Hired-Hand Farm Hand Series: Stage Master - Manual (Page 17)

Part No. 4801-0151 Rev 4-06 Farm Hand Stage Master 17 of 40
Setting Stage Sensor Stage Mode Stage Timer OffPoint OnPoint
Cool Timer
Max % Cool Timer
Min %
Parameter P1 P2 P3 OFF ON P70 P71
Value 10 02 02 80 86 90 50
Option Sensor 1 Cool Stir Timer ON
Minimum
OnPoint Maximum
OnPoint Maximum
Runtime % Minimum
Runtime %
(ON=86). The stage will not run if the temperature is below the OffPoint, as shown in
Graph 1. When the temperature reaches the OffPoint, the stage is placed on the system timer.
To enhance temperature control, the Runtime percentage of a cool timer stage can be varied. The
percentage of the Runtime that the cool timer stage is ON can be varied when the temperature is
between the OffPoint and the OnPoint by setting parameters P70 and P71. In this example, the
Minimum Runtime percentage is 50%, as set by P71 = 50. The Maximum Runtime percentage is
90%, as set by P70 = 90.
When the temperature reaches 80ºF the stage runs for 50% of the Runtime period (2-1/2 minutes
if the system timer is set for 5 minutes, or 5 minutes if the system timer is set for 10 minutes). As
the temperature increases, the Runtime percentage of the stage progressively increases up to the
Maximum Runtime percentage of 90% when the temperature reaches 86ºF. Above 86ºF, the
Runtime percentage remains constant at 90%.
Table 1 Example Of Cool Timer Stage Operation
Brief Description Of Cool Timer Stage Operation
As you can see, a stage will be placed on the system timer once the temperature rises above 80ºF
(OFF) and will start running 50% (P71) of the time. If the temperature continues to increase then
the run time percentage will also increase toward 90% (P70).
9.5 Variable Speed Stage Operation
Depending on the Farm Hand Stage Master model, you have 0 or 2 variable stages. The Variable stages
can be used in one of two ways: Variable Speed or Progressive Cool Timer. The two options are selected
by the parameters P3. The following sections explain the operation of both options.
9.5.1 Variable Speed Stage Operation (Variable Stage Model Only)
Note: This option applies to stages 1 and 2 of the Variable Stage Farm Hand Stage Master.
The variable speed option (P3=0) allows the user to configure the variable stage to vary the speed of the
fan for their minimum ventilation needs. The following explains the setup and operation.
In this case, the stage timer setting is P3=0 to indicate variable speed operation. The Minimum OnPoint
(OFF) is set for 75ºF, and the Maximum OnPoint (ON) is set for 80ºF. This establishes the temperature
range (75º-80º) over which the speed is varied. The variable speed percentage is set by the "Var/Timer
75 80 85 90
Runtime Percentage
Graph 1 ON/Off Stages
86ºF
OnPoint
90
50
80º F
OffPoint
Temperature (F)