Beckhoff EL3602 EtherCAT Terminal 2-channel High-Precision Analog Input Module

Description

Designed for high-accuracy voltage measurement within automated control topologies, the Beckhoff EL3602 is a dual-channel analog input terminal operating on the EtherCAT protocol. This high-precision module processes differential input signals across several user-configurable voltage ranges, providing reliable 24-bit resolution to the central control system. Optimized for applications requiring exceptional signal fidelity, it features electrical isolation and robust integrated filters to manage electrical noise in demanding industrial environments.

Features

• Two independent, differential analog input channels.
• Parameterizable measurement ranges: +/-10 V, +/-5 V, +/-2.5 V, and +/-1.25 V.
• Exceptional 24-bit resolution (including sign) for microscopic voltage tracking.
• Extremely low measurement error of less than +/-0.01 percent at 25 degC (relative to full scale).
• Galvanic isolation of 500 V between the internal E-bus and the input channels.
• Configurable conversion times ranging from 1 ms to 400 ms (20 ms default).

Applications

• High-precision automated test benches and calibration systems.
• Process monitoring in semiconductor manufacturing and laboratory environments.
• Tension and load monitoring loops requiring highly stable differential voltage feedback.
• Multi-axis motion systems needing micro-positioning analog feedback.

Technical Specifications

Connections and Interfaces

Empirical Engineering Insights

Alternative Models & Compatibility

When replacing or integrating the EL3602, verify the TwinCAT software version and active EtherCAT XML Device Description (ESI) files. The EL3602 features dynamic configuration via CoE (CAN over EtherCAT) variables. Ensure that older systems designed for the calibrated alternative EL3602-0010 are checked, as scaling and calibration coefficients differ within the PLC program. When using multiple EL series modules, verify that the total E-bus current budget does not exceed the limits of the coupler or the power supply terminal; the EL3602 draws a sustained 190 mA from the E-bus.

Application Pitfalls & Engineering Notes

The common-mode voltage (Ucm) must be kept strictly below 35 V relative to the internal E-bus ground to prevent measurement errors and potential damage. Ground loops are the primary source of drift in 24-bit applications. If measuring floating voltage sources, ensure the AGND terminal is linked to a clean, stable system reference to prevent the differential inputs from drifting into saturation. Additionally, allow a 15-minute thermal stabilization period after powering the cabinet to ensure the internal reference reaches equilibrium for 24-bit resolution stability.

Commissioning & Wiring Tips

Use twisted-pair shielded cabling for all analog signals. The shield should be terminated directly at the terminal (Terminal 3 or 7) for best high-frequency performance. In high-interference environments, utilize the TwinCAT system manager to activate the 50 Hz or 60 Hz notch filter inside the module's CoE registers. This significantly attenuates electrical line noise and maintains the module's ultra-low measurement error rating.

Installation Guidelines