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 * V
max
* A) / 10
2-10 VDC output
Q = ((C-2) * V
max
* A) / 8
Formula 4
Where:
C
= Voltage Output Signal (VDC)
Q
= Real-time Airflow (cfm)
V
max
= Maximum Velocity as specified at the time the unit was ordered (fpm)
A
= Face Area of the Damper (ft
2
)
Note that V
max
and A are found on the label affixed to the AMD/AMS next to the transducer (see Label 1)
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 /(V
max
* A) *10
2-10 VDC setpoint
C = Q /(V
max
* 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 (ft
2
)
Note that V
max
and A are found on the label affixed to the AMD/AMS next to the transducer (see Label 1)
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)
AMD & AMS Series
6
®
