devices .................................................... 259
7.7 Firmware compatibility ..................................................................................................................260
7.8 Firmware compatibility - passive terminals ...................................................................................260
7.9 Restoring the delivery state...........................................................................................................260
7.10 Notes on analog aspects to EL3751/ ELM3xxx ............................................................................261
7.11 Continuative documentation for I/O components with analog in and outputs ...............................262
7.12 Support and Service......................................................................................................................263
7.13 Reshipment and return..................................................................................................................263

Table of contents
EL37516 Version: 3.9

Foreword
EL3751 7Version: 3.9
1 Foreword
NOTICE
Within this short documentation some chapters are only available in a shortened version. For the complete
documentation please contact the Beckhoff sales department responsible for you.
1.1 Notes on the documentation
Intended audience
This description is only intended for the use of trained specialists in control and automation engineering who
are familiar with the applicable national standards.
It is essential that the documentation and the following notes and explanations are followed when installing
and commissioning these components.
It is the duty of the technical personnel to use the documentation published at the respective time of each
installation and commissioning.
The responsible staff must ensure that the application or use of the products described satisfy all the
requirements for safety, including all the relevant laws, regulations, guidelines and standards.
Disclaimer
The documentation has been prepared with care. The products described are, however, constantly under
development.
We reserve the right to revise and change the documentation at any time and without prior announcement.
No claims for the modification of products that have already been supplied may be made on the basis of the
data, diagrams and descriptions in this documentation.
Trademarks
Beckhoff®, TwinCAT®, TwinCAT/BSD®, TC/BSD®, EtherCAT®, EtherCATG®, EtherCATG10®, EtherCATP®,
SafetyoverEtherCAT®, TwinSAFE®, XFC®, XTS® and XPlanar® are registered trademarks of and licensed by
Beckhoff Automation GmbH. Other designations used in this publication may be trademarks whose use by
third parties for their own purposes could violate the rights of the owners.
Patent Pending
The EtherCAT Technology is covered, including but not limited to the following patent applications and
patents: EP1590927, EP1789857, EP1456722, EP2137893, DE102015105702 with corresponding
applications or registrations in various other countries.
EtherCAT® is registered trademark and patented technology, licensed by Beckhoff Automation GmbH,
Germany.
Copyright
© Beckhoff Automation GmbH & Co. KG, Germany.
The reproduction, distribution and utilization of this document as well as the communication of its contents to
others without express authorization are prohibited.
Offenders will be held liable for the payment of damages. All rights reserved in the event of the grant of a
patent, utility model or design.

Foreword
EL37518 Version: 3.9
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.
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
EL3751 9Version: 3.9
1.3 Documentation Issue Status
Version Comment
3.9 • “Guide through documentation“ within foreword added
• Chapter “Product overview” and subchapter “Mounting and wiring”/ “LED indicators – mean-
ings” updated
• Subchapter “Commissioning”/ “CoE overview” updated

Foreword
EL375110 Version: 3.9
1.4 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
I/O Analog Manual (PDF)Notes on I/O components with analog in and outputs
Explosion Protection for Terminal
Systems(PDF)
Notes on the use of the Beckhoff terminal systems in
hazardous areas according to ATEX and IECEx
Infrastructure for EtherCAT/Ethernet (PDF)Technical recommendations and notes for design,
implementation and testing
Software Declarations I/O (PDF)Open source software declarations for
Beckhoff I/O components
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
EL3751 11Version: 3.9
1.5 Version identification of EtherCAT devices
1.5.1 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.
1.5.2 Version identification of EL terminals
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

Foreword
EL375112 Version: 3.9
Fig.1: EL2872 with revision 0022 and serial number 01200815
1.5.3 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:
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

Foreword
EL3751 13Version: 3.9
Posi-
tion
Type of
information
Explanation Data
identifier
Number of digits
incl. data identifier
Example
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.
1.5.4 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.

Foreword
EL375114 Version: 3.9
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
EL3751 15Version: 3.9
◦ 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 etc.
Currently, no electronic storage and readout is planned for these devices.

Foreword
EL375116 Version: 3.9
1.5.5 BIC within CoE of EL3751
Overview of BIC support: CoE object 0x10E2 (BIC) has been included since FW13.
For unique identification, the object 0x10E2 is to be used instead of the 0xF083, which was previously
partially available.

Product overview
EL3751 17Version: 3.9
2 Product overview
Fig.4: EL3751, EL3751-0004, EL3751-0024; LEDs, connections and assignment
1-channel multi-functional input for analog measurement technology, 24 bit, 10 ksps, differential
inputs, oversampling
2.1 Description
This documentation covers the following device descriptions
• EL3751-0000 multifunctional terminal
• EL3751-0020 like EL3751-0000, additionally with Beckhoff factory calibration certificate
• EL3751-0004 reduced to resistance measurement variant of EL3751‑0000 for resistance measurement
up to 5kΩ and RTD-based (temperature) measurement, technical features there like EL3751‑0000
• EL3751-0024 like EL3751‑0004, additionally with Beckhoff factory calibration certificate
As a multi-functional input for analog measurement technology, the EL3751‑0000 analog input terminal can
be used for measuring electrical parameters in several measuring ranges. The respective nominal
measuring ranges are:
• Voltage between ±5 mV and ±30 V, 0..10V, 0..5V
• Current in the range ±20 mA , 4..20mA, 0..20mA, NAMUR NE43
• Resistor bridge, strain gauge (SG): 1/4 bridge (350 Ω + 120 Ω),
1/2 bridge (±16 mV/V) and 1/1 bridge (±32 mV/V) in 2-6 wire connection
• Electrical resistance R / temperature with RTD (PT100 etc.): 0…5 kΩ in 2-4 wire connection
• Potentiometer up to 1kΩ
The nominal measuring range referred to above is part of the total available and usable technical measuring
range, which for the EL3751 is approx. ±107%, depending on the measuring range. The "extended range"
property can be disabled, in order to make the behavior compatible with the EL30/31/36xx "legacy range".

Product overview
EL375118 Version: 3.9
The measurement takes place via a differential input channel. It is digitized with a resolution of 24bit and
10ksps and transported electrically isolated from the fieldbus to the higher-level automation device with
optional oversampling. The integrated supply and the switchable auxiliary resistors enable direct connection
of a resistor bridge (strain gauge SG) or load cell with 2-/3-/4-/6-wire connection technology, a fixed resistor,
a PTC or a potentiometer. The signal state of the EtherCAT Terminal is indicated by light emitting diodes.
If a lower sampling rate is required, a data rate reduction (referred to as decimation) can be set internally,
based on the fixed analog sampling rate of 10ksps. The sampling rate of ≤10ksps achieved in this way can
then be transferred to the controller via EtherCAT, based on the task cycle time and a suitable oversampling
factor.
The terminal has two configurable numeric software filters up to FIR 39th order (40 taps) or IIR 6th order. The
first filter is applied to the 10ksps raw data, the second filter is based on the user-settable decimation, with a
view to suppressing aliasing effects. Both filters can be set based on an integrated list (a number of low-
pass, high-pass, mean value filters) or a freely selectable coefficient table.
Non-linear characteristic sensor curves can be corrected flexibly through an integrated sampling points table.
Simple mathematical operations are also possible.
Each terminal has a unique ID number, which is printed and electronically readable. The optionally available
factory calibration certificate (EL3751-0020, EL3751-0024) can be assigned via this ID number; re-calibration
is possible.
2.2 Technical data
2.2.1 Common technical data
Technical data EL3751
Analog inputs 1 channel
Connection technology 2 - 6 wire
Resolution 24 bit including sign, 32 bit display
Sampling type simultaneous
Ground reference differential
Selection of oversampling factors 1, 2, 4, 5, 8, 10, 16, 20, 25, 32, 40, 50, 64
ADC conversion method deltaSigma ΔΣ, 1.28 msps (internal sampling rate)
Limit frequency input filter hardware Before AD converter: 30 kHz hardware filter
Within ADC after conversion: -3dB @3.2 kHz, mean
value filter 5th order
Measuring error Typically ±0.01% @ 23°C, exceptions for individual
measuring ranges, details see function tables and 2)
below.
Max. sampling rate/conversion time 10ksps/ 100µs (fixed, additionally free
downsampling in firmware through decimation factor)
Supported EtherCAT cycle time
(depending on the operation mode)
DistributedClocks: min.100µs, max.25ms
(max.10ms recommended)
FrameTriggered/Synchron: min.200µs, max.100ms
FreeRun: not supported
Signal delay (step response) tbd.
Signal delay (linear) tbd.
Phase response linear, constant envelope delay
Acquisition method Simultaneous (1 channel, simultaneous with DC
synchronization of several terminals)
Dielectric strength - destruction limit max. permitted short-term/continuous voltage
• Voltage between each contact point ±I1, ±I2, +UV,
and –UV,: non-supplied ±40V, supplied ±36V

Product overview
EL3751 19Version: 3.9
Technical data EL3751
• Voltage between every contact point and SGND
(shield, mounting rail): see information to electrical
isolation
Note: -UV, corresponds to internal GND
Recommended operation voltage range to
compliance with specification (UCM, common mode)
max. permitted voltage during specified normal
operation
• ±I1 and ±I2: typ. ±10V against –UV,
Note: -UV, corresponds to internal GND
Distributed Clocks Yes, with oversampling
Electrical isolation bus/channel 500 V DC (1min. typical test voltage)
Electrical isolation channel/channel (not applicable since 1 channel)
Bit width of the process image (default setting) 32 bit / per value
Supports CoE Interface [}213] function Yes
Special features integrated switchable ¼ bridge extension for 120 and
350 Ω
Higher-order synchronization, PeakHold drag
indicator, predefined and freely configurable software
filters, TrueRMS, freely selectable downsampling, 2-
stage integrator/differentiator, free scaling function
(also non-linear), end value limiter, extended/legacy
range, line compensation
Available with factory calibration certificate on
request
Internal surge voltage protection of the inputs related
to -Uv (internal ground)
+IN1, -IN1: at approx. 12 ±0.5V
(within 30V-Mode at approx. 37 ±1V)
+IN2, -IN2: at approx. <-0.3V or >+5.3V
Supply voltage for electronic via the E-bus
Current consumption via E-bus typ. 260mA
Thermal power dissipation typ. 1.2W
Current consumption from the power contacts none
Permissible operating altitude range 0 to 2000 m (derating at higher altitudes on request)
Weight approx. 65 g
Permissible ambient temperature range during
operation
0…+55 °C (in horizontal installation position)
0…+45°C (all other installation positions)
Permissible ambient temperature range during
storage
-25…+85 °C
Installation position Operation possible in all installation positions;
compliance with full accuracy only possible in
horizontal/standard position.
Permissible relative humidity 95%, no condensation
Max. sensor wire length The wire length from the EtherCAT terminal to the
sensor/encoder must have max. 30 m without any
action of protection. For larger wire lengths a proper
over voltage protection (surge protection) is required.
Dimensions (W x H x D) approx. 15 mm x 100 mm x 70 mm (width aligned: 12
mm)
Mounting on 35 mm mounting rail conforms to EN 60715
Vibration/shock resistance conforms to EN 60068-2-6 / EN 60068-2-27
EMC immunity/emission conforms to EN 61000-6-2 / EN 61000-6-4
Protection class IP20
Approvals/ markings *) CE, UKCA, EAC, UL [}246], ATEX [}221]

Product overview
EL375120 Version: 3.9
*) Real applicable approvals/markings see type plate on the side (product marking).
2) Dominant part of the basic accuracy is its offset specification (see following tables). The process described
in the Offset correction section eliminates this proportion and increases the measurement accuracy
considerably.
Ex marking
Standard Marking
ATEX II 3 G Ex nA IIC T4 Gc
2.2.2 Process data interpretation
The entire measurement range is constituted as follows with regard to the output of the cyclic process data:
Fig.5: Basic range of a process data value
The channel for this terminal features an option to set the measuring range either to the conventional
Beckhoff type, up until now: "nominal full-scale value = PDO end value: LegacyRange" or the new method
"technical full-scale value = PDO end value: ExtendedRange".
• For Extended Range mode, the following applies:
◦ technical full scale value = PDO end value 0x007FFFFF.
◦ for information purposes, the channel can measure up to approx. 107% beyond the nominal range,
although accuracy specifications etc. are then no longer valid.
◦ outside the nominal measuring range, the Overrange or Underrange bit is set.
◦ for further diagnosis, the error bit and the error LED are set if configurable limits are exceeded or
not reached. By default, the limits are set to the technical measuring range, although they can be
narrowed by the customer.
Example: In the 4…20 mA measuring range, the lower limit is set to 0mA, although it can be
customized in the CoE by the customer, e.g. set to 3.6mA, in order to enable earlier detection of
potential sensor faults.
◦ The Extended Range mode is the default setting for the terminal ex works.
◦ The mode is defined through the non-periodic rational LSB step size and an integer end value.
This enables the step size to be used in a PLC program without a rounding error.
• For Legacy Range mode, the following applies: