KL3052 Beckhoff 2-Channel Loop-Powered Analog Input Terminal (4–20 mA)

Product Overview

The KL3052 (KL3052) is a high-performance 2-channel analog input terminal designed for the Beckhoff Bus Terminal system to process standard 4 to 20 mA signals. Specifically engineered for efficiency, this module is a loop-powered terminal, meaning it provides the necessary 24 VDC sensor supply directly through its power contacts. This feature significantly simplifies field wiring by eliminating the need for separate power distribution blocks for your transmitters. With a 12-bit resolution, the KL3052 is an ideal solution for monitoring pressure, level, and temperature sensors in water treatment, chemical processing, and general factory automation.

Functional Engineering & Power Logic

The Beckhoff KL3052 utilizes single-ended technology to deliver accurate current measurements with a fast conversion time of approximately 1 ms to 2 ms. Because the module integrates the sensor supply, it acts as the power source for the 4–20 mA current loop. The internal circuitry includes a low-impedance shunt (80 Ω + 0.7 V) and is protected against surge voltages up to 35 V. Like all Beckhoff Bus Terminals, it features 500 V electrical isolation between the field signals and the K-bus, ensuring that localized electrical noise or ground faults do not propagate to the central PLC or Bus Coupler.

Technical Specifications

Technical FAQs

What is the benefit of a "Loop-Powered" terminal with sensor supply?

In a standard current loop, you would normally need an external power supply to "drive" the 4–20 mA signal from the sensor. The KL3052 provides this 24 VDC internally. This reduces the number of wires going to the field and reduces the density of components in your control cabinet, leading to lower installation costs and fewer points of failure.

How is the data represented in the PLC process image?

The measured 4–20 mA signal is mapped as 2 x 16-bit data in the process image. While the resolution is 12-bit, the data is typically formatted so that 4 mA corresponds to a specific digital value (e.g., 0 or a standardized offset) and 20 mA corresponds to the maximum value, allowing for easy scaling in TwinCAT or other programming environments.

Can the KL3052 detect a wire break?

Yes. Because the module operates on a 4–20 mA "live zero" scale, any signal falling significantly below 4 mA (typically near 0 mA) is instantly recognizable by the PLC as a wire break or sensor failure, enhancing the functional safety of the system.

Field Engineering & Installation Guide

• Power Contact Integrity: Since the KL3052 draws sensor power from the terminal's internal power contacts, ensure that the preceding terminal in the assembly (typically a Bus Coupler or a Power Feed Terminal like the KL9100) is supplied with a stable 24 VDC.

• Shielding: To maintain the ±0.3% measuring accuracy, use shielded cables for the current loops. The shield should be connected to the functional earth (FE) using Beckhoff shield clamps to mitigate the effects of high-frequency interference.

• Thermal Management: When mounting several KL3052 modules side-by-side, ensure the cabinet has adequate convection. While the module is efficient, the combined sensor supply current across multiple loops can generate localized heat.

Engineering Advantages

The KL3052 is a "workhorse" for B2B industrial projects, offering a ruggedized design that conforms to EN 60068-2-6 for vibration and shock resistance. Its wide array of global approvals, including CE, UL, Ex (for hazardous areas), and GL (for marine applications), makes it a versatile choice for international projects. By integrating the sensor power supply and providing high-speed 12-bit digitization in a 12 mm frame, Beckhoff provides a solution that maximizes panel density without compromising on technical performance or diagnostic clarity.