Specifications

Setting Flow Sensor Factors
13
Siemens Industry, Inc.
140-0893 Start-up
Draft
1/12/2010
Setting Flow Sensor Factors
The BACnet ATEC models 2301 and 0001 use mass airflow sensors to measure duct
differential pressure. A differential pressure calibrated sensor is used over mass flow to
make the sensor compatible with previous controller designs. Since the flow
measurement is done based on the mass of the air, the BACnet ATEC has several
new parameters that can/should be adjusted to help reduce airflow measurement
errors.
The new setup points are:
 (1) altitude, AIR ALTITUDE, [default is 700 feet],
 (2) airflow pickup to airflow sensor total tubing length, TUBE LEN, (to and from
pickup) [default is 6 feet]
 (3) inside tubing diameter, TUBE DIAMETE, [default is 187 inches].
If you only set one of these parameters, it should be the installed altitude of the
controller. This single parameter adds the most effect on sensor error.
NOTE:
The controller goes through a shut-down/load sequence after setting.
Typical correction factor applied to sensor output.