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HVAC/R Jan 23, 2025

Why use MS/TP communications in building automation systems?

Ensuring seamless communication between devices is the foundation of efficient and reliable building automation systems. One protocol that continues to demonstrate its utility is BACnet MS/TP. With the RC-FLEXone MS/TP controller, Reliable Controls provides a solution that combines advanced features with the adaptability to integrate into existing BACnet MS/TP networks. But when and why is MS/TP communication helpful in building automation systems?

Understanding BACnet MS/TP

BACnet multidrop serial bus token passing (MS/TP) is a communication protocol designed for building automation and control networks. It enables controllers, sensors, and actuators to communicate over RS-485 twisted-pair cabling using a token-passing scheme. This setup makes MS/TP a reliable and cost-effective choice for many applications, especially in smaller or retrofitted buildings.

Scenarios where MS/TP shines

  • Retrofit projects: Many buildings operate legacy systems that rely on BACnet MS/TP for communication. Upgrading to newer Ethernet-based controllers can be costly and complex and requires extensive rewiring. By incorporating MS/TP-compatible devices like the RC-FLEXone MS/TP controller, you can modernize your system while retaining your existing infrastructure, saving time and money.
  • Cost-sensitive deployments: For smaller facilities or applications with limited budgets, MS/TP offers a cost-effective solution. RS-485 cabling is less expensive to install compared to Ethernet, making MS/TP an attractive option for straightforward deployments where the high-speed capabilities of Ethernet are unnecessary.
  • Simpler system requirements: Not all building automation systems demand high-speed communication. Applications like room temperature control, lighting, or basic HVAC management can operate effectively with the slower speeds of MS/TP. The RC-FLEXone MS/TP controller delivers the reliability and precision needed for these tasks without overcomplicating the network.
  • Distributed systems: In large buildings or campuses, MS/TP’s token-passing protocol ensures efficient communication even when devices are spread across significant distances. This setup minimizes communication conflicts, providing stable and predictable performance in distributed systems.
  • Resilient network design: MS/TP’s token-passing mechanism inherently limits network congestion, making it a dependable option for systems where consistent communication is critical. Additionally, the inclusion of a soft end-of-line switch on the RC-FLEXone ensures good communication integrity by applying the necessary resistance across the network.

 

Advantages of the RC-FLEXone MS/TP controller

The RC-FLEXone MS/TP controller exemplifies how advanced technology can breathe new life into established protocols. Its benefits include:

  • Seamless integrationBackward compatibility with BACnet MS/TP networks ensures easy adoption in retrofits and expansions.
  • Customizable FLEX I/O: Innovative input/output options allow for painless system scaling and adaptation to changing needs.
  • Compact design: The controller’s space-efficient size makes it versatile for various installation scenarios.
  • Reliable performance: A 5-year warranty and the trusted Reliable Controls brand promise durability and long-term dependability.

 

Making the right choice for your building

When deciding between MS/TP and Ethernet communication protocols, it’s essential to consider the specific needs of your building automation system. For facilities with existing MS/TP infrastructure, retrofits, or cost-sensitive projects, MS/TP is a viable option. The RC-FLEXone MS/TP controller bridges the gap between modern functionality and legacy compatibility, ensuring no building is left behind in the drive for smarter, more sustainable operations. By leveraging the strengths of MS/TP communication, you can create a system that’s both efficient and future ready.

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Ready to learn how the RC-FLEXone MS/TP controller can transform your building automation system? Connect with one of our experts today.