Installation Manual

INS_FDX72_REV–
02/29/12
PAGE 5
FAULT CONDITIONS
TECH SUPPORT: 1.888.678.9427
INSTALLATION AND OPERATION MANUAL FDX72(M,S)1
A fault condition is when a FDX72 unit system loses power or optical link. The FDX72 provides three LED indicators to help identify
when and where fault conditions occur in a system:
1. ALARM relay output
2. STATUS LED
3. LINK A and LINK B LEDs
When a fault occurs, the ALARM relay on every FDX72 in the system goes from closed to open. In addition, the STATUS LED on
every FDX72 in the system goes from solid green to solid red. The LINK A and LINK B LEDs can then be used to identify the actual
location of the fault based on their color and pattern:
Solid Green Optical link has been established between this optical port and the adjacent FDX72 over fiber.
Furthermore, every other unit in the system is also reporting that link has been established. There are no faults in
the system.
Solid Red Optical link over this port has been lost.
This could be due to a broken fiber, a bad connection, or loss of power at the adjacent unit.
Blinking
Green/Red Optical link has been established between this optical port and the adjacent FDX72 over fiber.
However, a fault condition has been detected somewhere in the system. The LINK LED will be green for a
period of time, and then flash red some number of times. The number of red flashes indicates the location of
the fault by “hops” around the ring. If the LED flashes red three times, then the location of the fault is three hops
away (i.e. three FDX72 units away). For larger systems with faults greater than 9 hops away, the LED will use a
combination of long and short red flashes. Each long flash indicates 10 hops. Each short flash indicates 1 hop.
For example, a fault 47 hops away would be encoded as 4 long red flashes, followed immediately by 7 short
red flashes. The pattern repeats indefinitely until the fault is resolved.
Note Use of a FDX72 unit as an end point will always result in a fault condition. Use ComNet parts FDX70EA and
FDX70EB as end points in this system for accurate fault reporting.
FIGURE 9 – TYPICAL APPLICATION
Optical Fiber Optical Fiber Optical Fiber
FDX70EAS1
Unit 1
D
FDX72S1
Unit 3
D
FDX72S1
Unit 2
D
FDX70EBS1
Unit 4
D
DIN/DOUT DIN/DOUT
DIN/DOUT DIN/DOUT
A
B
A
B
A
B