3 Minute Read
| Overview
The DAB terminal profile is a profile that controls the terminal equipment of a space, which is provided by an RTU or an AHU for its HVAC needs. The profile is supported by a SmartNode, a Smart Damper, and a Smart Damper Actuator to provide the necessary control outputs based on the profile configured.
| How it Works
75F Dynamic Airflow Balancing operates to help temperature balance a system without fully closing off zones and creating harmful back pressure on the AHU.
Once you select the DAB terminal profile under SmartNode DAB profiles, the configuration provides the options to define the damper types, size, shape, and zone priority. It also provides the options to define the minimum and maximum damper positions during heating and cooling along with the Temperature Offset.
Additionally, the profile provides options to modify the controls based on the Internal Air Quality and Co2, with the IAQ and Co2 control that can be enabled or disabled.
Normally the Algorithm continuously tracks the current temperature of the zone and looks for the change in the difference between the terminal level Desired Temperature and Current Temperature and provides an optimal damper opening position within the deadband range, which is a resultant of the loop output based on the PI loop for control signals.
When the Current Temperature increases above the set point or desired temperature, the zone calls for cooling from the system or building-level equipment.
And when the Current Temperature decreases below the set point or desired temperature, the zones call for Heating from the system or building-level equipment.
The building or system-level device is an RTU or AHU which is controlled by the system-level DAB profiles.
For more information on the system-level DAB, profiles refer below.
DAB Staged RTU - Wiring/ Configuration
DAB Fully Modulating AHU - Wiring/ Configuration
DAB Advanced Hybrid AHU - Wiring/ Configuration
When the Co2 or the IAQ control is enabled, the algorithm takes the target and threshold values of Co2 and VOC into consideration. An increase in the value from the threshold value results in a loop output, and it changes the minimum damper position for the actual control to the changes in percentage value.
This resultant loop output is called the Co2 loop output, which is simply the weighted average Co2 loop output for all the zones that have Co2 control enabled.
Example- If the target and threshold are 1000ppm and 800, measured Co2 is 850 and configured damper limits are 0-100. The algorithm starts raising the minimum damper position proportionally from 800. A Co2 measurement of 850 will yield a loop output of 25%. This raises the damper's min position so that it now varies in the range of 25 – 100 based on temperature.
| Wiring
Below is a wiring schematic for the DAB terminal profile, that shows the connection between the SmartNode, Damper Actuator, and the Damper.
A Temperature and Humidity only sensor, which can be a Wall Sensor/Ceiling Sensor/Duct Sensor/Flush Mount Sensor is connected to the RTS port of the SmartNode.
Points to be considered while wiring
When installing a Belimo actuator, use the 18gauge thermostat wire for connections between SmartNode and Actuator.
For the sensors, both ends of the harness are the same male connectors. Plug one end into the Wall Sensor. Plug the other end into the RTS port on the SmartNode.
| Configuration Steps
To configure a DAB Terminal Profile.
- Click the pair module from the floor layout screen.
- Click the SN (SmartNode) from the select device type, screen.
- Click the DAB from the select module type, screen.
- Select the DAB Profile under DAB.
- Click Pair, to pair the device using the pairing instructions on the pairing steps screen.
- Select the device MAC address relayed for pairing, or click connect manually to pair the device manually. For more information on manual pairing refer to Alternate/ Manual Pairing for SmartNode.
- Enter the pin displayed on the SmartNode device or an automatic pairing.
- Click Pair.
Below is the configuration screen for the DAB terminal profile.
Once you've paired the SmartNode as a DAB profile, and once a few specific configuration parameters that define the physical characteristics of the setup are set in the configuration screen, the 75F sequence for the DAB will influence and control the setup.
| Configuration Parameters
Damper Type
Following are the damper types the 75F system supports
Damper 1 Type
Type of actuator being controlled on Damper port 1 or Analog out 1. 75F Smart Dampers is controlled using an MAT actuator through Damper port 1. If you are using a modulating 0-10Vdc type, then Damper 1 Type will be Analog Out 1 and will read TH1 for the DAT.
Damper 2 Type
Type of actuator being controlled on Damper port 2 or Analog out 2. 75F Smart Dampers are controlled using an MAT actuator through Damper port 2. If you are using a modulating 0-10Vdc type, then Damper 2 Type will be Analog Out 2 and will read TH2 for the DAT.
Use Reheat
It is a provision to include Reheat capability in the profile for more information on the reheat aspect refer to Reheat for DAB Terminal Profile
Size -Size of the associated damper. Used for calculating CFM.
Shape - Shape of the associated damper. Also used for calculating CFM.
Zone Priority -Used in calculations for driving the AHU into heating or cooling. (Low = 1, Normal = 10, High = 50)
Enable IAQ Control -Must have an IAQ sensor present. Nonstandard option.
Enable Co2 Control - Must have a Co2 sensor present. Nonstandard option.
Enable Occupancy Control - Must have an Occupancy Sensor present. Nonstandard option.
Enable CFM- To enable operation based on the Airflow in cubic feet per minute calculation. For more information refer to True CFM (Cubic Feet per Minute)
Temperature Offset -Value applied to the current temperature reading if the current temperature needs calibration. Sensors should not typically need calibration.
Min/ Max Damper Positions -Hard limits on damper positions in a given mode.
Once the required parameters are configured
- Click set to confirm the configuration.
| Post Configuration
Once a DAB terminal profile is configured the same is visualized in the CCU as below.
And in portals as below.
| Operation
Considering there is more than one terminal profile connected to the DAB system profile when the zones are within the deadband the damper positions are managed using the terminal level loop output.
When the temperatures cross the Deadband and zones call for cooling or heating from the system level equipment, the cooling or heating which the system level equipment provides is divided optimally for the zones, to help temperature balance a system without fully closing off zones and creating harmful back pressure on the AHU. This is achieved based on two approaches.
-
Normalization
- Minimum overall Damper Position
Which is based on the DAB profile sequences and uses the aspects like the Zone priority, Damper size, and other tuner parameters for the output calculations.
| Equip Graphics
Equipment graphics is available for all the terminal profiles. It provides a graphical representation of system-level equipment and enables monitoring of key point parameters associated with terminal profiles, along with the alert rings and alert severity legends displayed.
| Sequence of Operation
The sequence of operation is completely driven based on Occupancy mode, Space Current Temperature, the set Cooling and Heating Desired Temperatures, CFM, and Space CO2 & VOC levels.
Let us understand the Sequence of operations based on the occupancy modes, and how the other factors contribute to the sequence of operations during different types of occupancy modes.
| Occupancy Modes
The occupancy mode (Occupied or Unoccupied) shall be determined through a user-adjustable, graphical, seven-day schedule with a holiday schedule, alongside the configurable autoaway and forced occupied options (external schedule influencers) for optimized controls and enhanced energy savings.
Based on the above aspects factoring into the occupancy the following can be the possible applicable occupancy modes:
-
- Pre- Conditioning
- Occupied
- Unoccupied
- Auto-Away
- Forced Occupied
| Sequence of Operation During Pre-Conditioning
Pre-conditioning is a state just before the building enters the scheduled occupancy. It starts at more like the unoccupied state, the desired temperatures drift to unoccupied setbacks.
The preconditioning uses an algorithm to start the conditioning before the building schedule, from the heating side or cooling side, to bring the building to an optimum level ( within the occupied heating & cooling desired temperatures) exactly at the time of occupancy start.
The zones would operate as shown below to accommodate the preconditioning from the system equipment.
A coolingPreconditioningRate and heatingPreconditiningRate tuners defaulted to 15 minutes, are used alongside the occupied heating/cooling desired temperature breach to determine when the pre-conditioning should start.
Example Calculation:
When,
-
- The heating & cooling desired temperatures are 70F and 74F for the building,
- The current temperature is 76F (Average of zone temperatures),
- 8:00 AM is the time the building is scheduled to be occupied.
Then the preconditioning start time is calculated as follows:
Cooling Desired Temperature Breach= 76-74=2F
Preconditioning duration= coolingPreconditioningRate (mins) * Cooling Desired Temperature Breach
= 15*2
= 30 mins
The preconditioning starts 30 minutes before the building is scheduled to be occupied, which is = 7:30 AM
During Warm-up:
-
- If the space temperature is below the occupied heating desired temperature, the space utilizes the warm-up via HeatingLoopOutput as below.
| If System Equipment in Cooling Mode | If System Equipment in Heating Mode |
|
The Damper remains at a minimum |
The HeatingLoopOutput is mapped to the Damper position actuator For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
-
- The CO2 and IAQ loops are disabled. (If configured for)
- The CFM loop is disabled. (If configured for)
During Pre-cooling:
-
- If the space temperature is below the occupied cooling desired temperature, the space utilizes the morning pre-cooling via CoolingLoopOutput, as below.
| If System Equipment in Cooling Mode | If System Equipment in Heating Mode |
|
The CoolingLoopOutput is mapped to the Damper position actuator for the damper position between the min-max damper position cooling. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
The Damper position moves to the minimum position |
- The CO2 and IAQ loops are disabled. (If configured for)
| Sequence of Operation During Occupied
At all occupied times: (based on a set schedule)
- The device maintains a space temperature within the Heating Desired Temperature and Cooling Desired Temperature Range.
During Deadband:
During deadband, the damper operation is influenced, based on the configuration of the profile, as follows.
| Configuration | Damper Operation |
| If only the zone temperature-based configuration is enabled. |
The damper shall be at its minimum position and the reheat valve will remain closed. The Dmaper minimum is decided based on the last known conditioning,
|
| If zone Temperature & CO2-based configuration is enabled. |
The Damper position is driven based on the Zone CO2 levels. For more information on the actual calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation Note: It is possible and likely that temperature control will not be as good when IAQ controls override the damper position. This is indicated by the iaqOverridingDamper being set to true. |
| If zone Temperature & VOC-based configuration is enabled. |
The Damper position is driven based on the Zone VOC levels. For more information on the actual calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation Note: It is possible and likely that temperature control will not be as good when IAQ controls override the damper position. This is indicated by the iaqOverridingDamper being set to true. |
| If zone Temperature & CFM-based configuration is enabled. | The Damper position is driven based on the min-max CFM set. For more information on the actual calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
| If zone Temperature, IAQ(CO2 & VOC) & CFM-based configuration is enabled. | The Damper position is driven based on Temperaue, IAQ, and CFM. For more information on the actual calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
During Heating:
-
- When the space current temperature falls below the HeatingDesiredTemperature the HeatingLoopOutput is enabled as below as below.
| If System Equipment is in Cooling Mode | If System Equipment in Heating Mode |
|
The Damper remains at a minimum from 0% - 50% of the Heating Loop Output, till a maximum Discharge Air Temperature (DAT) is reached, defined by the reheatZoneMaxDischargeTemp tuner (90) Then the Reheat loop output is enabled, based on the DAT set point and actual DAT for the loop output calculation. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
The HeatingLoopOutput is mapped to the Damper position actuator and further to modulating reheat or reheat stages. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
-
- When the space CO2 & IAQ levels are above the thresholds the CO2/ IAQ loop Outputs drive the damper actuator for damper position. for more information refer to DAB Terminal Profile- Damper Position Calculation & Operation.
-
- The CFM loop is disabled. (If configured for)
During Cooling:
-
- When the space current temperature is above the Cooling Desired Temperature the CoolingLoopOutput is enabled, as below
| If System Equipment in Cooling Mode | If System Equipment in Heating Mode |
|
The CoolingLoopOutput is mapped to the Damper position actuator for the damper position between the min-max damper position cooling. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation The CFM loop is enabled (If configured for) which is mapped to the Damper position actuator for more information on the CFM influence on the operation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
The Damper position moves to the minimum position, not allowing further hot air into the room. The Active airflow setpoint will be no higher than the minimum endpoint (minimum Cfm) |
-
- When the space CO2 & IAQ levels are above the thresholds the CO2/ IAQ loop Outputs drive the damper actuator for the damper position. for more information refer to DAB Terminal Profile- Damper Position Calculation & Operation
Note: The fan runs wherever the zone is occupied and when the reheat is enabled.
| Sequence of Operation During Autoaway
-
- The range of Heating Desired Temperature and Cooling Desired Temperature drifts further away.
- The device maintains a space temperature within the newly set Heating Desired Temperature and Cooling Desired Temperature Range.
During Deadband:
-
- CoolingLoopOutput, HeatingLoopOutput, CFM LoopOutput, CO2 and IAQ Loop Output, and Reheat Stages are disabled.
During Heating:
-
- When the space current temperature falls below the heating autoaway setback temperature, the HeatingLoopOutput is enabled as below.
| If System Equipment in Cooling Mode | If System Equipment in Heating Mode |
|
The Damper remains at a minimum from 0% - 50% of the Heating Loop Output, till a maximum Discharge Air Temperature (DAT) is reached, defined by the reheatZoneMaxDischargeTemp tuner (90) Then the Reheat loop output is enabled, based on the DAT set point and actual DAT for the loop output calculation. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
The HeatingLoopOutput is mapped to the Damper position actuator and further to modulating reheat or reheat stages. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
-
- The CO2 and IAQ loops are disabled. (If configured for)
- The CFM loop is disabled. (If configured for)
During Cooling:
-
- When the space current is above the cooling the CoolingLoopOutput is enabled, as below.
| If System Equipment in Cooling Mode | If System Equipment in Heating Mode |
|
The CoolingLoopOutput is mapped to the Damper position actuator for the damper position between the min-max damper position cooling. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation The CFM loop is enabled (If configured for) which is mapped to the Damper position actuator for more information on the CFM influence on the operation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
The Damper position moves to the minimum position, not allowing further hot air into the room. The Active airflow setpoint will be no higher than the minimum endpoint (minimum Cfm) |
-
- The CO2 and IAQ loops are disabled. (If configured for)
Note: The fan runs wherever the zone is occupied and when the reheat is enabled.
| Sequence of Operation During Unoccupied
-
- The range of Heating Desired Temperature and Cooling Desired Temperature drifts further away.
- The device maintains a space temperature within the newly set Heating Desired Temperature and Cooling Desired Temperature Range.
During Deadband:
During deadband, the damper operation is influenced, based on the configuration of the profile, as follows.
| Configuration | Damper Operation |
| If only the zone temperature-based configuration is enabled. |
The damper shall be at its minimum position and the reheat valve will remain closed. The Dmaper minimum is decided based on the last known conditioning,
|
| If zone Temperature & CO2-based configuration is enabled. |
The Damper position is driven based on the Zone CO2 levels. For more information on the actual calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation Note: It is possible and likely that temperature control will not be as good when IAQ controls override the damper position. This is indicated by the iaqOverridingDamper being set to true. |
| If zone Temperature & VOC-based configuration is enabled. |
The Damper position is driven based on the Zone VOC levels. For more information on the actual calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation Note: It is possible and likely that temperature control will not be as good when IAQ controls override the damper position. This is indicated by the iaqOverridingDamper being set to true. |
| If zone Temperature & CFM-based configuration is enabled. | The Damper position is driven based on the min-max CFM set. For more information on the actual calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
| If zone Temperature, IAQ(CO2 & VOC) & CFM-based configuration is enabled. | The Damper position is driven based on Temperaue, IAQ, and CFM. For more information on the actual calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
During Heating:
-
- When the space's current temperature falls below the heating the HeatingLoopOutput is enabled as below.
| If System Equipment in Cooling Mode | If System Equipment in Heating Mode |
|
The Damper remains at a minimum from 0% - 50% of the Heating Loop Output, till a maximum Discharge Air Temperature (DAT) is reached, defined by the reheatZoneMaxDischargeTemp tuner (90) Then the Reheat loop output is enabled, based on the DAT set point and actual DAT for the loop output calculation. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
The HeatingLoopOutput is mapped to the Damper position actuator and further to modulating reheat or reheat stages. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
-
- The CO2 and IAQ loops are disabled. (If configured for)
- The CFM loop is disabled. (If configured for)
During Cooling:
-
- When the space current temperature is above the cooling the CoolingLoopOutput is enabled, as below.
| If System Equipment in Cooling Mode | If System Equipment in Heating Mode |
|
The CoolingLoopOutput is mapped to the Damper position actuator for the damper position between the min-max damper position cooling. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation The CFM loop is enabled (If configured for) which is mapped to the Damper position actuator for more information on the CFM influence on the operation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
The Damper position moves to the minimum position, not allowing further hot air into the room. The Active airflow setpoint will be no higher than the minimum endpoint (minimum Cfm) |
-
- The CO2 and IAQ loops are disabled. (If configured for)
Note: The fan runs wherever the zone is occupied and when the reheat is enabled.
| Sequence of Operation During Forced Occupied
-
- The device maintains a space temperature within the Heating Desired Temperature and Cooling Desired Temperature Range.
During Deadband:
During deadband, the damper operation is influenced, based on the configuration of the profile, as follows.
| Configuration | Damper Operation |
| If only the zone temperature-based configuration is enabled. |
The damper shall be at its minimum position and the reheat valve will remain closed. The Dmaper minimum is decided based on the last known conditioning,
|
| If zone Temperature & CO2-based configuration is enabled. |
The Damper position is driven based on the Zone CO2 levels. For more information on the actual calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation Note: It is possible and likely that temperature control will not be as good when IAQ controls override the damper position. This is indicated by the iaqOverridingDamper being set to true. |
| If zone Temperature & VOC-based configuration is enabled. |
The Damper position is driven based on the Zone VOC levels. For more information on the actual calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation Note: It is possible and likely that temperature control will not be as good when IAQ controls override the damper position. This is indicated by the iaqOverridingDamper being set to true. |
| If zone Temperature & CFM-based configuration is enabled. | The Damper position is driven based on the min-max CFM set. For more information on the actual calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
| If zone Temperature, IAQ(CO2 & VOC) & CFM-based configuration is enabled. | The Damper position is driven based on Temperaue, IAQ, and CFM. For more information on the actual calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
During Heating:
-
- When the space current temperature falls below the Heating Desired Temperature the HeatingLoopOutput is enabled as below.
| If System Equipment in Cooling Mode | If System Equipment in Heating Mode |
|
The Damper remains at a minimum from 0% - 50% of the Heating Loop Output, till a maximum Discharge Air Temperature (DAT) is reached, defined by the reheatZoneMaxDischargeTemp tuner (90) Then the Reheat loop output is enabled, based on the DAT set point and actual DAT for the loop output calculation. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
The HeatingLoopOutput is mapped to the Damper position actuator and further to modulating reheat or reheat stages. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
-
- The CO2 and IAQ loops are disabled. (If configured for)
- The CFM loop is disabled. (If configured for)
During Cooling:
-
- When the space current temperature is above the Cooling Desired Temperature the CoolingLoopOutput is enabled as below,
| If System Equipment in Cooling Mode | If System Equipment in Heating Mode |
|
The CoolingLoopOutput is mapped to the Damper position actuator for the damper position between the min-max damper position cooling. For more information on the Damper position calculation refer to DAB Terminal Profile- Damper Position Calculation & Operation The CFM loop is enabled (If configured for) which is mapped to the Damper position actuator for more information on the CFM influence on the operation refer to DAB Terminal Profile- Damper Position Calculation & Operation |
The Damper position moves to the minimum position, not allowing further hot air into the room. The Active airflow setpoint will be no higher than the minimum endpoint (minimum Cfm) |
- The CO2 and IAQ loops are disabled. (If configured for)
Note: The fan runs wherever the zone is occupied and when the reheat is enabled.
| Sequence of Operation During Emergency Conditioning
When zone limits are violated, and the recorded temperature is within the zone limit plus leeway the conditioning will happen in the direction of zone load.
| Sequence of Operation During Zone Temp Dead
And, When the zone temperature breaches the zone limits, beyond the leeway limits all the following loops are disabled:
-
- CoolingLoopOutput
- HeatingLoopOutput
- Reheat Stages
- FanLoopOutput
- CO2 & IAQ LoopOutput
- CFM LoopOutput
| Control Mode Summary
|
Modes & Operation |
Pre-Conditioning | Occupied | AutoAway | Unoccupied | Forced Occupied |
| Auto |
HeatingLoopOutput FanLoopOutput CoolingLoopOutput FanloopOutput CFMLoopOutput |
HeatingLoopOutput FanLoopOutput CoolingLoopOutput FanloopOutput CFMLoopOutput CO2LoopOutput IAQLoopOutput |
HeatingLoopOutput FanLoopOutput CoolingLoopOutput FanloopOutput |
HeatingLoopOutput FanLoopOutput CoolingLoopOutput FanloopOutput |
HeatingLoopOutput FanLoopOutput CoolingLoopOutput FanloopOutput |
| Heat Only |
HeatingLoopOutput FanLoopOutput |
HeatingLoopOutput FanLoopOutput CO2LoopOutput IAQLoopOutput |
HeatingLoopOutput FanLoopOutput |
HeatingLoopOutput FanLoopOutput |
HeatingLoopOutput FanLoopOutput CO2LoopOutput IAQLoopOutput |
| Cool Only |
CoolingLoopOutput FanLoopOutput CFMLoopOutout |
CoolingLoopOutput FanloopOutput CFMLoopOutput CO2LoopOutput IAQLoopOutput |
CoolingLoopOutput FanLoopOutput |
CoolingLoopOutput FanLoopOutput |
CoolingLoopOutput FanLoopOutput CO2LoopOutput IAQLoopOutput |
| Off |
All Loops Deactivated |
||||
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