The following table describes the attributes used by the Fan Return or Exhaust Volume Match Control modules.
|
Name |
Type 1 |
Description |
Default Value |
|---|---|---|---|
|
Fan Return or Exhaust Volume Match Common Attributes |
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|
EF-OUTSTATE or RF-OUTSTATE (State) |
V, G |
Indicates the current operational mode of the output controller. This output is the current state of the activity. |
Off Set Name: AHU RF VOL State |
|
Mode |
Contains the desired mode of operation. |
Off Set Name: AHU RF VOL Mode |
|
|
Process Units |
Allows the user to define the units for the process. |
l/s, cfm Set Name: Unit |
|
|
Return Fan Control Status |
V |
Displays the PID Status. The possible values are normal, overridden, disabled, low, timing low, high, and timing high. |
Normal Set Name: Control Status |
|
Return Fan OnOff |
V |
On/off signal for the return fan. |
Off Set Name: Off/On |
|
Return Fan Percent Cmd |
V |
Contains the analog signal for the return fan used to command a fan speed. This output can range from 0% to 100%. |
0.0% |
|
Return Flow |
Use to connect the return airflow or the exhaust airflow to this input. |
10000 l/s, 22000 cfm |
|
|
Supply Fan Percent Cmd |
Contains the analog signal from the supply fan used in the Failsoft mode. |
0.0% |
|
|
Supply Flow |
Discharge airflow. |
10000 l/s, 22000 cfm |
|
|
Vol Process 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, the process range should be configured to be the design flow of the return fan. |
10000 l/s, 22000 cfm |
|
|
Volume Diff Setpoint |
Contains the volume differential (Supply Flow - Return Flow or Supply Flow - Exhaust Flow) setpoint. |
0 l/s, 0 cfm |
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|
Variable Capacity Return Fan Volume Match Control Specific Attributes |
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Low Limit Process Variable |
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 flow differential setpoint is reset to control the low limit process variable to the low limit temperature setpoint. |
5 °C, 9 °F |
|
|
Low Limit Setpoint |
Contains the upper threshold for the low limit process function. When the low limit process variable is above this temperature, the return fan may be modulated to maintain the desired flow differential between the supply duct and the return duct. Below this setpoint, outdoor air levels may be limited by resetting the differential flow setpoint. |
7 °C, 45 °F |
|