Greenheck AMD Series Dampers (474014) - Manual (Page 4)

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Setup and Operation for AMS and AMD Series With Factory Supplied Controller cont..
Units ordered with a factory controller are supplied with a Greenheck Vari-Green constant volume controller. The Vari-Green
constant volume controller is highly configurable, but is shipped from the factory preprogramed as ordered for and thus does
not normally required field configuration. The full installation and operation manual for the controller is available at
http://
www.greenheck.com/products/detail/91 under the Instruction Manual tab.
In its default operating mode the controller will modulate the damper’s actuator to achieve a cfm setpoint. The controller
receives the cfm setpoint via an analog input. The controller also has an analog output that is proportional to the real-time
cfm that is going through the AMS/AMD. The following section describes how to determine the voltage corresponding to the
desired cfm setpoint and how to convert the voltage output into cfm.
Setting the Flow Setpoint
The controller accepts an analog input (configurable for either 0-10 or 2-10 VDC) that is proportional to a target volumetric
airflow rate (cfm). The voltage corresponding to the setpoint can be determined using the following formulas:
0-10 VDC setpoint
C = Q /(Vmax * A) *10
2-10 VDC setpoint
C = Q /(Vmax * A) *8 + 2
Formula 3
Where:
C = Flow Setpoint (VDC)
Q = Desired Airflow (cfm)
V max = Maximum Velocity as specified at the time the unit was ordered (fpm)
A = Face Area of the Damper (ft2)
Note that Vmax and A are found on the label affixed to the AMD/AMS next to the transducer (see Label 2)
Example: The BMS desires 6,000 cfm through a 24 in. x 24 in. AMD-42 that was ordered with a maximum velocity of 2,000
fpm. Find the voltage setpoint that corresponds to 6,000 cfm:
C = 6,000 / (2,000 * 4) * 10 = 7.5VDC (0-10 VDC)
C = 6,000 / (2,000 * 4) * 8 +2 = 8 VDC (2-10 VDC)
Controller’s Analog Output Proportional to Real-Time Airflow
The controller outputs an analog signal (configurable for either 0-10 or 2-10 VDC) that is proportional to the real-time airflow
rate (cfm) going through the AMD/AMS. The cfm corresponding to the voltage output can be determined using the following
formulas:
0-10 VDC output
Q = (C * Vmax * A) / 10
2-10 VDC output
Q = ((C-2) * Vmax * A) / 8
Formula 4
Constant Volume
Varigreen Damper
Controller