Hired-Hand Farm Hand Series: 4 Stage Controller - Manual (Page 8)

4801-5058 Rev 8-04 Farm Hand 4 Stage Controller 8 of 30
P20 -- Cycle Time
The controller looks at all parameters and decides whether or not to move
the curtains occasionally. This parameter determines how often this
occurs. Valid settings are 1 to 10 minutes.
P21 -- Run Time
When the controller determines that curtains need to run open or close,
this setting determines how long they run. Valid settings are 1 to 240
seconds.
P22 -- Initial Run Time
When the controller determines that the curtains should run open and
senses that they are closed, it uses this parameter for the ‘first’ run. This
setting is used to allow the curtains to open enough on the first run to
guarantee adequate ventilation. Valid settings are 1 to 240 seconds.
P23 -- Degrees above target for Unit 1
Generally a grower would like to give his variable speed and/or first stage
fans an opportunity to ventilate the building before starting curtains open.
Thus, when the curtains do come down, they will most likely stay down
for a fair period of time. This setting allows the user to do that. Valid
settings are: 0 - 25.
P24 – Degrees above target for Unit 2
Occasionally, a grower may want one curtain sidewall to drop before the
other to try to avoid large temperature swings. This setting allows for this
to happen. Note: If you would like both curtain units to always react
together, you must set P23 = P24.
P25 – Tunnel Onpoint
This is the sensor 3 temperature at which the controller will enter tunnel
mode. Only applicable when tunneling on outside temperature.
P26 -- Tunnel Offpoint
This is the sensor 3 temperature at which the controller will exit tunnel
mode. Only applicable when tunneling on outside temperature.
P27 -- Close Override (Degrees Below Target)
This setting provides the grower a temperature at which to override the
curtains closed. The setting represents degrees below target at which time
the curtains will begin closing regardless of the cycle. The setting allows
the user to anticipate quick temperature drops to help maintain a stable
inside temperature. Valid settings are 1-25.
6.3 Cool Timer Settings
The following two settings allow the user to set the Runtime range for their cool timer
stages.
P70 = Cool Timer Maximum Percentage
This sets the maximum Runtime percentage that a cool timer stage can operate.
P71 = Cool Timer Minimum Percentage
This sets the minimum Runtime percentage that a cool timer stage can operate.