User's Manual
13
Date Code 20170317 Instruction Manual SEL-FT50/SEL-FR12 Fault Transmitter and Receiver System
System Installation
performance. Use 4 mm
2
(12 AWG) or heavier wire of less than 2 meters
(6.6 feet) for this connection. Make the ground connection before making the
power connections.
Connect the power harness to a fused 12 V auxiliary power supply terminal on
the SEL-651R, paying attention to polarity.
If possible, turn on the SEL-FR12 and verify that the ENABLED LED
illuminates. Turn it off before continuing.
Connect the Serial Port
Use a short cable, such as the SEL-C272, to connect the serial output of the
SEL-FR12 to the recloser control or relay serial port that has been configured
for M
IRRORED BITS operation.
Turn on the SEL-FR12 and verify that the ROK LED illuminates. If ROK does
not assert, check the SEL-FR12 MIRRORED BITS Speed and Address switches
and compare them with the MIRRORED BITS port settings of the host device.
Turn it off before continuing.
Feed Lines
The feed line used with the antenna is important. Use coaxial cables that have
low attenuation and are rated for outdoor use. Keep the feed line as short as
possible to minimize signal loss between the radio and antenna. RG8X or
LMR-400 coaxial cables are preferred. If longer lengths or less cable loss
is
desired for the radio link, then you can use a larger cable, such as a 7/8-inch
HELIAX. Table 2 lists the signal losses for the indicated lengths of each cable type.
Antenna System Ground
Antenna system grounding is not included in the scope of this manual. Please
consult a radio systems engineer or other professional for advice on ground-
system design, and read AG2014-36, Radio System Lightning Protection Best
Practices, which can be found on the SEL website. A well-designed system
will minimize equipment damage and risk of electric shock to personnel.
Setting Network ID
To enable multiple wireless fault transmitter and fault receiver systems to
operate in close proximity, both the SEL-FT50 and SEL-FR12 feature a
Network ID selection (1–16). See Figure 11 for an example of two networks.
The SEL-FR12 will only receive transmissions from SEL-FT50 Fault
Transmitters that match its Network ID.
Each SEL-FT50 contain configuration switches to select one of sixteen
network identification numbers. The SEL-FR12 also has Network ID
Table 2 Length vs. Loss in Coaxial Cables at 900 MHz
Cable Type
Characteristic
Impedance
3.05 Meters
(10 Feet)
12.24 Meters
(50 Feet)
30.48 Meters
(100 Feet)
91.44 Meters
(300 Feet)
RG-8X
(SEL-C964, SEL-C975)
50 : 0.70 dB 3.50 dB 7.0 dB Unacceptable loss
LMR-400
(SEL-C966, SEL-C968)
50 : 0.39 dB 1.95 dB 3.90 dB Unacceptable loss
7/8-inch HELIAX
(SEL-C978)
50 : Do not use 0.64 dB 1.28 dB 3.84 dB