The following table describes the attributes used by the Cooling Tower Control modules.
|
Name |
Description |
Default Value |
|---|---|---|
|
Blocking Protect |
This input causes the fan to run when the input value is Protect, Tower Enable is True, and System Enable is True. When this input is Protect and the system and tower are enabled, the fan runs for 5 seconds (default) once a week (default) |
Off Set Name: Blocking Protect |
|
Device OnOff |
Indicates the desired fan operation. This output is typically connected to either a constant speed fan or a variable speed fan. This output is also used for runtime totalization for this tower. |
Off Set Name: Off/On |
|
Fan Type |
This input indicates the tower configuration. The tower may be VFD, one speed fan, two speed fans, three speed fans, or vernier fan (a single fan with one or more one speed fans). |
VFD Set Name: Tower Fan Type |
|
Instant Shutdown |
This input provides a means to shut the tower down quickly. When true, the output’s Device OnOff, Speed 1 OnOff, Speed 2 OnOff and Speed 3 OnOff are set to Off. The Iso Valve Open Close output is set to Close. |
False |
|
Interstage Delay |
This input is the minimum time between switching speeds. |
120 Seconds Display Precision: 1s |
|
Iso Valve Cmd |
This input is the cooling tower isolation valve command. |
False |
|
Iso Valve OpenClose |
This output drives the isolation valve BO. |
Close Set Name: Close/Open |
|
Iso Valve Setup |
This input provides the cooling tower isolation valve setup. When set to Auto, the Iso Valve OpenClose output reflects the Iso Valve Cmd. When Set to On, the Iso Valve OpenClose output is always Open. |
Auto Set Name: Fan Mode Seq 4 |
|
Percent Cmd |
This indicates the desired speed of a variable speed fan. |
% |
|
Pid Pct Cmd |
This is the input from the Cooling Tower PID Control module. This input is the signal passed through for variable speed fans. |
0.0% |
|
Speed 1 Cmd |
Input from the sequencer indicating that the tower should operate in speed 1. |
False |
|
Speed 2 Cmd |
Input from the sequencer indicating that the tower should operate in speed 2. |
False |
|
Speed 3 Cmd |
Input from the sequencer indicating that the tower should operate in speed 3. |
False |
|
Speed 1 OnOff |
This is the desired fan speed 1 operation. This output is typically connected to a multi-speed fan’s low speed or speed 1 contactor. |
Off Set Name: Off/On |
|
Speed 2 OnOff |
This is the desired fan speed 2 operation. This output is typically connected to a multi-speed fan’s low speed or speed 2 contactor. |
Off Set Name: Off/On |
|
Speed 3 OnOff |
This is the desired fan speed 3 operation. This output is typically connected to a multi-speed fan’s low speed or speed 3 contactor. |
Off Set Name: Off/On |
|
State |
The current state of this output controller. |
Off Set Name: Fan Speed |
|
System Enable |
This input indicates when the chilled water system is enabled. |
True |
|
Tower Enable |
This input indicates when this tower is enabled. When the tower is enabled, any isolation valve associated with this tower is open. |
True |