Functional Devices RIB RIBX24SBA Sensor Relay

The Functional Devices RIBX24SBA is a versatile enclosed current-sensing relay designed for demanding building automation and HVAC industrial control applications. This device combines a solid-state current sensor with a 20A Form C (SPDT) relay, offering an integrated relay-in-a-box solution that simplifies wiring for fan status monitoring and load control. The adjustable threshold range (0.5 to 20 Amps) allows for precise calibration, making it ideal for detecting belt loss or coupling failure in centrifugal pumps and air handlers. Featuring a 24 VAC/DC coil for logic-level activation, it also includes a physical hand-off-auto (HOA) switch for manual override during commissioning or maintenance. The NEMA 1 enclosure ensures protection for internal components while providing a 1/2" NPT nipple for direct mounting to electrical boxes. By replacing multiple discrete components, the RIBX24SBA reduces installation footprint and point-to-point wiring labor for contractors managing BAS systems and motor control centers.

Key Benefits for Contractors

• Dual-Function Design: Integrates a sensing ring and a high-capacity 20A relay into a single housing, eliminating the need for external secondary relays.
• Integrated HOA Switch: Facilitates rapid troubleshooting and system testing without requiring a controller signal.
• LED Indicators: Visual confirmation of relay coil status and current sensor trip point for faster diagnostics.
• Adjustable Trip Point: Multi-turn potentiometer allows fine-tuning for specific motor loads to ensure accurate status feedback.
• Flexible Mounting: The pre-wired design and threaded nipple allow for easy attachment to conduit or control panels.

Common Questions

How do I calibrate the current sensor for belt loss detection?
With the motor running under normal load, adjust the potentiometer until the sensing LED illuminates. Then, turn the adjustment slightly further to compensate for minor voltage fluctuations. If the belt breaks, the drop in amperage will trip the sensor, notifying the BAS.

Can the RIBX24SBA be used with VFD applications?
Yes, but typically it should be installed on the line side of the VFD to avoid false trips caused by variable frequencies, unless the VFD is operating within the sensor's specified frequency range.

What is the maximum current the sensing ring can handle?
The internal sensing ring is rated for up to 20 Amps. For higher amperage loads, a separate current transformer (CT) must be used to step down the current before passing it through the RIB sensor.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.