Beckhoff ELX3351 Operating Manual
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Beckhoff ELX3351 Operating Manual

Beckhoff ELX3351 Operating Manual

1-channel analog input terminal for strain gauge, 16 bit, ex i
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Operating manual
ELX3351
1-channel analog input terminal for strain gauge, 16 bit, Ex i
Version:
Date:
1.3.1
2019-01-15

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Summary of Contents for Beckhoff ELX3351

  • Page 1 Operating manual ELX3351 1-channel analog input terminal for strain gauge, 16 bit, Ex i Version: 1.3.1 Date: 2019-01-15...

  • Page 3: Table Of Contents

    Safety instructions ..........................  6 Documentation Issue Status...................... 7 Marking of ELX terminals........................  8 2 Product overview............................. 11 ELX3351 - Introduction .........................  11 Technical data .......................... 12 Intended use .......................... 13 3 Mounting and wiring .......................... 14 Special conditions of use for ELX terminals .................  14 Installation notes for ELX terminals ....................
  • Page 4 5.5.1 Selection of process data.................... 54 5.5.2 Default process image ..................... 55 5.5.3 Variants Predefined PDO.................... 57 5.5.4 Sync Manager ........................ 58 ELX3351 - Object description and parameterization .............. 59 5.6.1 Restore object ........................ 59 5.6.2 Configuration data...................... 60 5.6.3 Command object ...................... 61 5.6.4 Input data ......................... 61 5.6.5...

  • Page 5: Foreword

    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. Copyright © Beckhoff Automation GmbH & Co. KG, Germany.

  • Page 6: Safety Instructions

    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.

  • Page 7: Documentation Issue Status

    • Chapter Configuration of ELX terminals in Bus Terminal block updated 1.0.1 • Layout updated • Technical data updated • Chapter Mounting and wiring updated • Technical data updated • Chapter Mounting and wiring updated • First preliminary version (for internal use only) ELX3351 Version: 1.3.1...

  • Page 8: Marking Of Elx Terminals

    • Beckhoff Traceability Number, or BTN for short (as a serial number it clearly identifies each terminal) Date code The date code is an eight-digit number given by Beckhoff and printed on the ELX terminal. The date code indicates the build version in the delivery state and thus identifies an entire production batch, but does not distinguish between the terminals in a batch.

  • Page 9: Fig. 1 Elx1052-0000 With Date Code 32180000, Btn 10000100 And Ex Marking

    01 - firmware version 01 00 - hardware version 00 Beckhoff Traceability Number (BTN) In addition, each ELX terminal has a unique Beckhoff Traceability Number (BTN). Ex marking The Ex marking can be found at the top left on the terminal:...

  • Page 10: Fig. 2 Elx9012 With Date Code 32180005 And Ex Marking

    Foreword Fig. 2: ELX9012 with date code 32180005 and Ex marking Version: 1.3.1 ELX3351...

  • Page 11: Product Overview

    Fig. 3: 1-channel analog input terminal for strain gauge, 16 bit, Ex i The analog ELX3351 input terminal enables direct connection of a resistor bridge or load cell from hazardous areas, Zone 0/20 and 1/21. The terminal can be connected in 4- or 6-wire technology. The ratio...

  • Page 12: Technical Data

    Product overview Technical data Technical data ELX3351-0000 Sensor types resistor bridge, strain gauge Number of inputs 1, for 1 resistor bridge in full bridge technology Connection method 4-wire, 6-wire Bridge input resistance 300 Ω…1.5 kΩ Measuring range U max. -18…+18 mV Measuring range U max.

  • Page 13: Intended Use

    IECEx scheme! CAUTION The ELX terminals extend the field of application of the Beckhoff bus terminal system with functions for integrating intrinsically safe field devices from hazardous areas. The intended field of application is data acquisition and control tasks in discrete and process engineering automation, taking into account explosion protection requirements.

  • Page 14: Mounting And Wiring

    • Observe the permissible ambient temperature range of -25 to +60°C of Beckhoff ELX terminals! • Measures must be taken to protect against the rated operating voltage being exceeded by more than 40% due to short-term interference voltages! The power supply of the ELX9560 power supply terminal must correspond to overvoltage category II according...
  • Page 15 1 to 8 on the left above the respective terminal point as well as via the laser image. Observe any possible polarity dependency of connected intrinsically safe circuits! ELX3351 Version: 1.3.1...

  • Page 16: Arrangement Of Elx Terminals Within A Bus Terminal Block

    • The last terminal of each ELX segment is to be covered by an ELX9012 bus end cover, unless two ELX9410 power supply terminals are installed in direct succession for con- tinuing the same terminal segment with standard Beckhoff EtherCAT terminals (e.g. EL/ ES/EK)! Examples for the arrangement of ELX terminals Fig. 4: Valid arrangement of the ELX terminals (right terminal block).

  • Page 17: Fig. 7 Valid Arrangement - Elx9410 In Front Of An Elx9560 Power Supply Terminal

    Fig. 8: Invalid arrangement - missing ELX9560 power supply terminal. Fig. 9: Invalid arrangement - terminal that does not belong to the ELX series within the ELX terminal segment. Fig. 10: Invalid arrangement - second ELX9560 power supply terminal within the ELX terminal segment without an upstream ELX9410. ELX3351 Version: 1.3.1...

  • Page 18: Fig. 11 Invalid Arrangement - Missing Elx9012 Bus End Cover

    ELX9560 power supply terminal in accordance with the specified technical Attention data. If required, an additional power supply terminal ELX9560 with an upstream ELX9410 con- nected (see mounting examples) must be installed or a completely new terminal block must be assembled. Version: 1.3.1 ELX3351...

  • Page 19: Installation Position And Minimum Distances

    • besides the bus terminal block: 20 mm (recommended) Fig. 12: Installation position and minimum distances Observe the minimum separation distances according to IEC 60079-14! Observe the prescribed minimum separation distances between intrinsically safe and non- intrinsically safe circuits according to IEC 60079-14. WARNING ELX3351 Version: 1.3.1...

  • Page 20: Installation Of Elx Terminals On Mounting Rails

    Note flict with the fixing bolts of the mounting rail. To mount the mounting rails with a height of 7.5 mm under the terminals and couplers, you should use flat mounting connections (e.g. countersunk screws or blind rivets). Version: 1.3.1 ELX3351...

  • Page 21: Connection

    Bus Terminals) do not or not fully loop through the power contacts. Connection 3.6.1 Connection system Risk of electric shock and damage of device! Bring the bus terminal system into a safe, powered down state before starting installation, disassembly or wiring of the bus terminals! WARNING ELX3351 Version: 1.3.1...

  • Page 22: Wiring

    Risk of electric shock and damage of device! Bring the bus terminal system into a safe, powered down state before starting installation, disassembly or wiring of the Bus Terminals! WARNING Terminals for standard wiring ELXxxxx Fig. 16: Connecting a cable on a terminal point Version: 1.3.1 ELX3351...

  • Page 23: Proper Line Connection

    In any case, make sure that the galvanic isolation made by the ELX9560 between the 24 V Ex busbar (power contacts +24 V Ex and 0 V Ex) and other system potentials (if applicable WARNING also functional or protective earths) is not removed. ELX3351 Version: 1.3.1...

  • Page 24: Elx3351 - Contact Assignment

    Mounting and wiring 3.6.5 ELX3351 - Contact assignment Fig. 17: ELX3351 - Contact assignment Terminal point Description Name not implemented + input measuring voltage (difference voltage of bridge) + input reference voltage (supply voltage at bridge) + output supply voltage for bridge...

  • Page 25: Fig. 18 Elx3351 - Connection Of A Full Bridge In 6-Wire Technology

    Wiring the bridge Fig. 18: ELX3351 - Connection of a full bridge in 6-wire technology The ELX3351 is standardly designed for a sensor connection in 6-wire technology. In the event that a sensor is to be operated in 4-wire technology, the contacts +U...

  • Page 26: Basic Function Principles

    EtherCAT basics Please refer to the EtherCAT System Documentation for the EtherCAT fieldbus basics, also available as PDF file from www.beckhoff.com. Basic principles of strain gauge technology Basic information on the technological field of strain gauges/load cells as metrological instruments is to be given below.

  • Page 27: Fig. 20 Quarter, Half, And Full Bridge

    In principle a full bridge can be operated with a 4-conductor connection (2 conductors for the supply U and 2 for the measurement of the bridge voltage U ELX3351 Version: 1.3.1...

  • Page 28: Fig. 21 4-Wire Connection

    U with two currentless return conductors in each case. The conductor-related errors are hence omitted. Since these are very small voltage levels of the order of mV and µV, all conductors should be screened. Version: 1.3.1 ELX3351...

  • Page 29: Fig. 23 Example Of A Load Cell

    This indicates the smallest mass that can be measured without the maximum permissible error of the load cell being exceeded [RevT]. This value is represented either by the equation V  / n (where n is an integer, e.g. 10000), or in % of (e.g. 0.01). ELX3351 Version: 1.3.1...
  • Page 30 4000 * 1 g = 4 kg . There are further important characteristic values, which are for the most part self-explanatory and need not be discussed further here, such as nominal characteristic value tolerance, input/output resistance, recommended supply voltage, nominal temperature range etc. Version: 1.3.1 ELX3351...

  • Page 31: Fig. 24 Parallel Strain Gauge

    The mechanically parallel-connected load cells are usually also electrically connected in parallel and to one measuring transducer, e.g. the ELX3351. To this end the following must be observed: • The load cells must be matched to each other and approved by the manufacturer for this mode of operation.
  • Page 32 • OIML (ORGANISATION INTERNATIONALE DE MÉTROLOGIE LÉGALE) www.oiml.org • PTB - Physikalisch-Technischen Bundesanstalt www.ptb.de • www.eichamt.de • WELMEC - European cooperation in legal metrology www.welmec.org • DKD - Deutscher Kalibrierdienst www.dkd.eu • Fachgemeinschaft Waagen (AWA) im Verband Deutscher Maschinen- und Anlagenbau VDMA www.vdma.org Version: 1.3.1 ELX3351...

  • Page 33: Parameterization And Programming

    • Since the two voltages are measured at the same time, there is basically no need for a high-precision reference voltage with respect to the level. The bridge supply and reference voltages are provided by the ELX3351 for the full bridge. A connection of other, externally supplied circuits (e.g. an external bridge supply) is not permitted! •...

  • Page 34: Fig. 26 Parallel Connection With Elx3351

    Parameterization and programming • Parallel operation of load cells is possible with the ELX3351. Please note: ◦ Load cells approved and calibrated by the load cell manufacturer for parallel operation should be used. The nominal characteristic values [mV/V], zero offset [mV/V] and impedance [Ω, ohm] are then usually adjusted accordingly.

  • Page 35: Block Diagram

    5.1.3 Software filter The ELX3351 is equipped with a digital software filter which, depending on its settings, can adopt the characteristics of a Finite Impulse Response filter (FIR filter), or an Infinite Impulse Response filter (IIR filter). The filter is activated by default as 50Hz-FIR.

  • Page 36: Fig. 29 Step Response Of The Iir Filter

    (see table) The IIR filter works cycle-synchronously. Note Hence, a new measured value is available in each PLC cycle. IIR filter Differential equation: Y with a Note = (see table) b1 = 1 - a Version: 1.3.1 ELX3351...

  • Page 37: Dynamic Filter

    If the change in the weight is less than 0.5 digit per 100 ms, the filter is set one level stronger every 100 ms until IIR8 is reached. The green line is intended to clarify the decreasing "noise level" ELX3351 Version: 1.3.1...

  • Page 38: Calculating The Weight

    5.2.1 Wiring fail indication The ELX3351 has no express open-circuit recognition facility. If one of the bridge wires is broken, however, the voltage measured there generally moves towards the final value, thus displaying an error in the status word. Over/underrange of the supply voltage is likewise indicated.

  • Page 39: Gravity Adaptation

    • bInputFreeze is set to TRUE for 50 ms by a TOF block on the ELX3351 The effect can be seen in (D): The peak load is no longer acknowledged by the ELX3351. If it is optimally adapted to the expected force impulse, the ELX3351 can measure the current load value without overshoot.

  • Page 40: Idling Recognition

    The evaluation of the measured value and the decision over the degree of calmness can be done in the controller; however, the ELX3351 also offers this function, which is activated by default. The result is output in the status word.

  • Page 41: Sensor Calibration

    5.3.1 Sensor calibration The ELX3351 is matched to the characteristic curve of the sensor element by means of the calibration. Two values are required for this procedure: the initial value without a load (zero balance) and fully loaded (rated output). These values can be determined by a calibration protocol or by a calibration using calibration weights.

  • Page 42: Fig. 34 Zero Calibration With Command 0X0101 In Coe Object 0Xfb00:01

    As soon as the measured value indicates a constant value for at least 10 seconds, execute the com- mand "0x0102" (258 ) on CoE object 0xFB00:01. By means of this command the ELX3351 determines the output value for the nominal weight ("Rated output") Check: CoE objects FB00:02 and FB00:03 must contain "0" after execution Fig. 35: Loading with reference load, command 0x0102 in CoE object 0xFB00:01...

  • Page 43: Self-Calibration

    After a change in the CoE settings (section x80nn), a self-calibration is always performed (even if DisabledCalibration = TRUE), since the settings affect the measurement. Changing the CoE settings during an ongoing measurement should therefore be avoided, if possible. ELX3351 Version: 1.3.1...

  • Page 44: Taring

    The ELX3351 supports 2 tarings; it is recommended to set a strong filter when taring. • Temporary tare The correction value is NOT stored in the terminal and is lost in the event of a power failure.

  • Page 45: Notices On Analog Specifications

    For analog I/O devices from Beckhoff the rule is that the limit with the largest value is chosen as the full scale value of the respective product (also called the reference value) and is given a positive sign. This applies to both symmetrical and asymmetrical measuring spans.

  • Page 46: Temperature Coefficient Tk [Ppm/K]

    A manufacturer can alleviate this by using components of a higher quality or by software means. The temperature coefficient, when indicated, specified by Beckhoff allows the user to calculate the expected measuring error outside the basic accuracy at 23 °C.

  • Page 47: Single-Ended/Differential Typification

    • The term "electrical isolation" should be clarified in advance. Beckhoff IO modules feature 1..8 or more analog channels; with regard to the channel connection a distinction is made in terms of: ◦ how the channels WITHIN a module relate to each other, or ◦...
  • Page 48 The property of electrical isolation indicates whether the channels are directly connected to each other. ◦ Beckhoff terminals/ boxes (and related product groups) always feature electrical isolation between the field/analog side and the bus/EtherCAT side. In other words, if two analog terminals/ boxes are not connected via the power contacts (cable), the modules are effectively electrically isolated.

  • Page 49: Fig. 39 2-Wire Connection

    ‘variable load’. Refer also to the sensor manufacturer’s information. Fig. 39: 2-wire connection Therefore, they are to be connected according to the Beckhoff terminology as follows: preferably to ‘single-ended’ inputs if the +Supply connections of the terminal/ box are also to be used - connect to +Supply and Signal they can, however, also be connected to ‘differential’...

  • Page 50: Common-Mode Voltage And Reference Ground (Based On Differential Inputs)

    Reference ground samples for Beckhoff IO devices: 1. Internal AGND fed out: EL3102/EL3112, resistive connection between the channels 2. 0V power contact: EL3104/EL3114, resistive connection between the channels and AGND; AGND connected to 0V power contact with low-resistance 3.

  • Page 51: Temporal Aspects Of Analog/Digital Conversion

    The conversion of the constant electrical input signal to a value-discrete digital and machine-readable form takes place in the analog Beckhoff EL/KL/EP input modules with ADC (analog digital converter). Although different ADC technologies are in use, from a user perspective they all have a common characteristic: after the conversion a certain digital value is available in the controller for further processing.
  • Page 52 This is the “external” view of the “Beckhoff AI channel” system – internally the signal delay in particular is composed of different components: hardware, amplifier, conversion itself, data transport and processing.
  • Page 53 Fig. 44: Diagram signal delay (linear) 3. Additional information: may be provided in the specification, e.g. 3.1 Actual sampling rate of the ADC (if different from the channel sampling rate) 3.2 Time correction values for run times with different filter settings … ELX3351 Version: 1.3.1...

  • Page 54: Process Data

    Selection of process data The process data of the ELX3351 are set up in the TwinCAT System Manager. The PDOs can be activated or deactivated separately. The ‘Process data’ tab is used for this (visible only if the terminal is selected on the left).

  • Page 55: Default Process Image

    In order to simplify the configuration, typical configuration combinations of process data are stored in the device description. The predefined configurations can be selected in the process data overview. Therefore the function is available only if the ESI/XML files are saved in the system (downloadable from the Beckhoff website).
  • Page 56 The format matches the REAL format of IEC 61131-3, which in turn is based on the REAL format of IEC 559. A REAL number (single precision) is defined as follows (See also Beckhoff InfoSys: TwinCAT PLC Control: standard data types).

  • Page 57: Variants Predefined Pdo

    The format matches the REAL format of IEC 61131-3, which in turn is based on the REAL format of IEC 559. A REAL number (single precision) is defined as follows (See also Beckhoff InfoSys: TwinCAT PLC Control: standard data types). According to IEC61131, this 32-bit variable can be linked directly with a FLOAT variable of the PLC, see "Bit –...

  • Page 58: Sync Manager

    Size Name PDO content cluded PDOs (byte.bit) 0x1600 RMB Control Index 0x7000:01 [} 61] - Start calibration (default) (Resistor Measurement Index 0x7000:02 [} 61] - Disable calibration bridge) Index 0x7000:03 [} 61] - Input freeze Index 0x7000:05 [} 61] - Tare Version: 1.3.1 ELX3351...

  • Page 59: Elx3351 - Object Description And Parameterization

    EtherCAT XML Device Description The display matches that of the CoE objects from the EtherCAT XML Device Description. We recommend downloading the latest XML file from the download area of the Beckhoff Note website and installing it according to installation instructions.

  • Page 60: Configuration Data

    Calibration interval for automatic calibration of the UINT16 0x0708 (1800 terminal. The unit is 100 ms. The smallest possible value is 5 (500 ms). A value of 0 deactivates automatic self-calibration. This is also possible via the process data bit "Disable calibration". Version: 1.3.1 ELX3351...

  • Page 61: Command Object

    0x00 (0 7000:05 Tare The process record can be set to 0 with a rising BOOLEAN 0x00 (0 edge. The tare value is not stored in the EEPROM and is therefore no longer available after a terminal reset. ELX3351 Version: 1.3.1...

  • Page 62: Information / Diagnostic Data

    Index (hex) Name Meaning Data type Flags Default 1008:0 Device name Device name of the EtherCAT slave STRING ELX3351 Index 1009 Hardware version Index (hex) Name Meaning Data type Flags Default 1009:0 Hardware version Hardware version of the EtherCAT slave...
  • Page 63 0x06 (6 Value (Real) 1802:06 Exclude TxPDOs Specifies the TxPDOs (index of TxPDO mapping ob- OCTET- 01 1A 04 1A 05 jects) that must not be transferred together with Tx- STRING[10] 1A 06 1A 07 1A PDO 3 ELX3351 Version: 1.3.1...
  • Page 64 0x02 (2 1C12:01 Subindex 001 1. allocated RxPDO (contains the index of the associ- UINT16 0x1600 (5632 ated RxPDO mapping object) 1C12:02 Subindex 002 2. allocated RxPDO (contains the index of the associ- UINT16 ated RxPDO mapping object) Version: 1.3.1 ELX3351...
  • Page 65 Shift too short counter Number of occasions that the interval between UINT16 0x0000 (0 SYNC0 and SYNC1 event was too short (DC mode only) 1C32:20 Sync error The synchronization was not correct in the last cycle BOOLEAN 0x00 (0 (outputs were output too late; DC mode only) ELX3351 Version: 1.3.1...
  • Page 66 0x0010 (16 tance nels F000:02 Maximum number of Number of channels UINT16 EL3351-0000: modules 0x0001 (1 EL3351-0090: 0x0002 (2 Index F008 Code word Index (hex) Name Meaning Data type Flags Default F008:0 Code word reserved UINT32 0x00000000 Version: 1.3.1 ELX3351...
  • Page 67 Parameterization and programming Index F010 Module list Index (hex) Name Meaning Data type Flags Default F010:0 Module list Max. subindex UINT8 0x02 (2 F010:01 SubIndex 001 UINT32 0x00000172 (370 F010:02* SubIndex 002 UINT32 0x000003B6 (950 *) ELX3351-0090 only ELX3351 Version: 1.3.1...

  • Page 68: Appendix

    Beckhoff EtherCAT modules are intended for use with Beckhoff’s UL Listed EtherCAT Sys- tem only. Examination For cULus examination, the Beckhoff I/O System has only been investigated for risk of fire and electrical shock (in accordance with UL508 and CSA C22.2 No. 142). For devices with Ethernet connectors Not for connection to telecommunication circuits.

  • Page 69: Support And Service

    Beckhoff's branch offices and representatives Please contact your Beckhoff branch office or representative for local support and service on Beckhoff products! The addresses of Beckhoff's branch offices and representatives round the world can be found on her internet pages: http://www.beckhoff.com You will also find further documentation for Beckhoff components there.
  • Page 70 Connecting a cable on a terminal point ..................Fig. 17 ELX3351 - Contact assignment ....................Fig. 18 ELX3351 - Connection of a full bridge in 6-wire technology ............Fig. 19 Strain gauge ..........................Fig. 20 quarter, half, and full bridge ......................
  • Page 71 Diagram signal delay (step response) ..................Fig. 44 Diagram signal delay (linear) ....................... Fig. 45 ELX3351 – process data selection in the TwinCAT System Manager ........Fig. 46 ELX3351 - selection Predefined PDO Assignment..............Fig. 47 ELX3351 - Default process image ....................

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