Belimo pluggable auxiliary switch 2x changeover contact - S1A

Belimo Plug-on Auxiliary Switch 2x SPDT - S1A

The Belimo S2A auxiliary switch is a compact expansion module for damper and rotary actuators, allowing you to easily add additional switching functions or position feedback. The module monitors the actuator’s position and translates this into electrical switching points. This enables, for example, monitoring ventilation positions, controlling systems, or sending signals to a building management system. Thanks to the direct coupling with the actuator, switching is precise across the entire rotation range.

Benefits and Features

• Double switching: two potential-free SPDT contacts enable multiple signals or switch functions to be implemented simultaneously
• Flexible adjustment: freely adjustable switching points across the full range provide maximum flexibility in control and monitoring
• Direct feedback: mechanical coupling with the actuator ensures reliable and accurate switching points
• Easy adjustment: visual setting with a scale allows quick and reproducible calibration
• Wide applicability: suitable for both AC and DC voltages across various control technology applications
• Quick connection: pre-wired with 1 metre cable for neat and efficient installation

Performance and Practical Experience

In practice, the auxiliary switch provides a stable and precise switching function regardless of the actuator position. The adjustable switching points from 0 to 100% of the stroke give you full control over when a signal is issued. This is particularly valuable for air dampers and control valves where exact position feedback is essential for properly functioning installations. The switching capacity of up to 3 A and support for both low and higher voltages make the module suitable for various control and signalling applications. The mechanical transmission directly translates the position without delay or deviation.

Installation, Maintenance, and Applications

The auxiliary switch is mounted directly onto the actuator via the clamp ring or position indicator, eliminating the need for additional mounting brackets. Guide grooves ensure correct and well-sealed positioning, contributing to an IP54 protection rating. During installation, you can easily set the switching points using the rotary knobs while the actual position remains visually readable. The unit is maintenance-free and designed for long-term use under variable conditions, with an operating temperature range from -30 to +50 °C. This makes the auxiliary switch ideal for HVAC applications in commercial and industrial sectors where reliability and easy integration are essential.