Beckhoff EL3174 EtherCAT Terminal Analog Input 4 Channel Multi-Function

The Beckhoff EL3174 is a 4-channel analog input terminal for the EtherCAT industrial Ethernet system. This multi-function terminal accepts both voltage and current signals, with each of the four channels individually configurable through software to match the specific sensor or transmitter connected. The EL3174 supports a wide range of industrial analog signals, making it a flexible choice for data acquisition and process monitoring applications within Beckhoff EtherCAT networks.

Analog Input Specifications

The EL3174 provides four individually parameterizable differential input channels. Each channel can be configured to measure voltage signals in the range of -10/0 to +10 V DC, or current signals in the range of -20/0/+4 to +20 mA. This flexibility allows the same terminal to accept signals from voltage-output sensors, current-output transmitters, and 4-20 mA loop-powered devices without hardware changes. The analog-to-digital converter provides 16-bit resolution, ensuring precise measurement of the input signal across the full range. Voltage measurement input impedance is greater than 200 kΩ, while current measurement input impedance is 85 Ω typical. The conversion type is ADC with oversampling capability, providing noise rejection and stable readings. The input filter bandwidth supports a 5 kHz cutoff frequency for voltage mode.

Configuration and Operation

Each channel of the EL3174 is configured via the CoE (CANopen over EtherCAT) object dictionary using TwinCAT engineering software. Users can set the input range, signal type, and filter parameters independently for each channel. The terminal supports factory calibration stored in the device, eliminating the need for field calibration and ensuring accuracy across the operating temperature range. Physical connection for voltage and current signals is accomplished through different terminal points to separate signal types, requiring proper wiring according to the terminal documentation. Once configured, the measured values are made available to the EtherCAT master as process data, updated at the terminal's sampling rate.

Technical Data

The EL3174 has typical electrical characteristics including conversion time of approximately 175 µs per channel and an ADC type optimized for industrial analog signals. Data width in the EtherCAT process image is 16 bytes for the four input channels. The terminal is powered via the E-Bus from adjacent EtherCAT terminals, requiring no additional external power for its internal electronics. All analog input channels are electrically isolated from the E-Bus system, preventing ground loops and protecting the control system from field-side noise and voltage surges. The terminal supports distributed clocks for synchronization with other EtherCAT devices in systems requiring time-stamped data acquisition.

Physical Design and Installation

The EL3174 conforms to the standard Beckhoff EtherCAT terminal form factor, designed for DIN rail mounting in a control cabinet. The terminal width is 12 mm, allowing high-density installation for multi-channel analog input applications. Screw-type or spring-type connections are available depending on the terminal variant (EL3174-0000 or EL3174-0002). The terminal operating temperature range is 0°C to 55°C, appropriate for installation within industrial control environments. The terminal is IP20 rated, requiring installation inside a cabinet for protection against dust and moisture. The terminal has LED indicators for power and bus communication status, facilitating troubleshooting and commissioning.

Integration with EtherCAT Systems

The EL3174 is designed for use with any EtherCAT master, including Beckhoff CX and CX20 series embedded PCs, as well as third-party EtherCAT controllers. Configuration is performed using TwinCAT System Manager or other EtherCAT configuration tools, where users assign the terminal to the EtherCAT bus and access process data mapping. The terminal supports advanced features such as limit value monitoring, scaling, and smoothing filters configured through the CoE object directory. The terminal is compatible with the EtherCAT protocol standard and can be integrated into larger EtherCAT networks with hundreds of other terminals and drives.

Applications in Industrial Automation

The EL3174 is suitable for applications requiring multi-channel analog input with flexible signal type support. Typical uses include monitoring pressure, temperature, flow, and level from industrial transmitters, acquiring analog signals from sensors with 0-10 V or 4-20 mA outputs, retrofitting legacy signal sources into EtherCAT systems, and factory automation test stands requiring data acquisition. Industries using the EL3174 include automotive manufacturing for process monitoring, packaging machinery for sensor integration, material handling for conveyor monitoring, and general factory automation for analog I/O expansion.

Conclusion

The Beckhoff EL3174 EtherCAT analog input terminal delivers four individually configurable channels for voltage and current signals. Its 16-bit resolution, differential inputs, and per-channel configuration flexibility make it a suitable choice for EtherCAT-based data acquisition in industrial automation environments.