RPX

BTU has developed the RPX, an innovative rack and pinion door control system that is the first in the industry to offer variable speed control. As the demand for more precise control increases, the RPX system allows individual doors to adjust their speed based on ambient temperature. For example, in colder conditions, the doors operate more slowly, while in warmer conditions, they move faster. Traditional linear actuator controls often experience issues with relays that drive the actuators and the wear on DC motor brushes. DC motors typically face a significant inrush of current at startup, which places unnecessary strain on both the motor and the relays that control them.

The new RPX eliminates this problem by using solid-state motor controls, removing the need for relays altogether. The RPX card serves as the interface for limit switches and provides door position feedback through an encoder. It is capable of controlling up to eight fresh air doors across three different stages, enabling precise and flexible door operation management. Additionally, the RPX can automatically operate bypass doors for both the evaporator and the evaporative cooler. When the equipment is not in use, the system opens the bypass doors to reduce back pressure, improving airflow and increasing volume efficiency. This advanced system delivers smoother, more reliable, and more precise performance, expanding its range of use cases while offering enhanced durability compared to the SDX and other fresh air door controls.

The RPX remains in constat communication with the BTU XT control system, receiving real-time updates on outdoor temperature and humidity conditions. Using this data, it dynamically adjusts door speed and positioning to maintain precise environmental control. In the event of a temporary manual shutdown, whether minutes or hours long, the RPX retains positional awareness through continuous system communication. When the system resumes normal operation, the doors immediately return to their calculated target position, allowing the system to restore cooling performance and return to setpoint as quickly and efficiently as possible.