Welcome to the Industrial Automation website!

NameDescriptionContent
XING-Automation
E-mail  
Password  
  
Forgot password?
  Register
当前位置:
  • ABB 3BHE034863R001 UDC920BE01 Analog Input Module
    ❤ Add to collection
  • ABB 3BHE034863R001 UDC920BE01 Analog Input Module

    110V-380V
    5W-130W
    1A-30A
    1 year
    30
    United States, France, Japan, Viet Nam, Australia, Russia, Germany, Italy, Arabia

    3BHE034863R0001 UDC920BE01 is a specialized analog input module developed by ABB for high-precision analog data acquisition needs in industrial sites. It adopts an integrated architecture of "signal conditioning precision conversion data transmission" and is specifically used to convert continuous analog signals (such as 4-20mA current signals, 0-10V voltage signals, etc.) output by field sensors and transmitters into digital signals that can be recognized by the controller, and complete signal filtering, isolation, linearization and other preprocessing processes. As a "data bridge" between the control system and on-site sensing devices, this module abandons the shortcomings of low accuracy and weak anti-interference of traditional acquisition modules. It uses an 18 bit high-precision AD conversion chip and industrial grade signal processing circuit, which can work stably under harsh working conditions such as high temperature, high humidity, and strong electromagnetic interference, accurately capturing subtle changes in process parameters. Its standardized interface design can seamlessly integrate with ABB's full range of control equipment and third-party standard sensors, providing a solid guarantee for the flexible construction and efficient operation of automation systems.

    • ¥9048.00
      ¥9173.00
    • Satisfaction:

      Sales: 0

      Review: 0

    Weight:2.840KG
    • Quantity:
    • (Inventory: 99999)
Description

3BHE034863R0001 UDC920BE01 is a specialized analog input module developed by ABB for high-precision analog data acquisition needs in industrial sites. It adopts an integrated architecture of "signal conditioning precision conversion data transmission" and is specifically used to convert continuous analog signals (such as 4-20mA current signals, 0-10V voltage signals, etc.) output by field sensors and transmitters into digital signals that can be recognized by the controller, and complete signal filtering, isolation, linearization and other preprocessing processes. As a "data bridge" between the control system and on-site sensing devices, this module abandons the shortcomings of low accuracy and weak anti-interference of traditional acquisition modules. It uses an 18 bit high-precision AD conversion chip and industrial grade signal processing circuit, which can work stably under harsh working conditions such as high temperature, high humidity, and strong electromagnetic interference, accurately capturing subtle changes in process parameters. Its standardized interface design can seamlessly integrate with ABB's full range of control equipment and third-party standard sensors, providing a solid guarantee for the flexible construction and efficient operation of automation systems.




ABB 3BHE034863R001 UDC920BE01 Analog Input Module

Product Overview

3BHE034863R0001 UDC920BE01 is a specialized analog input module developed by ABB for high-precision analog data acquisition needs in industrial sites. It adopts an integrated architecture of "signal conditioning precision conversion data transmission" and is specifically used to convert continuous analog signals (such as 4-20mA current signals, 0-10V voltage signals, etc.) output by field sensors and transmitters into digital signals that can be recognized by the controller, and complete signal filtering, isolation, linearization and other preprocessing processes. As a "data bridge" between the control system and on-site sensing devices, this module abandons the shortcomings of low accuracy and weak anti-interference of traditional acquisition modules. It uses an 18 bit high-precision AD conversion chip and industrial grade signal processing circuit, which can work stably under harsh working conditions such as high temperature, high humidity, and strong electromagnetic interference, accurately capturing subtle changes in process parameters. Its standardized interface design can seamlessly integrate with ABB's full range of control equipment and third-party standard sensors, providing a solid guarantee for the flexible construction and efficient operation of automation systems.


Core functional features

1. Ultra high precision signal acquisition, capturing subtle parameter changes

The module core is equipped with an 18 bit high-precision analog-to-digital conversion (AD) chip, combined with ABB's independently developed signal calibration algorithm, to achieve ultra high precision conversion of analog signals. The input accuracy of analog signals can reach ± 0.02% FS, far higher than the level of similar products in the industry. For analog signals of different ranges, the module supports multi range adaptive adjustment and can accurately collect various commonly used analog signals such as 4-20mA, 0-20mA, 0-5V, 0-10V, etc. It can clearly capture small fluctuations in process parameters such as temperature and pressure (such as temperature changes of 0.01 ℃ and pressure fluctuations of 0.01MPa), providing reliable data basis for the control system to achieve fine control, especially suitable for chemical synthesis, semiconductor manufacturing and other scenarios that require extremely high precision of process parameters.

2. Multi channel parallel processing to improve data acquisition efficiency

The module adopts a multi-channel independent signal processing architecture, with 16 independent analog input channels configured. Each channel is isolated and works independently, and can simultaneously collect 16 different types of analog signals without interference or crosstalk between channels. Each channel is equipped with a dedicated signal conditioning circuit and AD conversion unit, supporting parallel data processing. The single channel sampling rate can reach up to 100Hz, and the stable sampling frequency can still be maintained when 16 channels work simultaneously. This can meet the needs of multi parameter synchronous acquisition in large-scale industrial production sites, greatly improving the data acquisition efficiency of the control system and avoiding control delay problems caused by data acquisition lag.

3. Comprehensive signal preprocessing to ensure data reliability

To enhance the reliability and availability of collected data, the module is equipped with a comprehensive signal preprocessing function. In response to potential noise interference during on-site signal transmission, each channel is equipped with multi-stage low-pass filtering circuits and digital filtering algorithms, which can effectively filter out 50Hz/60Hz power frequency interference and high-frequency noise, ensuring signal purity; Support linearization processing of nonlinear sensor signals, directly outputting linearized digital signals that comply with industrial standards, reducing the computational load of the controller; Equipped with signal over range detection and fault diagnosis functions, when the input signal exceeds the set range or the sensor malfunctions, abnormal data can be immediately marked and fault information can be uploaded for timely processing by operation and maintenance personnel.

4. Strengthen anti-interference design and adapt to harsh industrial environments

In response to the complex electromagnetic environment of industrial sites, the module adopts multiple anti-interference technologies to construct a comprehensive protection system. The signal input circuit adopts a 3kV AC optoelectronic isolation design to completely block external interference signals from entering the control system through the signal line, with an isolation resistance of ≥ 100M Ω (500V DC); The power input terminal is equipped with an EMC electromagnetic compatibility filtering module and surge suppression circuit, which can effectively resist interference such as grid voltage fluctuations and lightning surges, and adapt to a wide range of power inputs (DC 24V ± 20%); The circuit board adopts multi-layer copper plating, grounding shielding, adhesive sealing and other processes to enhance the module's resistance to electromagnetic radiation, moisture and dust, ensuring stable operation in a wide temperature range of -25 ℃ -70 ℃, high humidity environment of 5% -95% and strong electromagnetic interference scenarios.

5. Flexible communication adaptation, seamlessly integrated into the control network

Adopting standardized bus interface design, the module supports various industrial communication methods such as PROFIBUS-DP, Modbus RTU, ABB dedicated communication protocol, etc. It can achieve high-speed data exchange with upper level devices such as ABB UDC controller, AC500 PLC, System 800xA control system, etc., with a communication speed of up to 12Mbps. The module supports real-time data upload and online parameter configuration. Operations personnel can remotely set the signal type, range, filtering parameters, etc. of each channel through the upper system, without the need to disassemble the module on site to complete configuration adjustments, greatly improving the efficiency of system debugging and maintenance. At the same time, the module has the function of automatic detection of communication faults. When the communication link is interrupted, the collected data can be temporarily stored and transmitted again after communication is restored to avoid data loss.

6. Modular structure design for easy system integration and expansion

Adopting a standardized DIN rail installation design, the module has a compact volume (typical values of width x height x depth are 35mm x 120mm x 140mm), which can be compactly arranged with other automation components in the control cabinet, saving installation space. The module supports cascading expansion of multiple units, and can achieve centralized networking of up to 32 modules through a dedicated bus interface. After expansion, the system can support synchronous acquisition of up to 512 analog signals, meeting the needs of multi area and multi parameter acquisition in large-scale industrial production sites. This expansion method does not require large-scale modifications to the existing system, and only requires software configuration to complete the integration of new modules, reducing the cost of system upgrades.


Key technical parameters

Number of input channels

16 independent analog input channels, isolated from each other between channels

Support signal types

Current signal: 4-20mA, 0-20mA; Voltage signal: 0-5V, 0-10V, ± 5V, ± 10V

Conversion accuracy

± 0.02% FS (full range), AD conversion resolution of 18 bits

sampling rate

Single channel up to 100Hz, ≥ 10Hz/channel when 16 channels are sampled in parallel

Isolation performance

Optoelectronic isolation between input channels and between input and output, with isolation voltage ≥ 3kV AC/1min

Filtering function

Built in 8th order low-pass filtering circuit, configurable digital filtering parameters, adjustable cutoff frequency from 1Hz to 50Hz

communication interface

1 PROFIBUS-DP interface, 1 RS485 interface (supporting Modbus RTU)

communication rate

PROFIBUS-DP: up to 12Mbps; RS485: up to 115200bps

working power supply

DC 24V ± 20%, power consumption ≤ 15W

working environment

Temperature: -25 ℃ -70 ℃; Humidity: 5% -95% (no condensation); Vibration: ≤ 5g (10-500Hz)

Installation method

Standard 35mm DIN rail installation

Protection level

IP20 (module level), compatible with control cabinets with protection levels of IP54 and above


Typical application scenarios

The 3BHE034863R0001 UDC920BE01 analog input module, with its ultra-high precision, multi-channel, strong anti-interference and other characteristics, is widely used in various industrial scenarios with high requirements for analog acquisition accuracy. Typical applications include:

1. Power industry unit monitoring: In the monitoring system of steam turbine generator units in thermal power plants, the module is responsible for collecting key parameters such as turbine bearing temperature, steam pressure, steam flow rate, and generator stator temperature. Through high-precision data, it provides a basis for unit vibration monitoring and performance optimization; In the control system of the hydroelectric power plant's water turbine generator unit, analog signals such as inlet pressure, speed, and guide vane opening are collected to ensure stable operation of the unit.

2. Reaction process control in the chemical industry: In the chemical synthesis reaction kettle control system, the module accurately collects continuously changing parameters such as temperature, pressure, liquid level, and reaction material concentration inside the reaction kettle, and transmits the data in real time to the main controller to provide accurate basis for the controller to adjust heating power, feed rate, etc., ensuring that the reaction process meets process requirements; In the chemical distillation tower system, parameters such as tray temperature, top pressure, and reflux ratio are collected to achieve precise control of the distillation process.

3. Monitoring of smelting process in the metallurgical industry: In the process of blast furnace ironmaking in steel enterprises, the module collects analog signals such as temperature in various areas of the blast furnace body, top pressure, and gas composition concentration to help operators grasp the real-time smelting status inside the furnace; In the electrolysis process of non-ferrous metals such as aluminum and copper, precise collection of parameters such as electrolytic cell voltage, current density, electrolyte temperature, etc. provides data support for optimizing electrolysis processes and energy conservation and consumption reduction.

4. Semiconductor manufacturing process control: In key processes such as photolithography and deposition in semiconductor chip manufacturing, modules collect high-precision parameters such as temperature, pressure, gas flow rate, and vacuum degree inside the process chamber to ensure the stability of the process environment and improve the yield of chip manufacturing; During the semiconductor packaging testing process, analog signals such as voltage and current are collected from the testing equipment to achieve precise monitoring of the testing process.

5. Production monitoring in the food and pharmaceutical industry: During the sterilization process of food processing, the module accurately collects parameters such as temperature and pressure inside the sterilization kettle to ensure that the sterilization effect meets food safety standards; In the process of drug fermentation and formulation in the pharmaceutical industry, parameters such as fermentation tank temperature, pH value, and dissolved oxygen are collected to ensure the stability and safety of drug production.


Precautions for use

1. Installation environment control: The module should be installed in a dedicated control cabinet to avoid direct exposure to dust, oil, corrosive gases, and direct sunlight; The control cabinet needs to be equipped with a heat dissipation device to ensure that the temperature inside the cabinet is controlled within the range of -25 ℃ to 70 ℃, preventing high temperatures from causing module performance degradation; The installation location should be far away from strong electromagnetic interference sources such as frequency converters and high-power motors, and electromagnetic shielding covers should be installed if necessary.

2. Wiring operation specifications: The module power must be cut off before wiring, and live wiring is strictly prohibited; The signal line should use twisted pair shielded cables, with the shielding layer grounded at one end (grounding resistance ≤ 4 Ω) to avoid interference during signal transmission; Different types of analog signals (such as current signals and voltage signals) should be laid separately to avoid line crossing interference; When wiring, it is necessary to ensure that the wires are firmly connected to the terminals to prevent poor contact from causing abnormal signals.

3. Parameter configuration and calibration: Based on the signal type and range of the connected sensor, accurately configure the parameters of each channel of the module through the upper software (such as signal type, range, filtering frequency, etc.); After the module installation and debugging are completed, it is necessary to use a standard signal source to calibrate the accuracy of each channel to ensure the accuracy of the collected data; Regularly (recommended every six months) recalibrate the module to avoid accuracy drift caused by long-term use.

4. Power configuration requirements: Use a stable DC power supply to power the module. It is recommended to use a redundant power supply with voltage regulation function to ensure that the power supply voltage fluctuation is within the range of DC 24V ± 20%; Surge protectors and power filters should be installed at the power input end to suppress power grid impact and noise interference; The power wiring must strictly distinguish between positive and negative poles, and reverse connection is strictly prohibited to avoid burning out the module.

5. Troubleshooting and maintenance: In daily operation, real-time monitoring of the data status of each channel of the module is required through the upper system. When data abnormalities occur, first check whether the sensors are normal and whether the wiring is loose, and then troubleshoot the module; When a module malfunctions, the power should be cut off before maintenance, and it is strictly prohibited to plug or unplug modules with power on; Regularly clean the surface dust of the module, check the fastening and corrosion status of the wiring terminals, and promptly address potential hazards.

6. Communication network guarantee: When configuring communication parameters, it is necessary to ensure that the communication address, speed, and verification method of the module are consistent with the upper system to avoid communication conflicts; Communication lines should use shielded cables and be laid away from power lines; Regularly check the connection status of communication links, promptly address issues such as line aging and poor contact, and ensure stable data transmission.

  • User name Member Level Quantity Specification Purchase Date
  • Satisfaction :
No evaluation information
  • ADLINK AmITX-SL-G Mini ITX Motherboard Deployment and SEMA Guide
  • ADLINK AmITX-AL-I Embedded Motherboard Deployment and SEMA Management Guide
  • ADLINK NuPRO-E315 PICMG 1.3 Industrial Motherboard Deployment Guide
  • ADLINK NuPRO-842 Pentium 4 Industrial Motherboard Deployment and Debugging Guide
  • ADLINK NuPRO-900A Dual Xeon ePCI-X Motherboard Deployment Guide
  • ADLINK cPCI-6910 Dual Core Xeon Single Board Computer Deployment Guide
  • ADLINK cPCI-6860A Dual Xeon Single Board Computer Deployment Guide
  • ADLINK CPCI-8168 Eight Axis Motion Control Card Deployment and HSL Integration Guide
  • ADLINK NuPRO-E340 Industrial Motherboard Debugging and BIOS Optimization Guide
  • ADLINK NuPRO-A40H Industrial Single Board Computer Hardware Deployment and BIOS Calibration Guide
  • ADLINK NuPRO-852 LGA775 Industrial Control Motherboard Maintenance Guide
  • ADLINK NuPRO-841 Industrial Motherboard Maintenance and Troubleshooting
  • ADLINK NuPRO-590 Series Socket7 Industrial Control Motherboard Maintenance Guide
  • Deployment and Troubleshooting of ADLINK MXE-5500 Series Industrial Control Computer
  • ADLINK MXE-200 Fanless Embedded Industrial Control Computer Deployment Guide
  • ADLINK cPCI-6770 Series CompactPCI Motherboard Maintenance Guide
  • ADLINK NuPRO-A301 Industrial Motherboard Troubleshooting Manual
  • ADLINK NuPRO-965 SHB Debugging and Maintenance Complete Manual
  • ADLINK NuPRO-935A Industrial Motherboard Debugging and Maintenance Guide
  • ADLINK NuPRO-865 Single Board Computer Hardware Troubleshooting Guide
  • ADLINK NuPRO-840 P4 Industrial SBC Architecture Maintenance
  • ADLINK NuPRO-770 Full length SBC Configuration and Maintenance
  • ADLINK NuPRO-595 Industrial Half length SBC Motherboard Configuration and Maintenance Guide
  • ADLINK cPCI-6840 Series Single Board Computer Installation, Configuration, and Maintenance Guide
  • Foxboro 43AP Pneumatic Controller Technical Specifications and Selection Guide
  • ADLINK cPCI-3720: 3U CompactPCI Low Power Pentium III CPU Module
  • ADLINK NuPRO-E47: PICMG 1.3 13th Generation Core Industrial SHB
  • ADLINK NuPRO-E43: PICMG 1.3 Core 7th Generation Industrial SHB
  • ADLINK NuPRO-780 PICMG Bus Core CPU Card
  • ADLINK cPCI-6965 6U CompactPCI Core Dual Core Single Board Computer
  • ADLINK USB/LPCI/LPCIe-3488A GPIB Interface Card Selection and Application Guide
  • Rittal SK 3241.700 Blue e+Cabinet Fan Filter Unit
  • ADLINK CPCI-8168 8-Axis Motion Control Card and HSL Network Integration Solution
  • ADLINK PCIe-PXIe-8638 High Speed PXIe Bus Expansion Scheme
  • ADLINK PCIe GIE7x Poe+Frame Grabber Hardware and Power Management Detailed Explanation
  • ADLINK PCIe-7396 Digital I/O Card Deployment Guide
  • ADLINK PCI-8164 Advanced Motion Control Card Deployment Guide
  • ADLINK PCI-8154 Motion Control Card Deployment Guide
  • ADLINK PCI-8134 Motion Control Card Deployment Guide
  • ADLINK NuPRO-E42 Industrial Control Motherboard Deployment Guide
  • ADLINK MXC-6600 Embedded Platform Deployment Guide
  • ADLINK MXC-6000 Industrial Control Computer Deployment and Optimization Guide
  • ADLINK MXC-2300 Embedded System Deployment Guide
  • ADLINK MCM-204 Edge DAQ Deployment Configuration Guide
  • ADLINK MCM-100/102 Deployment Calibration Guide
  • Deployment and Performance Optimization of ADLINK MXC-6400 Industrial Control Computer
  • Selection and Deployment of ADLINK Matrix Series Industrial Control Computers
  • российские промышленные новые машины.Наш отдел дебютировал в 2026 году в России Международная промышленная ярмарка INNOPROM
  • Deeply cultivating the Eurasian industrial market, linking new industrial opportunities between China and Russia
  • Deployment and troubleshooting of ADLINK GIE64+PoE acquisition card
  • Honeywell UMS Security System Troubleshooting Guide
  • Honeywell Expert Series C I/O Troubleshooting Guide
  • ADLINK EOS-1200 Vision System Deployment and Troubleshooting
  • ADLINK DLAP-5200 series AI engine deployment and optimization
  • ADLINK DLAP-4000 Deployment and BIOS Optimization
  • ADLINK Matrix MXC-2000 Deployment and Troubleshooting
  • ADLINK DAQe-2000 series acquisition card calibration and synchronization
  • ADLINK cPCI-6520 Core i7 Processor Blade Engineering Application Guide
  • ADLINK CM1-86DX3 PC/104 Embedded Single Board Computer Engineering Application Guide
  • Honeywell DC1000 Series PID Temperature Controller Engineering Application Guide
  • ALSTOM MiCOM C264 Substation Controller Engineering Application Guide
  • EMERSON AMS 2140 Practical Guide for On site Dynamic Balance and Vibration Analysis
  • ADLINK NuPRO-E320 motherboard deployment and tuning guide
  • ADLINK NuPRO-800 Dual PIII Industrial SBC Maintenance and Upgrade Guide
  • ADLINK NuPRO-598 SBC Maintenance Practical Guide
  • ADLINK MXC-6300 Fanless Embedded Industrial Control Computer Deployment Guide
  • ADLINK Express-BASE7 Carrier Board Quick Deployment and Debugging Guide
  • ADLINK DLAP-211 Edge AI Platform Selection and Deployment Guide
  • ADLINK 7230 Series Isolation DIO Card Selection and Engineering Application Guide
  • ADLINK cPCI-6965 SBC Embedded Installation and BIOS Tuning Guide
  • ADLINK 7200 Series High Speed DIO Card Practical Guide
  • ADLINK DLAP Series Edge AI Acceleration Platform Selection and Deployment Practical Guide
  • DEIF TCM-2 thyristor control module: Wind power cut in control engineering guide
  • DEIF MVR-200 Medium Voltage Relay: Installation and Wiring Engineering Guide
  • DEIF MDR-2 Differential Relay: Engineering Guide for Generator Differential Protection
  • DEIF Delomatic 3 AOM: Engineering Guide for Analog Output Modules
  • DEIF AGI 400 Graphic Interface: Ship and Industrial HMI Solution
  • DEIF BRW-1 Marine Instruments: Installation and Calibration Guide for Offshore Bridge Indicators
  • DEIF AGC 200 Controller: Quick Deployment and Configuration Guide for Generator Sets
  • DEIF AGC-2 Controller: The Ultimate Guide to Automatic Control and Protection of Generator Sets
  • ABB SPA-ZC400 Gateway: REM54x Access to IEC 61850 Ultimate Engineering Guide
  • ABB REM 543/545 Terminal
  • Modular Architecture Analysis of DEIF PPU 300 Ship Generator Controller
  • DEIF DM-4 Marine&Offshore Ship Power Management System
  • Detailed Explanation of DEIF Delomatic Generator Control System Architecture
  • DEIF AGC-4 Mk II Generator Controller Depth Configuration Guide
  • DEIF AGC-4 Generator Controller Configuration and Debugging Guide
  • DEIF PPM Power Management System Operation and Troubleshooting
  • Installation and wiring of DEIF Multi line 2
  • Practical configuration and maintenance of Beckwith M-6280 capacitor bank controller
  • Beckwith M-3311 Transformer Protection Relay Setting and Engineering Application
  • Beckwith M-3311A Transformer Protection Relay Configuration and Optimization Guide
  • Beckwith M-3310 Transformer Protection Relay Complete Guide
  • Beckwith M-0359 synchronous inspection relay
  • Beckwith M-0293A Voltage Regulating Controller Replacement and Debugging Guide
  • Complete Guide to DEIF GPU-3 Generator Protection Unit
  • Installation and I/O configuration of DEIF PPM-3 power management module
  • Beckwith M-3520 Interconnection Protection Relay
  • Beckwith M-3430 Generator Protection Relay
  • Beckwith M-2293B adapter panel replacement GE regulator guide
  • Selection and Networking of Beckwith M-2001C Digital Voltage Regulating Controller
  • Beckwith M-2001B Digital Voltage Regulating Controller
  • Beckwith M-0388/M-0389 Synchronous Inspection Relay Application Guide
  • Beckwith M-0193B Synchronizer Debugging and System Integration Guide
  • Beckwith M-0115A Parallel Balance Module Debugging Guide
  • Beckwith M-0067E On Load Voltage Regulating Controller Selection and Debugging Guide
  • Debugging and Fault Handling of Beckwith M-4272 Digital Busbar Conversion System
  • Beckwith M-3311A Transformer Protection Relay Debugging Guide
  • Beckwith M-3425A Generator Protection Relay Debugging Guide
  • Setting and troubleshooting of Basler BE1-27/59 voltage relay
  • Debugging and troubleshooting of Basler AVC63-12/AVC125-10 voltage regulator
  • Basler L301kc Line Array Camera Technology and Troubleshooting
  • Selection and Debugging of Basler CBS 212A Current Boosting System
  • Selection and commissioning of Basler BE3-25 synchronous inspection relay
  • Basler BE1-32R/32O/U Direction Power Relay Setting and Testing Guide
  • Basler PRS 250 Synchronous Relay Maintenance and Replacement Guide
  • Basler piA2400-17gc Industrial Camera Replacement and Optimization Guide
  • Basler BE1-11g Generator Protection System
  • Basler VR63-4C/UL Voltage Regulator
  • Basler BE1-DFPR feeder protection relay
  • Basler CBS 310/320 Current Boosting System
  • Basler UFOV 250A/260A protection module
  • Basler MVC104/MVC108/MVC232 manual voltage control device
  • Basler XR2002/XR2002F Regulator
  • Basler DECS-400 excitation system
  • Basler DGC-2020 Generator Set Controller: Integrated Control and Debugging Guide
  • Basler MVC-300 Manual Voltage Controller: Characteristics and Engineering Applications
  • Basler MVC Series Manual Voltage Controller: Application and Selection