Beckhoff KS4418 KS Series 8-Channel Analog Output Bus Terminal

Description

Engineered for high-density electrical cabinets, the Beckhoff KS4418 delivers eight independently operating analog output channels designed to transmit 0 to 20 mA signals to field actuators. This terminal combines a highly compact 12 mm form factor with a specialized pluggable wiring level, enabling rapid system maintenance and module hot-swapping without disturbing field terminations. Utilizing single-ended technology and a 12-bit digital-to-analog converter, it provides reliable setpoint transmission for valves, actuators, and speed controllers across K-bus architectures.

Features

• Eight Analog Channels: High packing density allows independent 0 to 20 mA control loops within a single 12 mm wide housing.
• Pluggable Wiring Interface: The KS-series design incorporates a detachable terminal connection level, reducing downtime during field maintenance.
• Galvanic Isolation: Complete 500 V electrical isolation between the internal K-bus and the process-side signals prevents ground loops.
• Precise Signal Conversion: Integrated 12-bit conversion delivers output accuracy within plus/minus 0.2% of the full-scale value.
• Rugged Housing Design: Enclosed in robust polycarbonate with secure double-slot and key side-by-side mounting mechanisms.

Applications

• Proportional Valve Control: Delivering continuous analog setpoints to hydraulic and pneumatic pressure regulating valves.
• Variable Frequency Drive Interfacing: Transmitting precise motor speed and torque setpoints to motor control centers.
• Process Plant Automation: Integration into chemical, pharmaceutical, and water treatment plants requiring localized analog current loops.
• OEM Machine Building: High-density I/O configuration in standard control panels where physical rail space is highly restricted.

Technical Specifications

Empirical Engineering Insights

Alternative Models & Compatibility

The terminal is functionally identical to the standard Beckhoff KL4418 bus terminal. The core architectural distinction is the pluggable terminal block of the KS-series (KS4418), which enables swift electrical hot-swaps of physical units during critical system maintenance without disconnecting field control cables. They utilize identical GSD and XML device description files inside TwinCAT or alternate fieldbus master software configurations.

Application Pitfalls & Engineering Notes

Special attention must be paid to loop resistance constraints. With a maximum load capacity of 150 Ohms, deploying long wire runs or high-impedance field instruments may exceed the voltage compliance limits of the internal driver circuits. Exceeding 150 Ohms will cause output current saturation below the required 20 mA signal level, resulting in measurement deviations and system tracking errors without necessarily triggering a hardware fault code.

Commissioning & Wiring Tips

To maintain output accuracy within the rated plus/minus 0.2% tolerance under heavy electromagnetic environments, we recommend installing twisted-pair shielded cables (STP) for all 8 analog channels. Ensure the cable shield is cleanly terminated to the earth grounding rail at the control panel entry point. To avoid ground loops with single-ended outputs, confirm that the ground references of connected external devices match the local module ground potential.

Installation Guidelines