Application Note: AHU VFD Control

Solution:

Using a 75F Edge 10, the CCU can control the vast majority of functions on the AHU while the Edge 10 will provide the duct static pressure control for the supply fans.  The CCU will also provide the fan enable based on occupancy state (including preconditioning) and the duct static pressure reset based on ASHRAE Guildeline 36 Trim & Respond sequences.  The Edge 10 will come pre-programmed for a true plug-and-play experience.  We will also provide parameters for PID Loop tuning so direct access to the Edge 10 is not required.  All points will be viewed and configurable on the CCU and through Facilisight.

Note:

• The CCU will be used for all heating/cooling functions in this configuration.  The CCU provides load based control, not supply air temperature control.
• This solution does not require an internet connection to the Edge 10, only to the CCU.

VFD Points List:

Hardwired Inputs:

• Fan Enable (From G1 on CCU)
• Duct Static Pressure Setpoint (From AO2 on CCU)
• Supply Fan Status (Analog)
• Return Fan Status (Analog)
• Duct Static Pressure

Digital Outputs:

• Supply Fan Enable
• Return Fan Enable

Analog Outputs:

• Supply Fan Speed
• Return Fan Speed

Integrated Inputs

• Duct Static Pressure Reset Setpoints (Min/Max)
• PID Loop Tuning
  • Proportional
  • Integral
  • Derivative
  • Bias
  • Minimum Output
  • Maximum Output
  • Ramp Time (Minutes)
• Supply & Return Fan Speed Output Signal Scale/Offset Configuration
• Return Fan Speed Offset (Supply Fan Speed x Return Fan Speed Offset = Return Fan Speed)