FMS-2000C
LIT-12013504
36
Configuring the analog input to measure air flow
You can calculate and display the air change rate or display room cfm in AI-2, AI-3 and AI-4 with either a DP transmitter or flow sensor.
In AI-2 only, if you choose to calculate the air changes per hour, you can also select setpoints based on different modes of occupation.
Otherwise there is only one air change rate setpoint available.
Configuring the analog input type to measure air flow
1. On the home screen, tap the
Settings
icon to enter the
Settings
menu.
2. To view analog input settings, tap
Analog I/O
.
3.
To find the analog input you want to adjust, swipe left.
4.
To configure the analog input type for flow, tap the
Type
arrow.
5. On the
Type
screen, scroll to
Flow
.
6.
To confirm the settings, tap the
Checkmark
icon.
Specifying the sensor type to measure air flow
1. On the home screen, tap the
Settings
icon to enter the
Settings
menu.
2. To view analog input settings, tap
Analog I/O
.
3.
To find the analog input you want to adjust, swipe left.
4. Expand the
Sensor Type
and tap one of the following options:
•
DP Transmitter
•
Flow Sensor
5.
To confirm the new settings, collapse
Sensor Type
.
Specifying the maximum input setting to measure air flow
If you are using a DP transmitter, set the maximum pressure input. If you are using a flow sensor, set the maximum flow input.
1. On the home screen, tap the
Settings
icon to enter the
Settings
menu.
2. To view analog input settings, tap
Analog I/O
.
3.
To find the analog input you want to adjust, swipe left.
4. To change the maximum pressure input, tap the
Maximum Pressure Input
arrow.
5.
To confirm the settings, tap the
Checkmark
icon.
Specifying the minimum input setting to measure air flow
If you are using a DP transmitter, set the minimum pressure input. If you are using a flow sensor, set the minimum flow input.
1. On the home screen, tap the
Settings
icon to enter the
Settings
menu.
2. To view analog input settings, tap
Analog I/O
.
3.
To find the analog input you want to adjust, swipe left.
4. To change the minimum pressure input, tap the
Minimum Pressure Input
arrow.
5.
To confirm the settings, tap the
Checkmark
icon.
Setting up the duct area to measure air flow
If you are using a DP transmitter, specify the cross-sectional duct area in square inches. This duct area converts a differential pressure
or a velocity to a real-time volumetric flow, which can be used to calculate the air change rate. For round ducts, the cross-sectional area
can be determined by multiplying the square of the radius by pi. As an example, the cross-sectional area of a round 12 in. (304.8 mm)
duct, which has a radius of 6 in. (152.4 mm), is calculated as follows:
Area
round duct
= π * r
2
= 3.1416 * (6 in.)
2
= 113.09 in.
2
For rectangular ducts, the cross-sectional area can be determined by multiplying the length and width. As an example, the cross-
sectional area of a duct that measures 24 in. (609.6 mm) by 12 in. (304.8 mm) is calculated as follows:
Area
rectangular duct
= L * W = 24 in. * 12 in. = 288 in.
2
To specify the duct area for flow, complete the following steps:
1. On the home screen, tap the
Settings
icon to enter the
Settings
menu.
2. To view analog input settings, tap
Analog I/O
.
3.
To find the analog input you want to adjust, swipe left.
4. To specify the duct area, tap the
Duct Area
arrow and enter the result of your calculation.
5.
To confirm the settings, tap the
Checkmark
icon.