Beckhoff KL2535 Bus Terminal 2-Channel PWM Output Module

Description

Directing the precise power distribution to inductive loads, the Beckhoff KL2535 represents a high-efficiency 2-channel pulse-width modulation (PWM) output terminal integrated into the robust K-bus architecture. This industrial-grade output terminal is engineered specifically for control applications requiring current-regulated output power, such as proportional valves, solenoids, and magnetic coils. Utilizing high-frequency switching technology, it permits seamless duty-cycle adjustments from 0% to 100% with short-circuit and thermal-overload protection standard across both channels. Designed for DIN-rail deployment, the module maintains a compact form factor while providing galvanically isolated, high-resolution control signals directly from the standard PLC process image.

Key Features

• Dual PWM Outputs: Controls two independent channels rated at 24 V DC with an output current capacity up to 1 A per channel.
• High-Frequency Modulated Control: Operates at a default PWM clock frequency of 36 kHz, ensuring ripple-reduced current stability in inductive loads.
• Comprehensive Self-Protection: Integrated short-circuit protection and cooperative thermal overload shutdown preserve system longevity.
• Robust Galvanic Isolation: Provides up to 500 V electrical isolation between the internal K-bus and the field potential.
• Compact Form Factor: Standard 12 mm bus terminal width optimizes control cabinet real estate.

Applications

• Proportional Valve Control: Modulates pilot valves, hydraulic directional valves, and pneumatic control assemblies.
• Electromagnetic Solenoids: Manages current limits and holding states for heavy-duty industrial relays and linear actuators.
• Thermal Loop Elements: Drives resistive heating elements and cooling fans using high-frequency duty cycles.

Technical Specifications

Connections and Interfaces

Empirical Engineering Insights

Alternative Models & Compatibility

The KL2535 operates within standard Beckhoff K-bus systems. For architectures utilizing EtherCAT protocols, the EL2535 EtherCAT Terminal serves as the natural functional migration path, matching form factors and general electrical outputs but adapting to the EtherCAT E-bus interface. If upgrading older standard terminals, verify that your active Bus Coupler (such as the BK3120, BK9000, or BC9000) is running compatible firmware to parse the 48-bit control and status registers allocated by the KL2535.

Application Pitfalls & Engineering Notes

Thermal integration is a critical factor when driving both channels at their maximum 1 A current limits continuously. Under high ambient temperatures close to the 55 degC limit, proper vertical mounting and standard 10 mm lateral spacing from high-heat components are highly recommended. Note that because the PWM clock operates at 36 kHz, high-frequency current ripples can induce minor inductive heating inside solenoids if the load inductance is lower than 1 mH; verify load parameters prior to continuous cycling.

Commissioning & Wiring Tips

To minimize high-frequency electromagnetic emissions generated by the 36 kHz carrier signal, always utilize twisted-pair, shielded cabling for all load connections. Connect the cable shield directly to the designated PE terminal points (4 and 8) on the KL2535 housing or the system grounding rail. Avoid running output wires parallel to analog sensor cables to prevent crosstalk noise.

Installation Guidelines