Beckhoff EL3681 Operator's manual

Documentation | EN
EL3681
Digital Multimeter Terminal
2023-12-14 | Version: 3.0

Table of contents
EL3681 3Version: 3.0
Table of contents
1 Foreword....................................................................................................................................................7
1.1 Notes on the documentation .............................................................................................................7
1.2 Guide through documentation...........................................................................................................8
1.3 Safety instructions.............................................................................................................................9
1.4 Documentation issue status ............................................................................................................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 ............................................................................... 12
1.5.3 Beckhoff Identification Code (BIC) ................................................................................... 13
1.5.4 Electronic access to the BIC (eBIC).................................................................................15
2 Product description ................................................................................................................................17
2.1 Introduction .....................................................................................................................................17
2.2 Technical data.................................................................................................................................19
2.3 Technology......................................................................................................................................20
2.4 Note on Beckhoff calibration certificates .........................................................................................23
2.5 Start.................................................................................................................................................25
3 Basics communication ...........................................................................................................................26
3.1 EtherCAT basics .............................................................................................................................26
3.2 EtherCAT cabling – wire-bound ......................................................................................................26
3.3 General notes for setting the watchdog ..........................................................................................27
3.4 EtherCAT State Machine ................................................................................................................29
3.5 CoE Interface ..................................................................................................................................31
3.6 Distributed Clock .............................................................................................................................36
4 Mounting and wiring ...............................................................................................................................37
4.1 Instructions for ESD protection .......................................................................................................37
4.2 Installation on mounting rails...........................................................................................................38
4.3 Connection ......................................................................................................................................41
4.3.1 Connection system........................................................................................................... 41
4.3.2 Wiring ...............................................................................................................................43
4.3.3 Shielding ..........................................................................................................................44
4.4 Positioning of passive Terminals.....................................................................................................45
4.5 Installation positions........................................................................................................................46
4.6 LEDs and connection ......................................................................................................................48
4.7 Disposal ..........................................................................................................................................49
5 Commissioning .......................................................................................................................................50
5.1 TwinCAT Quick Start.......................................................................................................................50
5.1.1 TwinCAT 2 .......................................................................................................................53
5.1.2 TwinCAT 3 .......................................................................................................................63
5.2 TwinCAT Development Environment ..............................................................................................77
5.2.1 Installation of the TwinCAT real-time driver ..................................................................... 77
5.2.2 Notes regarding ESI device description ........................................................................... 83
5.2.3 TwinCAT ESI Updater......................................................................................................87
5.2.4 Distinction between Online and Offline ............................................................................ 87

Table of contents
EL36814 Version: 3.0
5.2.5 OFFLINE configuration creation....................................................................................... 88
5.2.6 ONLINE configuration creation ........................................................................................ 93
5.2.7 EtherCAT subscriber configuration ................................................................................ 101
5.2.8 Import/Export of EtherCAT devices with SCI and XTI.................................................... 110
5.3 General Commissioning Instructions for an EtherCAT Slave .......................................................117
5.4 Notices on analog specifications...................................................................................................125
5.4.1 Full scale value (FSV), output end value ....................................................................... 125
5.4.2 Measurement error/measurement deviation/measurement uncertainty, output uncertainty
.......................................................................................................................................126
5.4.3 Temperature coefficient tK [ppm/K]................................................................................ 127
5.4.4 Long-term use ................................................................................................................ 128
5.4.5 Ground reference: single-ended/differential typification.................................................129
5.4.6 Common-mode voltage and reference ground (based on differential inputs) ................ 134
5.4.7 Dielectric strength .......................................................................................................... 135
5.4.8 Temporal aspects of analog/digital or digital/analog conversion.................................... 136
5.4.9 Explanation of the term GND/Ground ............................................................................ 139
5.4.10 Sampling type: Simultaneous vs. multiplexed................................................................141
5.5 Basic function principles/functional description.............................................................................144
5.5.1 Measuring ranges and output ........................................................................................ 144
5.5.2 Selecting a measuring range ........................................................................................ 144
5.5.3 Autorange....................................................................................................................... 145
5.5.4 Filter ...............................................................................................................................145
5.5.5 Frequency ......................................................................................................................145
5.5.6 Presentation ...................................................................................................................146
5.5.7 Zero Compensation Interval...........................................................................................146
5.5.8 Calibration ......................................................................................................................146
5.6 Process data .................................................................................................................................147
5.6.1 Process image ............................................................................................................... 147
5.6.2 Control, Status, Settings-Word....................................................................................... 149
5.6.3 PDO Assignment............................................................................................................ 150
5.6.4 Calculation of process data............................................................................................151
5.6.5 Determining (user) gain values ...................................................................................... 153
5.7 Object description and parameterization.......................................................................................154
5.7.1 Restore object ................................................................................................................ 155
5.7.2 Configuration data..........................................................................................................155
5.7.3 Configuration data (vendor-specific) .............................................................................. 157
5.7.4 Input data ....................................................................................................................... 158
5.7.5 Output data .................................................................................................................... 159
5.7.6 Information and diagnostic data ..................................................................................... 159
5.7.7 Standard objects (0x1000-0x1FFF) ............................................................................... 159
5.8 Sample Program ...........................................................................................................................164
6 Error handling and diagnostics ...........................................................................................................168
7 Appendix................................................................................................................................................169
7.1 Accessories...................................................................................................................................169
7.2 EtherCAT AL Status Codes ..........................................................................................................170
7.3 Firmware compatibility ..................................................................................................................171

Table of contents
EL3681 5Version: 3.0
7.4 Firmware Update EL/ES/EM/ELM/EP/EPP/ERPxxxx ...................................................................172
7.4.1 Device description ESI file/XML ..................................................................................... 173
7.4.2 Firmware explanation.....................................................................................................176
7.4.3 Updating controller firmware *.efw ................................................................................. 177
7.4.4 FPGA firmware *.rbf ....................................................................................................... 179
7.4.5 Simultaneous updating of several EtherCAT devices .................................................... 183
7.5 Restoring the delivery state...........................................................................................................184
7.6 Support and Service......................................................................................................................186

Table of contents
EL36816 Version: 3.0

Foreword
EL3681 7Version: 3.0
1 Foreword
1.1 Notes on the documentation
Intended audience
This description is only intended for the use of trained specialists in control and automation engineering who
are familiar with the applicable national standards.
It is essential that the documentation and the following notes and explanations are followed when installing
and commissioning these components.
The qualified personnel is obliged to always use the currently valid documentation.
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
EL36818 Version: 3.0
1.2 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
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
EL3681 9Version: 3.0
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.
Signal words
The signal words used in the documentation are classified below. In order to prevent injury and damage to
persons and property, read and follow the safety and warning notices.
Personal injury warnings
DANGER
Hazard with high risk of death or serious injury.
WARNING
Hazard with medium risk of death or serious injury.
CAUTION
There is a low-risk hazard that could result in medium or minor injury.
Warning of damage to property or environment
NOTICE
The environment, equipment, or data may be damaged.
Information on handling the product
This information includes, for example:
recommendations for action, assistance or further information on the product.

Foreword
EL368110 Version: 3.0
1.4 Documentation issue status
Version Comment
2.9 • Update chapter "Technical data"
• Update structure
2.8 • Update chapter "Technical data"
• Chapter “Disposal” added
• Update structure
2.7 • Update chapter "Technical data"
• Update structure
2.6 • Addenda EL3681-0020 and EL3681-0030
• Update chapter "Technical data"
• Update structure
• Update revision status
2.5 • Update chapter "UL notes"
• Update structure
2.4 • Update chapter "Technical data"
• Update structure
• Update revision status
2.3 • Update chapter "Sample Program"
• Update structure
• Update revision status
2.2 • Addenda chapter "Instructions for ESD protection"
• Addenda chapter "Notices on Analog specification"
2.1 • Update chapter "Notes on the documentation"
• Correction of Technical data
• Update chapter "TwinCAT 2.1x" -> "TwinCAT Development Environment" and
"TwinCAT Quick Start"
• Update revision status
2.0 • Migration
• Update structure
1.6 • Update structure
• Update chapter "Technical data"
1.5 • Update chapter "Basic function principles"
1.4 • Update firmware status
• Update chapter "Technology"
1.3 • Update firmware status
• Update application note
1.2 • Update TrueRMS, Crest factor
1.1 • Update LED description
1.0 • First public issue
0.2 • Corrections and addenda
0.1 • Preliminary documentation for EL3681

Foreword
EL3681 11Version: 3.0
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.

Foreword
EL368112 Version: 3.0
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
Fig.1: EL2872 with revision 0022 and serial number 01200815

Foreword
EL3681 13Version: 3.0
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:

Foreword
EL368114 Version: 3.0
Posi-
tion
Type of
information
Explanation Data
identifier
Number of digits
incl. data identifier
Example
1 Beckhoff order
number
Beckhoff order number 1P 8 1P072222
2 Beckhoff Traceability
Number (BTN)
Unique serial number,
see note below
SBTN 12 SBTNk4p562d7
3 Article description Beckhoff article
description, e.g.
EL1008
1K 32 1KEL1809
4 Quantity Quantity in packaging
unit, e.g. 1, 10, etc.
Q 6 Q1
5 Batch number Optional: Year and week
of production
2P 14 2P401503180016
6 ID/serial number Optional: Present-day
serial number system,
e.g. with safety products
51S 12 51S678294
7 Variant number Optional: Product variant
number on the basis of
standard products
30P 32 30PF971, 2*K183
...
Further types of information and data identifiers are used by Beckhoff and serve internal processes.
Structure of the BIC
Example of composite information from positions 1 to 4 and with the above given example value on position
6. The data identifiers are highlighted in bold font:
1P072222SBTNk4p562d71KEL1809 Q1 51S678294
Accordingly as DMC:
Fig.3: Example DMC 1P072222SBTNk4p562d71KEL1809 Q1 51S678294
BTN
An important component of the BIC is the Beckhoff Traceability Number (BTN, position 2). The BTN is a
unique serial number consisting of eight characters that will replace all other serial number systems at
Beckhoff in the long term (e.g. batch designations on IO components, previous serial number range for
safety products, etc.). The BTN will also be introduced step by step, so it may happen that the BTN is not yet
coded in the BIC.
NOTICE
This information has been carefully prepared. However, the procedure described is constantly being further
developed. We reserve the right to revise and change procedures and documentation at any time and
without prior notice. No claims for changes can be made from the information, illustrations and descriptions
in this information.

Foreword
EL3681 15Version: 3.0
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.
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".
◦ Access from the PLC: From TwinCAT 3.1. build 4024.24 the functions FB_EcReadBIC and
FB_EcReadBTN are available in the Tc2_EtherCAT Library from v3.3.19.0 for reading into the
PLC..
• 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
EL368116 Version: 3.0
◦ 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 are
available in the Tc2_EtherCAT Library from v3.3.19.0 for reading into the PLC.
• For processing the BIC/BTN data in the PLC, the following auxiliary functions are available in
Tc2_Utilities from TwinCAT 3.1 build 4024.24 onwards
◦ F_SplitBIC: The function splits the Beckhoff Identification Code (BIC) sBICValue into its
components based on known identifiers and returns the recognized partial strings in a structure
ST_SplitBIC as return value.
◦ BIC_TO_BTN: The function extracts the BTN from the BIC and returns it as a value.
• 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.

Product description
EL3681 17Version: 3.0
2 Product description
2.1 Introduction
Fig.4: EL3681
Digital multimeter terminal
The EL3681 EtherCAT Terminal enables measurement of currents and voltages in wide input range. The
measuring ranges are switched automatically, as usual in advanced digital multimeters. There are two
current paths available for current measurement. One of them is a high current path for up to 10 A.
The current and the voltage measurement facility can be used for DC and AC. The alternating parameters
are output as true RMS values. The input signal can cover a range up to 1 kHz, without affecting the
measuring accuracy. A non-sinus signal form is allowed, if the Crest factor is < 3.
The measurement readings can be read and processed with EtherCAT. At the same time, the EL3681
enables the measuring type and range to be set via the bus.
Excellent interference immunity is achieved through the fully electrically isolated design of the electronic
measuring system and the dual slope conversion system. High precision and simple, high impedance
measurement from 300 mV to 300 V allow the EtherCAT terminals to be used like a modern digital
multimeter. The sample rate lies between approx. 500 ms if the filter is activated and approx. 62 ms if the
filter is deactivated.
The selected measuring type and overload are indicated by LEDs.
In measuring applications in particular, the voltage to be expected is often not yet known during the planning
phase. Automatic adjustment of the measurement range simplifies use and reduces stock levels.
As high-precision variants, the EL3681-0020 with individual factory calibration certificate and the EL3681-0030
with external calibration certificate are available.
Please read the notes on the calibration certificate [}23] and identification features [}23] of these
terminals.

Product description
EL368118 Version: 3.0
Quick links
• EtherCAT basics
• Basic function principles EL3681 [}144]
• Process data [}147]
• CoE object description and parameterization [}154]
• Sample programs [}164]
• Error handling [}168]
• Accessories [}169]

Product description
EL3681 19Version: 3.0
2.2 Technical data
Technical data EL3681 EL3681-0020 EL3681-0030
Number of inputs 1, voltage or current (1A/ 10A)
Technology digital multimeter with automatic range selection
Measured values Current AC/DC, Voltage AC/DC **)
Measuring ranges voltage 300mV, 3V, 30V, 300V
Dielectric strength - Destruction limit 480VACRMS/DC
Measuring ranges current 100mA, 1A and 10A via high-current path
Current resistance - destruction limit Measuring range 1A: given by fuse;
Measuring range 10A: short-time withstand current 30A for 1sec (min.
5min. cooling time)
Measuring procedure AC with TrueRMS value generation, 0..1kHz input signal, crest factor < 3
permitted
Resolution 18bit + sign in each measurement range
Sampling type simultaneous
Ground reference differential
Internal resistance Measuring range DC300mV – 300V: 12.5MΩ
Measuring range DC100mA – 1A: 0.2Ω
Measuring range DC10A: 3mΩ
Measuring range AC300mV - 300V: 1MΩ, approx. 33pF
Measuring range AC100mA – 1A: 0.2 Ω
Measuring range AC10A: 3mΩ
Measuring error see table [}21] in chapter “Accuracy”
Update time 0.5s, 1s for measuring range selection
Electrical isolation 1,500V (connection terminal/E-bus)
Supply voltage for electronic via the E-bus
Current consumption via E-bus typ. 150mA
Configuration via TwinCAT System Manager
Weight approx. 70g
Permissible ambient temperature range during
operation
-25°C ... +60°C
(extended temperature
range)
0°C ... +55°C
Permissible ambient temperature range during storage -40°C ... +85°C -25°C ... +85°C
Permissible relative humidity 95%, no condensation
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
EMC immunity/emission conforms to EN61000-6-2 / EN61000-6-4
Protection class IP20
Installation position variable
Calibration certificate - with factory calibration
certificate [}23]
with external calibration
certificate [}23]
Marking *) CE, EAC, UKCA
*) Real applicable approvals/markings see type plate on the side (product marking).
*) In AC mode, the terminal operates in TrueRMS mode, i.e. it does not digitally record the peak values Vpp,
which are approx. 1.4 times larger, but the RMS value, see "Measuring procedure [}21]" and chapter
"Technology [}20]".

Product description
EL368120 Version: 3.0
2.3 Technology
Table of contents
General description
Specifications
- Accuracy
- Internal resistances - Fuse
Default setting
General description
The functionality of the EL3681 is similar to that of a commercial digital multimeter. The terminal offers the
following features:
• Single-channel measurement
• AC/DC voltage measurement, range selection automatic through Autorange function or through the
controller; measuring ranges 300mV, 3V, 30V, 300V
• AC/DC current measurement in the 1A path (internal fuse: 1.25A) or 10A path (no internal fuse),
measuring ranges: 100mA, 1A, 10A
• Formation of measured values:
AC current/voltage is calculated as a true RMS value without DC component, an integration of the
signal waveform in the ADC takes place
DC current/voltage is calculated as an arithmetic mean value, an integration of the signal waveform in
the ADC takes place
• Electrical isolation from the fieldbus
• Very good interference immunity through dual-slope conversion technique
• Display of measurement type (current/voltage) and overload through LED
• Typical update rate approx. 2/s, after measuring range change up to approx. 1/s, with deactivated filter
approx. 16/s.
The data collection is shown in fig. Data flow EL3681.
Fig.5: Data flow EL3681
Application note
For the measurement of a 60Hz signal, the CoE(0x8000:0A [}155])object should be set accordingly. For all
other signal frequencies the 50Hz preset is valid, because of the longer integration time. The accuracy
information shown below refer to a input signal of a frequency range of >0 .. 1kHz. With higher frequencies
the measurement accuracy decreases (-3dB>500kHz).
It is possible to measure a non-sinus AC input signal, if the Crest factor is < 3. The accuracy information
below refers to a Crest factor of max. 2.
The simultaneous electrical connection of both current paths (10, 1A) and the voltage path for a following
alternating measurement of values is possible, but not recommended. In case of AC components in the
signal, a parasitic crosstalk from path to path can occur. After switching over, the process data update time
can be up to 1 second.