Controlling Airflow with an AFMS

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After Setting Up an AFMS, you can control outside air flow, or control mixed air temperature. Also, for setup or maintenance purposes, you can command a damper position.

Alternatively, you can pass through control of the damper actuator to an external controller, using the AFMS for measurement and monitoring only. (See Monitoring with an AFMS.)

Controlling Outside Air Flow

1. Go to AFMS , then select the Device Name of the AFMS controller.

2. Select the Configure tab.

3. From the Control Mode dropdown menu, select OA FLOW CTRL.

4. Enter an Outside Air Flow Setpoint (as CFM).

5. Select Save.

   Note: The outside air damper will modulate to maintain the Outside Air Flow Setpoint. If Enable Low Limit is ON and the mixed air temperature reaches the Low Temp Limit, the damper will modulate toward closed to prevent freezing of the equipment. If an occupancy sensor is used, this Control Mode will only be active when the served space is occupied.

Controlling Mixed Air Temperature

1. Go to AFMS , then select the Device Name of the AFMS controller.

2. From the tabs that appear, select Configure.

3. From the Control Mode dropdown menu, select MAT CTRL.

4. Enter a Mixed Air Temp Setpoint.

5. Select Save.

   Note: The outside air damper will modulate to maintain the Mixed Air Temp Setpoint. If Enable Low Limit is ON and the mixed air temperature reaches the Low Temp Limit, the damper will modulate toward closed to prevent freezing of the equipment. If an occupancy sensor is used, this Control Mode will only be active when the served space is occupied.

Commanding a Damper Position

1. Go to AFMS , then select the Device Name of the AFMS controller.

2. From the tabs that appear, select Configure.

3. From the Control Mode drop-down menu, select DMPR POSITION CTRL.

4. Enter an Outside Air Damper Setpoint (0–100% open).

5. Select Save.

   Note: The AFMS controller will command the damper to the Outside Air Damper Setpoint. If Enable Low Limit is ON and the mixed air temperature reaches the Low Temp Limit, the damper will modulate toward closed to prevent freezing of the equipment. If an occupancy sensor is used, this Control Mode will only be active when the served space is occupied.

Enabling Pass Through

1. Go to AFMS , then select the Device Name of the AFMS controller.

2. From the tabs that appear, select Configure.

3. From the Control Mode drop-down menu, select PASS THROUGH.

4. Select Save.

   Note: The external controller (if the AFMS controller is wired to one) will be allowed to control the damper actuator. (For wiring details, see the Airflow Measurement System Installation Guide, found on any AFMS controller's product page.) This Control Mode will only be active when Learn Damper Span and Learning Mode (under the Learn tab) are OFF.

   Warning: The Enable Low Limit and Low Temp Limit do not apply when in PASS THROUGH. Ensure the external controller has its own low limit and other safeties configured to prevent equipment damage.