Hired-Hand Farm Hand Series: SCS w/Back-Up - Manual (Page 10)

Part No. 4801-5117 Rev. 8-01 Farm Hand SCS 8
To Back-
up Relay
hand the Fail-Safe relay strip would close each of the relays in the strip resulting in energizing the
ventilators in case of a controller power failure. Each of the relay strips contains four relays for
controlling four stages. In the SCS™ 16 there are a total of four relay strips, three will be N.O. and
one will be a Fail-Safe. In the SCS™ 8 there are two relay strips. One is a N.O. and one is a Fail-
Safe strip. The operator must insure that the Fail Safe relay strip is connected only to stages that
should be turned on in case of a controller failure. See Section 18 for a physical description of the
relay strips. It is not recommended to place heating equipment on Fail-Safe stages.
9. Curtain Operation During Back-up
The SCS contains a relay that can operate the curtains during Back-up operation of the SCS. The
curtains will automatically open during back-up based upon the selection of the back-up stage, either
COOL1, COOL2 or COOL 3. The SCS is shipped from the manufacturer with the Curtains connected
to the COOL 1 Stage. To change the Cool stage see Section 11.
10. Setting SCS™ Back-Up Stage Jumpers
Pictured at the right is a Stage Relay Board consisting of four stage relays and the associated stage
jumper for each stage relay. The stage jumpers a
labeled COOL 1, COOL 2, COOL 3 and HEAT.
Location of the jumper places the stage in one of
these four modes, or if the jumper is not inserted, the
stage is not placed on Back-Up. The jumpers
should be placed based on the operation of stage
equipment and should be the same as assigned in the
Master Controller. Jumpers are placed according the
following table:
Type of Stage
Operation
Jumper
Assignment
Cool Negative Fan COOL 1
Cool Negative
Tunnel Fan
COOL 2
Cool Tunnel Fan COOL 3
Heat Stage HEAT
Stage not on Back-
Up
No Jumper
Installed
11. Changing the SCS™ Curtain Back-Up Stage
At the top of the SCS relay board is a terminal strip labeled BACKUP
SYSTEM. Connect the jumper to the appropriate Stage, either COOL
1, COOL 2 or COOL 3. The SCS system is sent from the manufacturer
with the Backup curtain connection to COOL 1.
Stage
Jumpers
STAGE RELAY BOARD
Stage Relay
Stage
Harness
connector
cables to
Terminal
Block