FMS-2000C
LIT-12013504
37
Specifying the K-Factor to measure air flow
The default value for the K-Factor is 1.0, but the manufacturer of the sensor can provide a different K-Factor to serve as a correction
factor for the actual output of the sensor. If you do not receive a different K-Factor from the manufacturer, leave the K-Factor at its
default value. If you have to specify a different K-Factor, 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. On the
ANALOG
screen, tap K-Factor.
5. Enter the
K-Factor
that the manufacturer provided with the sensor.
6.
To confirm the settings, tap the
Checkmark
icon.
Calculating air changes per hour
If you want to measure air changes based on modes of occupancy or display air changes on the home screen, calculate air changes per
hour (ACPH). When you enable the calculation of ACPH, you have to enter the room volume and the ACPH setpoints for both occupied
mode and unoccupied mode.
To enter the ACPH setpoints for occupied and unoccupied modes, 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 set up
ANALOG 2
for flow, swipe left once.
4. To enable the calculation of ACPH, switch
Calculate ACPH
on.
5. Tap the
Occupied ACPH Setpoint
arrow and enter the setpoint value.
6. Tap the
Checkmark
icon to confirm your settings.
7. Tap the
Unoccupied ACPH Setpoint
arrow and enter the setpoint value.
8. Tap the
Checkmark
icon to confirm your settings.
Note:
The occupied and unoccupied specifications are only available in AI-2. When you set up AI-3 or AI-4 for flow, you can enter a
room volume value and an ACPH setpoint value only.
Calculating the room volume for ACPH measurement
To calculate the room volume of a rectangular room in cubic feet, multiply the length of the room by the width and the height. For
irregular shaped rooms, determine the value by breaking the room up into multiple smaller rectangular areas and summing the individual
volumes to calculate the total room volume in cubic feet. An approximation can also be specified for the room volume. This volume can
be fine-tuned to increase the accuracy of the displayed air change rate according to the actual volumetric flow offset of the room.
To enter the room volume, 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 enable the calculation of ACPH, switch
Calculate ACPH
on.
5. Scroll down and tap the
Room Volume
arrow.
6. Enter the room value you have calculated and tap the
Checkmark
icon to confirm your settings.
Specifying the output signal range for air flow
When you select the 0-5V, 0-10V, 0-20mA range, the analog output swings from zero to maximum specified by the hardware DIP switch
selection. The 1-5V, 2-10V, 4-20mA range includes an offset from zero. To specify the output range, 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 output range, expand
Range
.
5. To select a range, tap one of the following:
•
0-5V, 0-10V, 0-20mA
•
1-5V, 2-10V, 4-20mA
6. Collapse
Range
to save the new settings.
Adjusting deadband for air flow
This parameter specifies the deadband applied to the differential pressure input signal for control purposes. When the input signal is
within the deadband, the corresponding PID control output remains constant.
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. On the
ANALOG
screen, tap the
Deadband
arrow.
5. Enter the
Deadband
value.
6.
To confirm the new settings, tap the
Checkmark
icon.
