Attributes (Min OA Fan Variable Capacity Flow Control) - Johnson Controls - Metasys - LIT-12011147 - Software Application - Controller Configuration Tool - 15.0

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Johnson Controls
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Controller Configuration Tool
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The following table describes the attributes used by the Min OA Fan Variable Capacity Flow Control modules:

Table 1. Min OA Fan Variable Capacity Flow Control Attributes


Type 1


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.


Set Name: Close/Open

Fan OnOff


Binary signal for the minimum injection fan. The enumeration set only has two values, Off and On.


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%.


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



Represents the current module mode of operation.

No Flow

Set Name: AHU MinOA VFD Fan State



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.


Output Position


Provides the current Present Value of the output that this controller drives.


PID Tuning Reset


Causes the PID objects to reset their tuning parameters to the default based on the appropriate Process ID.


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

1 C - Configuration Mode Only, G - Default Element (Generated State, if applicable), SC - Simulation and Commissioning Modes Only, V - Calculated Value (Outputs)