The following table describes the attributes used by the Min OA Fan Variable Capacity Flow Control modules:
Name |
Type 1 |
Description |
Default Value |
---|---|---|---|
Damper Delay |
Allows the damper to start opening before the fan is energized. The damper delay defines the amount of time between the damper opening and the fan starting. |
30 Seconds |
|
Damper OpenClose |
Contains the control signal for the minimum OA damper. The enumeration set only has two values, Close and Open. |
Close Set Name: Close/Open |
|
Fan OnOff |
Binary signal for the minimum injection fan. The enumeration set only has two values, Off and On. |
Off Set Name: Off/On |
|
Fan Percent Cmd |
Analog signal for the minimum injection fan, it is used to command a fan speed. This output can range from 0% to 100%. |
0% |
|
Low Limit Delay |
Defines the time the damper remains closed once the low limit process variable rises above the low limit setpoint minus the deadband. |
180 Seconds |
|
Low Limit Process Variable |
Specifies the low limit temperature process variable. This temperature is usually the mixed air temperature or the preheat air temperature. |
7 °C, 45 °F |
|
Low Limit Proportional Band |
Defines the temperature range where the damper is proportionally modulated to control the mixed air temperature to the low limit temperature setpoint. |
5 °C, 9 °F |
|
Low Limit Setpoint |
Upper threshold for the low limit process function. When the low limit process variable is above this temperature, the minimum injection fan may be modulated to provide adequate levels of outdoor air. Below this setpoint, outdoor air levels may be limited by resetting the flow setpoint to control the low limit process variable to the low limit setpoint. |
7 °C, 45 °F |
|
Minimum OA Flow |
Flow through the minimum OA damper. |
940 l/s, 2000 cfm |
|
Minimum OA Flow Setpoint |
Contains the desired flow through the minimum OA damper. This module does not perform any setpoint reset. If that function is desired, it must be performed in another module. |
940 l/s, 2000 cfm |
|
MOAFLOW-RANGE (Minimum OA Flow Range) |
Specifies that the magnitude of the range that the PID Process Variable traverses as the PID Present Value varies between its minimum and maximum values. For example, when the Process Variable ranges between 200 and 2000 l/s due to the PID Present Value varying from is Low Limit to its High Limit, then Process Range is set to 1800 (|2000 - 200|). This input is location specific. |
850 l/s, 1800 cfm |
|
MOA-OUTSTATE (State) |
Represents the current module mode of operation. |
No Flow Set Name: AHU MinOA VFD Fan State |
|
Mode |
Desired mode of operation. |
No Flow Set Name: AHU MinOA VFD Fan Mode |
|
Output Overridden |
Indicates when the actual output controlled by this output is overridden by a user. |
False |
|
Output Position |
Provides the current Present Value of the output that this controller drives. |
0% |
|
PID Tuning Reset |
Causes the PID objects to reset their tuning parameters to the default based on the appropriate Process ID. |
Normal Set Name: PID Tuning Reset |
|
Process Units |
Specifies the units for the PID. For this particular module, l/s, cu m/h, and cfm are the only valid values. |
l/s, cfm Set Name: Unit |
|
Unrel Flow Mode |
Defines the module behavior when the flow station sensor is unreliable. |
No Flow Set Name: NoFlow/Flow |