Application Note : Controlling a VCCX (AAON Control Board) with the CCU

Problem:

In some cases, AAON units do not have 3rd Party terminal strip connections to control the unit and offer a VCCX2 Controller that offers either BMS Controls (BACNet MSTP) or terminations for external control of :

• Remote Occupancy
• Supply Air Temperature Reset

Solution:

Without adding the cost of a standard system level controller (JACE, Edge10, HoneyWell, JCI), 75F is able to use the CCU to control the aforementioned points with minimal programming and configuration while providing a dry contact and 0-10VDC control signal to the controller. 

CCU Configuration:

• System Profile will be set to 'VAV Advanced Hybrid AHU'.
• Enable :
  • Relay-3 (G / Fan Stage 1), Analog-Out1(AO4 / Composite Signal).
• Composite Signal Configuration :
  • Analog-Out4 at Min Cooling = 6V, Analog-Out4 at Max Cooling = 10V
  • Analog-Out4 at Min Heating = 5V, Analog-Out4 at Max Heating = 0V.

AAON VCCX Configuration: 

• What voltage will correspond to the Low SAT Setpoint
  and what voltage will correspond to the High SAT Setpoint in both
  the Heating and the Cooling Modes.
  • Per the Manual : When the Reset Source is at its highest configured setpoint, the SAT
    Setpoint will be reset to its lowest configured setpoint. When the Reset Source is at its lowest configured setpoint, the SAT Setpoint will be reset to its highest configured setpoint. In all cases, as the Reset Source value moves within its range established by the configured High and Low Reset Setpoints, the Supply Air Setpoint will be proportionally reset within its range established by the configured Low and High SAT Setpoints. If a Remote SAT Reset Signal is configured as the Reset Source, a configurable voltage signal (between 0 and 10 VDC, direct or reverse acting) can be used to reset the Supply Air Temperature Setpoint.

References :

TBD