Setup and Operation for AMS and AMD Series Without Factory Supplied
Controller
Label 1: AMD/AMS Label
Each AMD and AMS is shipped with a highly accurate pressure transducer (+/- 0.25% of range) that results in
optimal airflow measurement accuracy (see
Figure 1
).The pressure transducer outputs a 0-10 VDC signal that is
proportional to the pressure measured by the airflow station. The high pressure limit of the transducer is set at the
factory to optimize the resolution of the reading. The selection is based on the maximum velocity of the application
that was selected at the time the unit was ordered. The selected transducer range is listed on a label affixed to the
AMD or AMS (see example label below). Using the high pressure limit of the transducer and the voltage output of the
transducer the real-time pressure reading can be calculated using the formula:
P
transducer
= (Transducer Output Voltage) * (High Pressure Limit of Transducer) / 10
Formula 1
The pressure reading of the transducer can then be used to calculate the volumetric flow rate going through the
AMS or AMD using the formula:
Q
SC
= Damper Area*K*( P
transducer
)
m
where Q
SC
= cfm at standard air conditions
Formula 2
The K & m values are damper specific constants that are listed on the label. The area of the damper is also listed on
the label.
Figure 1: BAPI transducer
PI
d
Formula 2 calculates the cfm at “standard air conditions”. To correct the cfm value to the air density on the job (Q
SITE)
)
use the formula and air density correction factor (cf) shown below.
Q
SITE
= cf * Q
SC
Formula 3
AMD & AMS Series
4
®
