Product Overview
The KL2889 (KL2889) is a high-density (HD) 16-channel digital output terminal designed for the Beckhoff Bus Terminal system. This module is specifically engineered for ground-switching (low-side switching) applications, providing 0 V DC output to control actuators, relays, and indicator lamps. By utilizing High-Density packaging, the KL2889 integrates 16 discrete outputs into a slim 12 mm housing, significantly reducing the required DIN rail footprint in complex control cabinets. It is an ideal choice for high-volume I/O environments such as automotive assembly lines and modular packaging machinery, where space efficiency and high-speed point-to-point wiring are paramount.
Technical Configuration
The KL2889 hardware is built for simplicity and reliability within the K-bus architecture. It features a 1-wire connection technology with a direct plug-in technique for solid wire conductors, facilitating rapid tool-less installation. The output stage is designed for 0.5 A per channel and is fully short-circuit proof, featuring an integrated reverse voltage protection mechanism. The terminal maps 16 outputs directly into the process image, requiring no complex address or software configuration. Its 500 V electrical isolation between the K-bus and field potential ensures that the central controller remains protected from field-side electrical transients or inductive flyback during heavy-duty switching cycles.
Technical Specifications
| Feature |
Specification |
| Model |
KL2889 |
| Brand |
BECKHOFF |
| Origin |
Germany |
| Number of Outputs |
16 |
| Switching Type |
0 V DC (Ground switching) |
| Nominal Voltage |
24 VDC (-15 percent / +20 percent) |
| Max. Output Current |
0.5 A per channel |
| Connection Technology |
1-wire (High Density) |
| Breaking Energy |
< 100 mJ / channel |
| Current Consumption (K-bus) |
typ. 45 mA |
| Electrical Isolation |
500 V (K-bus / field potential) |
| Operating Temperature |
0 to +55 Celsius |
| Weight |
approx. 70 g |
Technical FAQs
What is the benefit of "0 V switching" in the KL2889?
Ground switching (NPN style) is often used in specific industrial regions or with certain types of sensors and actuators that share a common positive rail. The KL2889 completes the circuit by connecting the load to the 0 V (ground) potential.
How does the "direct plug-in" technique work?
For solid wire conductors, you can simply push the stripped wire into the terminal point without tools. For stranded wires or those with ferrules, a standard screwdriver is used to actuate the spring, ensuring a gas-tight and vibration-resistant connection.
Can I use this terminal to drive small DC motors?
Yes, provided the motor's steady-state current does not exceed 0.5 A and the inductive breaking energy remains under 100 mJ. For larger inductive loads, an external freewheeling diode is recommended to protect the internal output stage.
Engineering & Installation Guide
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Wiring for HD Terminals: Given the high density of 16 connections in a 12 mm width, it is critical to use the correct wire cross-sections. For optimal results, use ferrules for stranded wires (0.14 to 0.75 mm²) to prevent stray strands from causing short circuits between the tightly packed terminals.
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0 V Potential Management: Ensure that the 0 V field potential is correctly fed into the power contacts. Since this is a ground-switching module, all connected loads must have their positive side connected to a common 24 VDC rail, while the KL2889 manages the ground return path.
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Heat Dissipation: When all 16 channels are active and driving the maximum 0.5 A load, the module generates internal heat. Ensure the control cabinet has adequate ventilation and observe the variable installation positions described in the technical documentation to prevent thermal derating.
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Short-Circuit Handling: While the module is short-circuit proof, a persistent short will trigger the current limitation (< 7 A). It is best practice to monitor the system diagnostic LEDs; if the "Error" LED for a channel bank illuminates, investigate the field wiring immediately to prevent unnecessary stress on the polycarbonate housing.