Belimo pluggable auxiliary switch 1x changeover contact - S1A

Belimo Snap-on Auxiliary Switch 1x Changeover Contact - S1A

The Belimo S1A is an auxiliary switch for damper and rotary actuators, allowing you to easily add a switching or position feedback function to an existing actuator. The module mechanically couples onto the actuator’s clamp ring or position indicator and directly converts the current position into an electrical switching signal. This enables monitoring of ventilation positions, control of installations, or transmission of signals to a building management system without the need for an additional position sensor. The switching point is freely adjustable over the entire rotation range of the actuator.

Benefits and Features

• Adjustable switching point: the switching moment is freely adjustable over 0 to 100% of the rotation range, providing maximum flexibility in control and monitoring
• Direct mechanical coupling: the actuator position is converted into an electrical switching signal without delay or deviation
• Wide voltage range: the changeover contact (SPDT) is suitable for both AC and DC voltages, from 5 V DC up to 250 V AC, making it applicable in a wide variety of installations
• Visually readable: the current switch position is always directly visible, simplifying adjustment and verification
• Pre-wired: the switch comes with a 1-metre connection cable for a neat and rapid installation

Accurate Switching Across the Entire Range

The auxiliary switch provides a stable and reliable switching signal regardless of the actuator’s angular position. The switching capacity reaches up to 3 A for alternating current and 0.5 A for inductive loads, making the module suitable for a wide range of signalling and control circuits. Each setting gives one switching transition, with the arrow indicator on the rotary knob always showing the current switch position. This ensures simple and reproducible adjustment, even during reinstallation or replacement.

Installation, Maintenance, and Applications

The auxiliary switch is mounted directly onto the actuator via the clamp ring (damper actuators) or the position indicator (rotary actuators) without additional brackets or accessories. Guide grooves between the housing and switch ensure correct sealed placement, contributing to an IP54 protection rating. You adjust the switching point voltage-free in three steps: disengage the transmission using the manual override button, turn the actuator to the desired position, and set the auxiliary switch’s rotary knob to the desired switching direction. The unit is maintenance-free and operates reliably in ambient temperatures between -30 and +50 °C. This auxiliary switch is therefore suitable for HVAC applications in both commercial buildings and industry, where position monitoring or switch feedback plays a fundamental role in control technology.