The calibration gain is used for the fine tuning adjustments which might need to be made to the airflow calculation. This number is calculated automatically by the zone controller after input to the air balance maintenance screen, or it can be input manually at this screen. For ease of use it is recommended to use the Air Balance Maintenance screen to determine this num- ber. The Air Balancing Maintenance screen will cause the val- ue to be updated during the balancing procedure.
If the Calibration Gain must be configured manually, it is determined as a percentage up or down that the CFM indicated will be offset. A number of .95 will cause the maximum air- flow calculated to be reduced to 95% of the value. A Calibra- tion Gain of 1.00 will cause no change. A number of 1.05 would cause readings to become 5% higher.
The Calibration Gain is adjusted on the Air Balance Mainte- nance screen when performing the Maximum Airflow calibra- tion and will have the greatest effect on the airflow at maxi- mum CFM. Any error in reading at minimum airflow is adjust- ed by calculating the Offset configuration value. After performing the air balance using the Air Balance Maintenance screen it is a good idea to upload and save the Calibration Gain and Offset values.
Calibration Gain: Range | 0.000 to 9.999 |
Default Value | 1.000 |
Offset — The Offset configuration is included for precision applications where the minimum airflow is critical and not ze- ro. This configuration indicates the amount of CFM the trans- ducer is off by, at minimum airflow, during the minimum air- flow test on the air balance screen. This configuration should not be used to zero the airflow transducer since an auto zero test is included on the air balance screen and is also automati- cally performed each time the equipment fan is disabled (or every 72 hours for systems which run the fan continuously). After performing the air balance testing using the Air Balance Maintenance screen it is a good idea to upload and save the Calibration gain and Offset values. The cfm will be offset by the value entered in the Minimum Cfm variable and will zero at the value entered in the Maximum Cfm variable. There will be a linear relationship between the two set points.
Offset: | Units | cfm |
| Range | |
| Default Value | 0 |
Damper Loop Parameters — The loop gains and start value define how the terminal will respond to deviations in measured CFM in order to control to the airflow set point.
The Proportional Gain is calculated each time the airflow is compared to the active airflow set point. As the error from set point goes to zero, the proportional term will also go to zero.
The Integral Gain is a running summation of all integral terms since the loop started. This has the effect of trimming off any offset from the set point which might occur, if only the pro- portional term existed. Normally a proportional loop with no integral term would require frequent adjustments of the starting value to eliminate the offset as static pressure and other condi- tions change.
The Derivative Gain is not needed. The Derivative Gain would tend to nullify large changes in the Proportional Gain for dampened response. These large changes in the Proportional Gain do not tend to happen for this type of control.
Damper Loop Parameters |
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Proportional Gain:Range | 00.0 to 99.9 | |
| Default Value | 30.0 |
Integral Gain: | Range | 00.0 to 99.0 |
| Default Value | 5.0 |
Derivative Gain: | Range | 00.0 |
| Default Value | 0.0 |
Start Value: | Units | % |
| Range | 0 to 100 |
| Default Value | 20 |
Clockwise Rotation — This configuration is used to define what effect a clockwise rotation of the actuator will have on the damper. If the actuator rotates clockwise to closed position, the configuration should be set to Close. If the actuator rotates clockwise to open, the configuration should be set to open. This configuration is used to change the rotation of the actuator so that the damper transducer calibration will work properly. The actuator does not have to be
Clockwise |
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Rotation: | Range | Close/Open |
| Default Value | Close |
Pressure Independent — This configuration defines if the ter- minal will function in the pressure independent or pressure de- pendent mode.
NOTE: Pressure dependent mode should only be used in an emergency, if the pressure sensor is not functioning.
Pressure |
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Independent: | Range | No/Yes |
| Default Value | Yes |
→Heat Type — This configuration is used to define the type of heat installed on the terminal. A 0 is equal to None. A 1 is equal to Modulating/VAV. A 2 is equal to Two Position. A 3 is equal to staged Electric. A 4 is equal to Modulating/CV.
Heat Type: | Range | 0 to 4 |
| Default Value | 0 |
VAV Central Heating — The VAV Central Heating configura- tion is used if the air source has the ability to provide heat and the terminal is required to modulate, using the heat minimum and heat maximum airflows, when the air source is in the heat mode. If this variable is set to No, the terminal will use its available local heat to heat the zone at all times.
VAV Central |
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Heating: | Range | No/Yes |
| Default Value | Yes |
Heating Loop Parameters — The heating loop gains and start value define how the terminal will respond to deviations in measured space temperature in order to control to the heat set point.
The Proportional Gain is calculated each time the space temperature is compared to the heat set point. As the error from set point goes to zero, the Proportional Gain will also go to zero.
The Integral Gain is a running summation of all integral terms since the loop started. This has the affect of trimming off any offset from set point which might occur if only the Propor- tional Gain existed. Normally a proportional loop with no Inte- gral Gain would require frequent adjustments of the starting value to eliminate the offset as loading conditions on the room change.
The Derivative Gain is not needed. This term tends to nulli- fy large changes in the Proportional Gain for dampened response.
Heating Loop Parameters |
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Proportional Gain: Range | 00.0 to 99.9 | |
| Default Value | 8.0 |
Integral Gain: | Range | 00.0 to 99.0 |
| Default Value | 3.0 |
Derivative Gain: | Range | 00.0 |
| Default Value | 0.0 |
801 | 40 |
