Hired-Hand Farm Hand Series: SCS w/Back-Up - Manual (Page 8)

Part No. 4801-5117 Rev. 8-01 Farm Hand SCS 6
DIP Switch Settings SCS™
Stage
Address
Assignment
No. 1 No. 2 No. 3
ON ON ON 1 –16
OFF ON ON 17-32
ON OFF ON 33-48
OFF OFF ON 49-64
ON ON OFF 65-80
OFF ON OFF 81-96
ON OFF OFF 97-112
OFF OFF OFF 113-128
As discussed in Section 7, the SCS™ can be used with Back-Up. In the Local Network configuration
shown above, any one of the SCS™ units can be equipped with the Back-Up circuit board. Further,
only one Back-Up board is required within any Local Network. See Section 17.5 for a wiring
diagram.
7. Introduction to the SCS™ Back-Up System
The SCS™ system has the option of containing an
integrated Back-Up System. This Back-Up System
contains 4 stages: 1 Heat and 3 Cool. This system’s
purpose is to back up the master controller in the case
of failure. The Back-Up System is a stand-alone
control system. It contains its own temperature
sensors that react to a High and Low Limit. It
contains its own drive relays that are capable of
overriding the master controller and the stage switches
that are located on the SCS™ panel.
This Back-Up System is unlike any emergency control
system on the market. This system offers a much
higher level of protection. In addition to being able to
monitor for high and low temperatures, it also stays in constant communication with the master
controller. This communication allows the Back-Up System to run a minimum ventilation timer on
Cool 1 or override the SCS™ panel if certain conditions warrant. The conditions are explained in
Section 8. All Back-Up Systems can protect against a high or low temperature but only this system
can protect against today’s biggest grower concern: MINIMUM VENTILATION FAILURE.
8. SCS™ Back-Up Operating Conditions
As explained above, this is more than your customary Back-Up System. This system contains three
separate modes of operation that are entered depending on the circumstances. These modes are
Normal Operation, Emergency Operation, and Override Operation. These modes will be explained in
more detail below. These modes are entered based on information that it has received, or not
received, from the master controller. No matter what mode of operation the Back-Up System is in, it
will always attempt to maintain the temperature inside the High and Low Limits.
8.1 Normal SCS™ Operation
During Normal Operation, the Back-Up System always maintains the temperature between its high
and low limits. It accomplishes this by using its temperature sensors and its four stage outputs. If the
temperature drops below the Low Limit, the Heat stage will come on. That stage will not turn off until