Scully ST-15C Series, Technical Manual

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2.2.1 Power Connections
Route the mains power wires through the top left-hand entry hole in the top of enclosure. Connect mains
power wires to appropriate terminals on terminal block (strip) on the metal bracket in the enclosure. The
Power terminals are marked
E, N, & L , also shown in wiring diagram.
NOTE: The ST-15C Control Module is protected by a 1A high interrupt capacity fuse in the enclosure. The fuse (F1) is
located next to the terminal strip on metal bracket.
2.2.2 Enclosure Earth (Ground) Connection
Connect a wire (1.5mm
2
minimum) from the enclosure-bonding stud to earthed metallic structure of the
gantry (rack).
2.2.3 Control Output (Controlled Circuit) Connections
Route the control output wiring through the top right hand entry hole in the enclosure and connect to output
contact terminals, indicated on the terminal strip on metal bracket. The output control contact is open when
no connection from the controller is made to a vehicle (idle state). The output control contact closes when
sensor connected to the control unit is dry and functional (or when optional bypass switch is in the “Bypass”
position).
The contact opens if sensor gets wet (i.e. detects liquid). The contact also opens in case of a fault in the
sensor, wiring to the sensor or a fault within the control units’ circuitry.
NOTE:
An internal 5A high interrupt capacity fuse protects the output relay contact. The fuse (F2) is located on
metal bracket.
The output contact is rated 250VAC, 5A resistive maximum. It is used to close a valve or pump directly or
by wiring it in series with other control contacts, such as a preset meter’s control contacts. (See Diagram
61441, Typical Loading Rack Control in Appendix 4.0.) In addition it may also be connected to an input of a
terminal automation system (TAS) to provide status of the controller’s output to TAS.
Caution: A valve or pump should be directly controlled by ST-15C’s relay output contact. It should not go
via the logic circuits of a TAS, as that can introduce unsafe failure modes into this emergency shutdown
system. TAS may also control a valve or pump based on other conditions.
2.2.4 Intrinsically Safe Connections to Sculcon Plug & Cable Unit
Signals from ST-15C to Sculcon Plug & Cable Unit are intrinsically safe. The intrinsically safe connections
must only be made via the entry hole in the bottom of the enclosure. The connections are made to the
terminal strip TB2 at the bottom end of the printed circuit board module. The wires must be 1.5mm
2
(18AWG) minimum conductor size. Connect wires to Sculcon as shown in the Wiring Diagram in Appendix
4.0. Use wire colors as indicated. If other than suggested color codes are used, this information should be
so noted in the back of this manual for future reference and troubleshooting.
There is a factory installed jumper on TB2 terminals 1 and 2. Remove the jumper if the control unit is to be
used with Scully’s SP-BLHK heated product sensor. Otherwise, the jumper must be kept in place.
All wiring installation should be in accordance with local wiring codes.