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Wiring Requirements for SLC Devices
5.4 Wiring Requirements for SLC Devices
The following information applies to SLC devices. Refer to the section that describes the type of device you are installing for details.
5.4.1 Wire Sizing for Internal SLC
The SLC requires use of a specific wire type, depending on mode of operation, to ensure proper circuit functioning. Wire size should be
no smaller than 18 AWG and no larger that 12 AWG wire. The wire size depends on the length of the SLC circuit. It is recommended that
all wiring be twisted-pair to minimize the effects of electrical interference
Wiring Requirements for Velociti Mode Modules
The GWF-7075 SLC can be programmed to operate in Velociti. Use Table 5.2 to determine the specific wiring requirements for the SLC.
Wire Requirements
RECOMMENDED: Twisted-unshielded pair, 12
to 8 AWG (3.31mm
maximum per length of Class A and Class X, 50
ohms per branch maximum for Class B loop.
Untwisted, unshielded wire, in conduit or
outside of conduit.
Twisted, shielded pair Note:
• Shields must be isolated from ground
• Shields should be broken at each device
Note: The maximum total capacitance of all SLC wiring (both between conductors and from any conductor to ground) should not exceed
0.5 micro farads.
Figure 5.1 and Figure 5.2 show how wire length is determined for out & back tap and T-Tap.
Note 1: The dotted line path
shows you how to calculate
the wire distance for the SLC
device at the end of the run.
The wire distance must be
less than the maximum per
wire gauge.
Note 2:
SK/DP device max. loop resistance = 40 ohms.
SD device max. loop resistance
When using T-taps, the total length of all taps and the main bus must be met in addition to the maximum distance requirements for the
various wire gauges.
SLC Wiring
In this example,
Use 18 AWG, because it is the
greatest distance 3,500 feet.
GWF-7075 Manual - P/N LS10147-002GF-E:E 06/11/2019
2
2
to 0.82 mm
). 50 ohms,
Table 5.2 SLC Wiring Requirements for Velociti modules
SLC Circuit
SLC Device
= 50 ohms.
Figure 5.1 Calculating wire run length for a simple out and back
= 1,000 feet
= 1,600 feet
= 3,500 feet
Figure 5.2 Calculating Wire Run Length for a T-tap
Distance in Feet (meters)
3,700 ft. (1,127.76 m)
9,500 ft. (2895.6 m)
6,000 ft. (1,828.8 m)
12,500 ft. (3,810 m)
3,700 ft. (,127.76 m)
5,000 ft. (1,528 m)
3,700 ft. (1,127.76 m) 5,000 ft. (1524 m)
SLC Device
SLC Device
Velociti® and SWIFT™ SLC Device Installation
Wire Type
2
12 AWG (3.31 mm
)
16 AWG (1.31 mm
2
14 AWG (2.08 mm
)
18 AWG (0.82 mm
2
12 to 16 AWG (3.31
mm to 1.31 mm
18 AWG (0.82 mm)
12 to 16 AWG (3.31 mm
2
18 AWG (0.82 mm
)
SLC Device
SLC Device
SLC Device
Note 1: The device located farthest from
the SLC must be less than the maximum
distance per wire gauge.
Note 2: SK/DP device max. loop
resistance = 40 ohms
SD device max. loop resistance = 50
ohms
Note 3: Additional Wiring Requirements:
If you use Isolator Devices:
Use up to 50 devices per branch.
Use up to 10Q of resistance per branc.
2
)
2
)
2
)
2
2
to 1.31 mm
)
35
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